Author Topic: Harold Hall's precision grinding table (Read 54766 times)

Bernd · « **Reply #25 on:** May 27, 2011, 08:30:54 AM »

Quote from: xo18thfa on May 26, 2011, 10:50:47 PM

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.

Bernd

wongster · « **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

Anzaniste · « **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.

wongster · « **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

xo18thfa · « **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

xo18thfa · « **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

wongster · « **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

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

Anzaniste · « **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

wongster · « **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

Chuck in E. TN · « **Reply #34 on:** June 01, 2011, 07:33:32 PM »

Just ordered the book. Following this thread closely.

Chuck in E. TN

xo18thfa · « **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

wongster · « **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

wheeltapper · « **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

wongster · « **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

Bogstandard · « **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

wheeltapper · « **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

xo18thfa · « **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.

wongster · « **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

Bluechip · « **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 ...

Dave BC

wongster · « **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

wheeltapper · « **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

wongster · « **Reply #46 on:** June 04, 2011, 07:44:58 AM »

Hi Roy,

Which is the one for the plastic ball?

Regards,
Wong

wheeltapper · « **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

wongster · « **Reply #48 on:** June 04, 2011, 11:01:37 AM »

Quote from: wheeltapper 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

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

Regards,
Wong

wheeltapper · « **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.

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Author Topic: Harold Hall's precision grinding table (Read 54766 times)