Author Topic: Harold Hall's precision grinding table  (Read 54134 times)

Offline xo18thfa

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Harold Hall's precision grinding table
« on: March 03, 2011, 09:37:28 PM »
Something I’ve always wanted was a better way to grind HHS tooling for the lathe.  Research on the internet found a really neat precision grinding table designed and built by Harold Hall.   This is Mr Hall’s grinding table:



The table is used in conjunction with a regular bench grinder.  The plan for this table is in the “Workshop Practice Series #35, Milling, A Complete Course”



I started one of these and it’s about 1/3 done.





There are a series of attachments for the table.  They include a lathe tool grinding, drill bit sharpening, end mill sharpening and others.  My main purpose is for lathe tool, but would like to sharpen drill bits too.

It’s turning out very well so far.  I think it’s going to do the trick.
Bob Sorenson
Harrisburg, South Dakota, USA

Offline wheeltapper

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Re: Harold Hall's precision grinding table
« Reply #1 on: March 04, 2011, 05:48:04 AM »
Hi
looking good so far.
I made the simpler version and that works well.


Roy
I used to be confused, now I just don't know.

Offline Corvus corax

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Re: Harold Hall's precision grinding table
« Reply #2 on: March 04, 2011, 10:58:19 AM »
Both of the above rests are also detailed in Hall's other book:
Tool and Cutter Sharpening

Offline wheeltapper

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Re: Harold Hall's precision grinding table
« Reply #3 on: March 04, 2011, 11:38:55 AM »
I don't know what the OP plans but I've oil blacked mine since the pic.
Roy
I used to be confused, now I just don't know.

Offline xo18thfa

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Re: Harold Hall's precision grinding table
« Reply #4 on: March 04, 2011, 12:16:50 PM »
Roy, I remember your grinding table from a few months ago.  Yours got me started.

I am painting the non-machined surfaces on mine to prevent rust.  Fortunately there is almost no rusting problems here in Southern Nevada, but it will get a "spritz" of spray oil from time to time.

The clamping ability is good.  The plan calls for M8 threads, I used 5/16 x 18.  NF might be better.  After it's all done the clamping handles will need "tweeking" so they don't interfere.

I had to order another dovetail cutter.  Mine is to shallow.  In the mean time owrk on the rest of the parts.
« Last Edit: March 04, 2011, 12:22:18 PM by xo18thfa »
Bob Sorenson
Harrisburg, South Dakota, USA

Offline wheeltapper

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Re: Harold Hall's precision grinding table
« Reply #5 on: March 04, 2011, 01:38:48 PM »
Oh yea. I remember you now. :doh:
I've got a lousy memory for names.

I mentioned I'd oil blacked mine but I don't think I'll do anything else like that, the stink, and the mess.
Oh, did I mention the stink :(

plus it's wearing off, I must have got it too hot,...................or not hot enough..............or something.

Roy
I used to be confused, now I just don't know.

Offline madjackghengis

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Re: Harold Hall's precision grinding table
« Reply #6 on: March 11, 2011, 09:13:49 PM »
Both those tables look very useful and well made, as for the finish, I like to throw those kinds of things in my wood stove till they're red and then dump them in waste motor oil.  It does put up a stink and some smoke, but it gives a solid durable finish that holds oil, and won't rust easily.  I like it a lot.  very nice indeed. Jack

Offline xo18thfa

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Re: Harold Hall's precision grinding table
« Reply #7 on: March 12, 2011, 07:35:15 PM »
That's an interesting idea to use motor oil as a finish.  I'll try that.

Making progress on the Harold Hall grinding table.  I did a boneheaded thing and ordered the wrong size dovetail cutter for the slides.  So while waiting for the correct cutter, I got on some other parts.



Basically have the lathe tool grinding accessories done.  I am panning to do the drill bit sharpening attachment at some point too.

The adjustment knobs turned out very nice.



The increments were made on the lathe with a “V” held side ways in the tool post.  A piece of paper tape with 30 increments wrapped around the lathe chuck.  Each increment got three cuts, adding 0.002” depth for each cut.  At the end, a very light skim took off the burrs.

The lead screws have 32 threads per inch.  Each increment on the adjustment knob is 0.00104” (doing the math).
Bob Sorenson
Harrisburg, South Dakota, USA

Offline Bernd

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Re: Harold Hall's precision grinding table
« Reply #8 on: March 13, 2011, 12:54:52 PM »
Looking good Bob.

