Author Topic: Harold Hall's precision grinding table (Read 54591 times)

xo18thfa · « **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.

wheeltapper · « **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

Corvus corax · « **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

wheeltapper · « **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

xo18thfa · « **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.

wheeltapper · « **Reply #5 on:** March 04, 2011, 01:38:48 PM »

Oh yea. I remember you now.

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

madjackghengis · « **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

xo18thfa · « **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).

Bernd · « **Reply #8 on:** March 13, 2011, 12:54:52 PM »

Looking good Bob.

Real nice job on the dials.

Bernd

xo18thfa · « **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.

sbwhart · « **Reply #10 on:** April 01, 2011, 01:44:11 AM »

Nice neat bit of maching there Bob

Stew

Rob.Wilson · « **Reply #11 on:** April 01, 2011, 02:47:29 AM »

Very nice Bob

Rob

Bernd · « **Reply #12 on:** April 01, 2011, 09:14:18 AM »

Lookin' good Bob.

Bernd

xo18thfa · « **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.

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.

xo18thfa · « **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.

Bernd · « **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

wheeltapper · « **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,

xo18thfa · « **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

wheeltapper · « **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.

xo18thfa · « **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

Ashlyn Katarzyna · « **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!

wheeltapper · « **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

Bernd · « **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

xo18thfa · « **Reply #23 on:** May 26, 2011, 10:50:47 PM »

Quote from: Bernd 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

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

Bob

xo18thfa · « **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.

News:

Author Topic: Harold Hall's precision grinding table (Read 54591 times)

Rob.Wilson