Real nice job on the dials. :thumbup:

Bernd
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Offline xo18thfa

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Re: Harold Hall's precision grinding table
« Reply #9 on: March 31, 2011, 10:08:04 PM »
Thanks Bernd

Got all the parts made for the Hall Grinding Table.  The sliding table portion is assembled and works great.  It was the first time I ever milled dovetails. 





I tried to assemble everything and immediately realized those fancy handles are not going to work.  They bump into everything and require too much fiddle to make work.  I am going to replace them with regular hex bolts and nuts.
Bob Sorenson
Harrisburg, South Dakota, USA

Offline sbwhart

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Re: Harold Hall's precision grinding table
« Reply #10 on: April 01, 2011, 01:44:11 AM »
Nice neat bit of maching there Bob  :thumbup:

Stew
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Re: Harold Hall's precision grinding table
« Reply #11 on: April 01, 2011, 02:47:29 AM »
Very nice Bob  :clap: :clap: :clap:  :dremel:


Rob

Offline Bernd

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Re: Harold Hall's precision grinding table
« Reply #12 on: April 01, 2011, 09:14:18 AM »
Lookin' good Bob.  :thumbup:

Bernd
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Offline xo18thfa

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Re: Harold Hall's precision grinding table
« Reply #13 on: April 03, 2011, 08:37:47 PM »
Thanks fellas.  The table itself is all done and ready to install.  My beautiful wife has given a "green light" to a new grinder.   :D :D



The grinder and table will either get mounted on a steel plate, or a piece of granite counter top I found on a junk pile.  Decided to take the handles off and use hex nuts.  The last part in Mr Hall's plan is a "cheater bar" to tighten the handles.  May as well just use a wrench.
Bob Sorenson
Harrisburg, South Dakota, USA

Offline xo18thfa

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Re: Harold Hall's precision grinding table
« Reply #14 on: May 09, 2011, 10:43:41 PM »
Finally got the Harold Hall grinding table installed and running.  It's nice, I like it.  The wheel is all trued up with a diamond point dresser.  It runs smooth as a baby's butt.  Got all new HSS lathe tools and we are cutting serious steel now.





Also made the drill bit grinding attachment.  It works very nice.  It cuts a razor sharp 4 facet edge.  I have a bloody finger to prove it.



I am glad I did this project.  It's a great addition to the shop.

Next up, a Harold Hall dividing head.
Bob Sorenson
Harrisburg, South Dakota, USA

Offline Bernd

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Re: Harold Hall's precision grinding table
« Reply #15 on: May 10, 2011, 09:08:42 AM »
Bob,

Very nice job.

That 4 facet drill sharpener is on my list of tooling needed.

Bernd
Route of the Black Diamonds

Offline wheeltapper

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Re: Harold Hall's precision grinding table
« Reply #16 on: May 10, 2011, 12:38:30 PM »
HI
looks good, I must make the drill sharpener thingie for mine.

Harolds dividing head is really good too, I've got one, I'll post some pics if I can find the camera.

Roy,
I used to be confused, now I just don't know.

Offline xo18thfa

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Re: Harold Hall's precision grinding table
« Reply #17 on: May 10, 2011, 12:39:26 PM »
Thanks Bernd, Roy.  The drill bit attachment works very well.  It was cumbersome to set up at first, but with a little practice, it goes quickly.

It was encouraging enough that I want to do the endmill attachment too, eventually.  It should do a good job on 2 flute mills.

Need to do a guard on the wheel.  The guard that came with the grinder interfered too much with the table.  So either modify it or make a new one.

Bob
Bob Sorenson
Harrisburg, South Dakota, USA

Offline wheeltapper

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Re: Harold Hall's precision grinding table
« Reply #18 on: May 10, 2011, 02:33:09 PM »
Hi
heres my attempt at Mr Halls dividing head.



simple dividing


compound



If you get his book' dividing' there is a chart in there that tells you all the divisions possible with three gears.

Roy



thanks to Photobucket for pics.

I used to be confused, now I just don't know.

Offline xo18thfa

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Re: Harold Hall's precision grinding table
« Reply #19 on: May 10, 2011, 05:51:34 PM »
Roy:  That's the one I want to do.  A friend of mine has a #2 Morse Taper ream.  Try that on the spindle.  Yours turned out great.  The pictures answer a lot of questions.

Thanks, Bob
Bob Sorenson
Harrisburg, South Dakota, USA

Offline Ashlyn Katarzyna

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Re: Harold Hall's precision grinding table
« Reply #20 on: May 19, 2011, 04:24:02 PM »
Thats pretty elaborate, I could only dream of doing something like that.  Keep us dated on the other goodies you make for it, good things take time!

Offline wheeltapper

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Re: Harold Hall's precision grinding table
« Reply #21 on: May 19, 2011, 05:29:59 PM »
Hi
It might look complicated but its only one bit at a time.
look at it that way and it gets easier.

Roy
I used to be confused, now I just don't know.

Offline Bernd

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Re: Harold Hall's precision grinding table
« Reply #22 on: May 24, 2011, 10:04:17 AM »
Bob,

Question. I noticed the dimensions are metric in the book. What did you do? Covert to the nearest imperial size or did you just convert the metric to inch and use that? Screws should be an easy conversion. I've got a chart to follow that. Thanks in advance.

Bernd
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Offline xo18thfa

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Re: Harold Hall's precision grinding table
« Reply #23 on: May 26, 2011, 10:50:47 PM »
Bob,

Question. I noticed the dimensions are metric in the book. What did you do? Covert to the nearest imperial size or did you just convert the metric to inch and use that? Screws should be an easy conversion. I've got a chart to follow that. Thanks in advance.

Bernd

Hi Bernd:  Converted to nearest inch size.  Don't recall running into any complications.

Bob
Bob Sorenson
Harrisburg, South Dakota, USA

Offline xo18thfa

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Re: Harold Hall's precision grinding table
« Reply #24 on: May 26, 2011, 10:51:21 PM »
The grinding table project is done.  Changed out the regular grinding wheel with a cone type wheel.  Put the wheel guard back on and modified it to fit the cone wheel.  Drilled and tapped more holes for the base bracket since the cone is much smaller then the regular wheel.

Here's the set up.



The drill bit attachment works great.  Did this 9/32" bit in about 10 minutes



This is a must have in the metal shop.  There is no excuse for dull lathe tools and drill bits now.  The next attachment will be the endmill sharpener.  I think this table is well capable of sharpening endmills.  Also want to make an attachment to hollow grind wood chisels.
Bob Sorenson
Harrisburg, South Dakota, USA

Offline Bernd

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Re: Harold Hall's precision grinding table
« Reply #25 on: May 27, 2011, 08:30:54 AM »

Hi Bernd:  Converted to nearest inch size.  Don't recall running into any complications.

Bob

I figured as much but wanted to make sure. I've studied the book quite intently and thought the same as far as the dimensions.

I'm going to see if I can fit the first two projects into my project list, the boring tool and indexer.

Again thanks for inspiration.

That grinding table looks great.  :bow:  :bow:  :thumbup:

Bernd
Route of the Black Diamonds

Offline wongster

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Re: Harold Hall's precision grinding table
« Reply #26 on: May 30, 2011, 10:38:22 AM »
Hi Bob,

I'm planning to make the simple version of the grinding table shown on the book on grinding and sharpening.  You think it will work the same if I choose to use aluminium instead of steel?

Regards,
Wong


Offline Anzaniste

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Re: Harold Hall's precision grinding table
« Reply #27 on: May 30, 2011, 07:49:31 PM »
Wong,
I am in the middle of making one. Aluminium would work but not very well it would wear out soon. The dovetail slides would not be very good in aluminum as aluminum/aluminum is not a good bearing combination.
Scrooby, 1 mile south of Gods own County.

Offline wongster

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Re: Harold Hall's precision grinding table
« Reply #28 on: May 30, 2011, 08:02:20 PM »
Thanks for your reply, Anzaniste.

If I use brass for the dovetails, would it work? 

There is a capscrew at the end of the fence (not the one locking the fence down from upright position).  Do you know its function?  Doesn't seem to be holding or pressing against anything.

Regards,
Wong

Offline xo18thfa

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Re: Harold Hall's precision grinding table
« Reply #29 on: June 01, 2011, 12:29:11 PM »
Hi Wong.  Go with steel for the table top.  The attachments sliding around will wear out aluminum quickly, and make a lot of friction as it scratches up.  There is no tricky machine work on the table top.  I think brass dovetails will work.  Brass is easier to machine.  My mill/drill chattered some when cutting them in steel.  The angle bracket at the bottom could be steel too, or extra heavy thick aluminum.  That part needs to be very rigid.  Aluminum for the rest should work out.  Mr Hall's plans are metric, if you are using inch, round up all the material thicknesses to make the table a bit more "beefy"  A little extra stout will help.

I use the grinding table a lot.  It is a really big help.

Bob
Bob Sorenson
Harrisburg, South Dakota, USA

Offline xo18thfa

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Re: Harold Hall's precision grinding table
« Reply #30 on: June 01, 2011, 12:33:06 PM »
Hi Wong.  Go with steel for the table top.  The attachments sliding around will wear out aluminum quickly, and make a lot of friction as it scratches up.  There is no tricky machine work on the table top.  I think brass dovetails will work.  Brass is easier to machine.  My mill/drill chattered some when cutting them in steel.  The angle bracket at the bottom could be steel too, or extra heavy thick aluminum.  That part needs to be very rigid.  Aluminum for the rest should work out.  Mr Hall's plans are metric, if you are using inch, round up all the material thicknesses to make the table a bit more "beefy"  A little extra stout will help.

I use the grinding table a lot.  It is a really big help.

Bob
Bob Sorenson
Harrisburg, South Dakota, USA

Offline wongster

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Re: Harold Hall's precision grinding table
« Reply #31 on: June 01, 2011, 07:01:07 PM »
Thanks Bob.  I'm more comfortable with metric.  So his plan is perfect for me  :D

I've ordered the 25mm plastic ball with M6 threads from RDG Tools.  Ordered 2 just in case I screw up.  The tapped holes beneath the table look challenging.  Should I go with thickness of 8mm to make drill/tappping them easier?

Regards,
Wong

Offline Anzaniste

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Re: Harold Hall's precision grinding table
« Reply #32 on: June 01, 2011, 07:12:14 PM »

Wong
Hi, I've just come back to this and I agree with Bob.
Andy
Scrooby, 1 mile south of Gods own County.

Offline wongster

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Re: Harold Hall's precision grinding table
« Reply #33 on: June 01, 2011, 07:22:07 PM »
Hi Andy,

Are you making the same one as Bob or the simpler version that Roy showed in his pic?

Regards,
Wong

Offline Chuck in E. TN

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Re: Harold Hall's precision grinding table
« Reply #34 on: June 01, 2011, 07:33:32 PM »
Just ordered the book. Following this thread closely.

Chuck in E. TN
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Offline xo18thfa

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Re: Harold Hall's precision grinding table
« Reply #35 on: June 02, 2011, 11:06:19 AM »
He's the thread from "wheeltapper" on his table

http://madmodder.net/index.php?topic=2656.0

Hey Wong:  I would just go with Mr Hall's design for the table thickness.  I don't recall it now, but the 1/4" (6mm) I used is plenty good.

Bob
Bob Sorenson
Harrisburg, South Dakota, USA

Offline wongster

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Re: Harold Hall's precision grinding table
« Reply #36 on: June 02, 2011, 12:21:12 PM »
Thank you, Bob,

I just read wheeltapper's.  Nice...

The 3D model was done with the table at 6mm, per the plan in the book.  The description of making the tap holes sounds difficult to me.  I'll give it a shot.  2 projects to finish at the moment for someone.  This will be the 3rd "must do" for myself.

The big countersunk holes are my concern.  Tried on aluminium and steel.  Chatter like no tomorrow.

Regards,
Wong

Offline wheeltapper

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Re: Harold Hall's precision grinding table
« Reply #37 on: June 02, 2011, 02:08:55 PM »
Hi these are what I use for countersinking.


they leave a lovely finish.
they came from Machine Mart but I don't suppose you have any of them.

Roy
I used to be confused, now I just don't know.

Offline wongster

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Re: Harold Hall's precision grinding table
« Reply #38 on: June 02, 2011, 07:07:05 PM »
I have 2 Dormer's.  The only 2 I can find that can fit with into one of the ER16 collets.  One 82 degree and the other 90.

Is there a trick to using countersink?

Just did this a few weeks back.


This is the column bed of the Sherline mill.  After upgrading the major components to achieve bigger work envelope, the leftovers are sufficient to be reassembled with some small purchases to make a manual mill.  Still waiting for the gibs to be sent to me.  The process was uploaded to my blog: http://wongstersproduction.blogspot.com/2011/05/manual-mill-assemblying-from-leftovers.html

Regards,
Wong

Offline Bogstandard

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Re: Harold Hall's precision grinding table
« Reply #39 on: June 03, 2011, 07:17:37 AM »
Slow speed and very fine feed is the recipe that I use.

I find that most countersink tools will chatter if run too fast. They usually have very little clearance on them, so the metal swarf hasn't time to get away before the next cutting face is upon it.


Bogs
« Last Edit: June 03, 2011, 12:28:49 PM by Bogstandard »
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Offline wheeltapper

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Re: Harold Hall's precision grinding table
« Reply #40 on: June 03, 2011, 07:25:10 AM »
Yea, slow and steady wins the race.
I always countersink using the mill, I can control the downfeed better than a drill press.

Roy
I used to be confused, now I just don't know.

Offline xo18thfa

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Re: Harold Hall's precision grinding table
« Reply #41 on: June 03, 2011, 12:30:58 PM »
Slooow speeds on the countersink and oil.  I've also found that doing the countersink cut first with a very small pilot hole reduces chatter.

It is good to ask questions like these and get several answers.
Bob Sorenson
Harrisburg, South Dakota, USA

Offline wongster

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Re: Harold Hall's precision grinding table
« Reply #42 on: June 03, 2011, 08:22:31 PM »
Thanks John, Roy, and Bob.  This will give me the courage to ask another "how to use..." question on using slitting saw.  Will ask in the right thread.

Bob, you mentioned a pilot hole before countersink.  I did the hole first and then apply the countersink to it. Hope I didn't do anything wrong.

Regards,
Wong
« Last Edit: June 07, 2011, 12:37:03 PM by wongster »

Offline Bluechip

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Re: Harold Hall's precision grinding table
« Reply #43 on: June 04, 2011, 05:55:26 AM »
Hi Wong


See if you can get c/sinks similar to these:


http://www.axminster.co.uk/axminster-axminster-chatter-free-countersink-prod21819/

As  others have said, fine feed, low speed & oil. Although I use Rocol RTD fluid on steel.

Despite what they say, it is possible to make them chatter  a bit on stainless, but you have to really abuse them to do it.
Under normal use, they don't chatter at all.

The swarf comes out as a very thin ribbon, which can be very sharp if stainless ..  :( verified by experiment ...  :palm:

Dave BC



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Offline wongster

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Re: Harold Hall's precision grinding table
« Reply #44 on: June 04, 2011, 06:55:18 AM »
Hi Dave,

Thanks. I don't understand what the 3 sizes mean. The max shank size my spindle can take is 10mm.

Regards,
Wong

Offline wheeltapper

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Re: Harold Hall's precision grinding table
« Reply #45 on: June 04, 2011, 07:05:43 AM »
Hi
I think you'll find the sizes refer to the diameter of the countersink.

Roy
I used to be confused, now I just don't know.

Offline wongster

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Re: Harold Hall's precision grinding table
« Reply #46 on: June 04, 2011, 07:44:58 AM »
Hi Roy,

Which is the one for the plastic ball?

Regards,
Wong

Offline wheeltapper

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Re: Harold Hall's precision grinding table
« Reply #47 on: June 04, 2011, 09:53:16 AM »
Hi
I just looked at my rest and the countersink is 17mm diameter.

the biggest one in the above mentioned set only goes up to 15mm whereas my set goes up to 25mm.

I suppose you could get away with 15mm, it should grip enough.

Roy
I used to be confused, now I just don't know.

Offline wongster

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Re: Harold Hall's precision grinding table
« Reply #48 on: June 04, 2011, 11:01:37 AM »
Hi
I just looked at my rest and the countersink is 17mm diameter.

the biggest one in the above mentioned set only goes up to 15mm whereas my set goes up to 25mm.

I suppose you could get away with 15mm, it should grip enough.

Roy

Do you know the size of the shank? Is the included angle the same as on the plan?

Regards,
Wong

Offline wheeltapper

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Re: Harold Hall's precision grinding table
« Reply #49 on: June 04, 2011, 12:51:08 PM »
The countersink on the plan looks to be 20mm dia and 60 degree.
but I didn't worry too much about that.
It's only got to hold on to the ball, it's not that critical. the idea is to make the sinks first then assemble the bits roughly and measure how long the bottom spacer needs to be.

Roy.
I used to be confused, now I just don't know.

Offline Bluechip

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Re: Harold Hall's precision grinding table
« Reply #50 on: June 04, 2011, 01:42:40 PM »
That type of countersink / hole de-burrer or whatever is made larger than 20mm  .. here's a source if you happen to have some Ł140 looking for a new home ..  :scratch:

http://www.engineering-supplies.com/sub/519/countersinks/

The usual included angle for a c/sink is 90 deg AFAIK, except in years gone by when 82 deg was used for 'raised csk.' or 'instrumentation head' screws ..

I don't suppose they would be difficult to make if you just wanted a special. They only appear to be a transverse hole in a bit of round silver steel stock, then machined to a point. Never made one for all that ..

Dave BC


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Offline Bogstandard

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Re: Harold Hall's precision grinding table
« Reply #51 on: June 04, 2011, 02:15:15 PM »
There is a little more to them than that Dave, they actually have a relief grind done on them.

If you look at the very tip, it should be an elliptical type of shape rather than going to a normal point.

I have resharpened mine using a half round Swiss diamond file around the edge of the thru hole, and that seemed to do the trick.

Not bad for a cheapo set of five bought about 10 to 15 years ago.


John
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Offline Bluechip

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Re: Harold Hall's precision grinding table
« Reply #52 on: June 04, 2011, 02:52:03 PM »
There is a little more to them than that Dave, they actually have a relief grind done on them.

If you look at the very tip, it should be an elliptical type of shape rather than going to a normal point.

I have resharpened mine using a half round Swiss diamond file around the edge of the thru hole, and that seemed to do the trick.

Not bad for a cheapo set of five bought about 10 to 15 years ago.


John

Hi John

Another of my illusions gone ... but I'll certainly take your word for it. Did idly look at them when I got them , and wondered how they managed to cut.

But got no further than that.

However, cut they certainly do. I find watching the thin, crinkly ribbon emerging most satisfying ... :thumbup:

Which probably explains the excessive depth of some of my c/sinks ....   :doh:

Dave BC
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Offline xo18thfa

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Re: Harold Hall's precision grinding table
« Reply #53 on: June 04, 2011, 05:37:58 PM »
Thanks John, Roy, and Bob.  This will give me the courage to ask another "how to use..." question on using splitting saw.  Will ask in the right thread.

Bob, you mentioned a pilot hole before countersink.  I did the hole first and then apply the countersink to it. Hope I didn't do anything wrong.

Regards,
Wong

Wongster:  I just drill a very small pilot hole first, countersink then follow up with the full hole.  If you drilled to main hole first, you'll be fine.  Just run slow speed with oil.  You'll be OK.

Those "0 flute" countersinks like someone showed are nice.  I need to get some.

Bob
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Offline wongster

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Re: Harold Hall's precision grinding table
« Reply #54 on: June 04, 2011, 07:31:14 PM »
The countersink on the plan looks to be 20mm dia and 60 degree.
but I didn't worry too much about that.
It's only got to hold on to the ball, it's not that critical. the idea is to make the sinks first then assemble the bits roughly and measure how long the bottom spacer needs to be.

Roy.

That's reassuring enough.  I'll trying using my 90-degree and give it a shot.

Thank you.

Regards,
Wong

Offline wongster

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Re: Harold Hall's precision grinding table
« Reply #55 on: June 04, 2011, 07:39:44 PM »

Wongster:  I just drill a very small pilot hole first, countersink then follow up with the full hole.  If you drilled to main hole first, you'll be fine.  Just run slow speed with oil.  You'll be OK.

Those "0 flute" countersinks like someone showed are nice.  I need to get some.

Bob

Thanks Bob.  I'll try with the pilot hole as suggested.  From the few c/sink holes I did with full hole, the chatter and noise came on the deeper I apply th c/sink enough at very low speed.

Regards,
Wong

Offline wongster

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Re: Harold Hall's precision grinding table
« Reply #56 on: June 07, 2011, 12:39:19 PM »
Hi Wong


See if you can get c/sinks similar to these:


http://www.axminster.co.uk/axminster-axminster-chatter-free-countersink-prod21819/

As  others have said, fine feed, low speed & oil. Although I use Rocol RTD fluid on steel.

Despite what they say, it is possible to make them chatter  a bit on stainless, but you have to really abuse them to do it.
Under normal use, they don't chatter at all.

The swarf comes out as a very thin ribbon, which can be very sharp if stainless ..  :( verified by experiment ...  :palm:

Dave BC


Hello Dave,

Thanks for pointing me to Axminster.  They're great folks to deal with despite my small orders.  The shank size of the 3 piece set has the largest at 10mm; perfect for my Sherline ER16 spindle!

Regards,
Wong

Offline Bluechip

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Re: Harold Hall's precision grinding table
« Reply #57 on: June 07, 2011, 03:07:38 PM »
Hi Wong

I'm surprised you could not get them locally ... I bet they're made in the Far East.

Mine are still going strong, and they've been used a fair bit. But, as Bogs pointed out, it appears they can be sharpened.

Dave BC

 
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Offline wongster

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Re: Harold Hall's precision grinding table
« Reply #58 on: June 10, 2011, 10:26:18 AM »
Hi Dave,

I asked around those shops I frequent due to their proximity. They only carry the type I bought sometime back.  Didn't have a chance to pop by the shop Chan Man Lee that I was pointed to by a kind gentleman of this forum.  Buying on the net and getting it delivered seem the easiest option at this point; been to busy with my work.

Anyway, I'm having my 1st weekend off after 2 months. Hope to have some good quality shop time.

Regards,
Wong

Offline Chuck in E. TN

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Re: Harold Hall's precision grinding table
« Reply #59 on: June 27, 2011, 11:40:10 AM »

I am getting ready to build this rest, using imperial measurements. I have found a few charts on the web listing metric to imperial fasteners, but nothing comparing metric to imperial stock sizes. Anyone got a reference for metal stock sizes for metric to imperial?

Chuck in E. TN
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Offline David Jupp

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Re: Harold Hall's precision grinding table
« Reply #60 on: June 27, 2011, 12:00:16 PM »
Quite a lot of metric sizes in the UK are simply imperial sizes quoted to nearest mm, or sometimes nearest round number of mm.  When we went metric, companies didn't thow away all the old imperial sizing dies.  It's been long enough now that some stock may well be 'genuinely metric' from the start.

Start from these approximations, but think carefully if there are critical design dimensions that need to be 'spot on'.

3mm ~ 1/8"  ;  12 or 13 mm ~ 1/2"  ; 25mm ~ 1"

Offline xo18thfa

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Re: Harold Hall's precision grinding table
« Reply #61 on: June 27, 2011, 12:46:01 PM »
Quite a lot of metric sizes in the UK are simply imperial sizes quoted to nearest mm, or sometimes nearest round number of mm.  When we went metric, companies didn't thow away all the old imperial sizing dies.  It's been long enough now that some stock may well be 'genuinely metric' from the start.

Start from these approximations, but think carefully if there are critical design dimensions that need to be 'spot on'.

3mm ~ 1/8"  ;  12 or 13 mm ~ 1/2"  ; 25mm ~ 1"

That's what I did.  Did not run into any problems.  The only critical dimension is the dovetails.  You can either go "spot on" or "fit the next"
Bob Sorenson
Harrisburg, South Dakota, USA

Offline Chuck in E. TN

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Re: Harold Hall's precision grinding table
« Reply #62 on: July 15, 2011, 08:12:53 AM »
Bob (xo18thfa),

I have a noob question on the dovetails. I had it in my mind that the lower slide was 1" stock, and that's what I got. I've already cut the piece for the lower slide, so I can't return it. My question, if I make the lower slide (drawing 4) from 1" square stock, can I make up the difference with a thicker gib strip? Or do I have to bite the bullet and get bigger stock? I have already completed the slide swivel pieces (drawing 9), except for the dovetail cuts, as I have not received the dovetail cutter yet.
 
Chuck in E. TN
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Offline Chuck in E. TN

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Re: Harold Hall's precision grinding table
« Reply #63 on: July 15, 2011, 10:08:00 AM »
Never mind. Found a block of 2"x2"x3" I'm cutting down now.

Chuck in E. TN
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Offline Chuck in E. TN

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Re: Harold Hall's precision grinding table
« Reply #64 on: July 16, 2011, 12:34:59 PM »
For those that have built this table, I'm a bit confused on the parts that fit to the lower lead screw nut (drawing 16). What is the 6 mm hole at A for?
Also the parts that assemble to the lower slide (drawing 4), what fits in the 12 mm slot? The lower lead screw nut is 9 mm dia.

Chuck in E. TN
« Last Edit: July 16, 2011, 01:46:26 PM by Chuck in E. TN »
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Offline wongster

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Re: Harold Hall's precision grinding table
« Reply #65 on: July 16, 2011, 07:28:00 PM »
Hi Chuck,

Would you be able to post your machining and construction pics when you are building this?  I'll be building one when I finished the 2 jobs on hand.

Thank you.

Regards,
Wong

Offline Chuck in E. TN

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Re: Harold Hall's precision grinding table
« Reply #66 on: July 17, 2011, 07:40:05 AM »
Well, I went back and re-read HH's assembly instructions and figured out the assembly of the lead screws.
Wongster, I'll be glad to take pictures. Haven't taken many yet, I'll get on that today.

Chuck in E. TN
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Offline Chuck in E. TN

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Re: Harold Hall's precision grinding table
« Reply #67 on: July 17, 2011, 10:28:18 AM »
I have posted pics of my progress so far:

http://s571.photobucket.com/albums/ss157/chucketn/Machining/HH%20Grinding%20table/

I don't yet have a dovetail cutter, but have one on order. I have been substituting dimensional metal for what I have in my junk box, and adjusting dimensions as I go. The leadscrews are just 10-24 screws as I have more imperial taps than metric. I only have 2 major parts left to make, the table itself, and the top slide.
I have simplified as much as I can, and probably won't make the fancy locking handles. I simplified the locking screws to bolts with a washer to fit the slots, and loctited them together. I may change my mind later and make the locking screws as HH did. I still have some tuning to do such as rounding the ends of the side arms.
Any comments/suggestions welcome.
I have enjoyed the challenge of this project, and learned a lot in spite of myself! So far, I've burned a couple of cutters, broke one center drill, and spent money on stock that was the wrong size, but still learning a lot.

Chuck in E. TN
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Offline Bernd

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Re: Harold Hall's precision grinding table
« Reply #68 on: July 17, 2011, 12:30:04 PM »
Lookin' good Chuck.  :thumbup:

I'll be building one of those after a couple of projects for two other people and the Shay has all the truck parts made. So it looks likeit'll be well into this years cold season.  :coffee:

Bernd
Route of the Black Diamonds

Offline Chuck in E. TN

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Re: Harold Hall's precision grinding table
« Reply #69 on: July 18, 2011, 09:18:57 AM »
I realize some of the questions I've asked on this build were obvious, but I couldn't see the forrest for the trees. I did convert stock sizes from metric to imperial, but that was an exercise in futility. I have digital calipers and a DRO on the mill. I ended up machining to the metric dimentions most of the time.
I did substitute imperial fasteners as the only metric tap I have is 6mm for the lathe. I ended up cutting most of the parts from larger stock.
So, I'm getting more comfortable with going back and forth from metric to imperial, and my machining abilities are improving. I need to work on learning speeds and feeds as I burned up most of my mill cutters. Motivation to build the milling cutter sharpening jig, huh!
All in all a fun project that taught me a lot. Lathe tool jig, first, drill jig next.

Chuck in E. TN
« Last Edit: July 18, 2011, 06:49:28 PM by Chuck in E. TN »
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Offline DaveH

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Re: Harold Hall's precision grinding table
« Reply #70 on: July 18, 2011, 04:37:52 PM »
Chuck,

Have a look at this - might help a little with the milling.

http://madmodder.net/index.php?topic=4678.msg51465#msg51465

 :beer:

DaveH
(Ex Leicester, Thurmaston, Ashby De La Zouch.)

Offline Chuck in E. TN

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Re: Harold Hall's precision grinding table
« Reply #71 on: July 18, 2011, 07:08:39 PM »
Thanks, Dave, I truely needed that. One of the casualties was a double end mill cutter I inhereted from my late father. Sad loss. It had done many parts when all of a sudden it started spitting out very hot blue chips and I had not changed anything I was doing that I could tell.
I did have a few situations where the vise was not tight enough, and the part was sucked up in the vise and the depth of cut started getting deeper. But, when I started this project, I though I had enough experience with my equipment to know when something was not right. Wake up call!
Can you recommend a set of mill cutters for general purpose projects like we do, including slots, cleaning out for dovetails, etc.? Should I be getting carbide for roughing and HHS for finishing? Should I be using endmills for squaring/cleaning up stock or should I get a face mill?
I have copied your referred post to Word and saved it. I will now sit in the corner and study it...
Thanks again, Dave.

Chuck in E. TN
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Offline DaveH

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Re: Harold Hall's precision grinding table
« Reply #72 on: July 19, 2011, 08:14:14 AM »
Chuck,

Here's a bit on carbide mill cutters - some useful info.

http://madmodder.net/index.php?topic=4861.0


Can you recommend a set of mill cutters for general purpose projects like we do, including slots, cleaning out for dovetails, etc.? Should I be getting carbide for roughing and HHS for finishing? Should I be using endmills for squaring/cleaning up stock or should I get a face mill?
Chuck in E. TN

The above is a really good question, comments and answers could really benifit others.

Would you mind posting your question - say in TOOLS.

This way it should generate a good discussion. It is not that I don't want to answer I will, I just think it is such a good question it deserves a post on it's own.

 :beer:

DaveH
(Ex Leicester, Thurmaston, Ashby De La Zouch.)