Author Topic: Advanced Grinding Rest (Harold Hall)  (Read 83225 times)

Offline gerritv

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Re: Advanced Grinding Rest (Harold Hall)
« Reply #15 on: August 31, 2014, 05:21:22 PM »
Great to see someone building this, it is on my list. Though I will have to do some adaptations due to not having a milling machine.

You will have to read this from Harold's web site, he made some modifications/enhancements to the mounts. http://www.homews.co.uk/page59.html

Gerrit
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Online Kim

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Re: Advanced Grinding Rest (Harold Hall)
« Reply #16 on: August 31, 2014, 05:26:18 PM »
Yes, thanks for pointing that out Gerrit.  Luckily, I did get those modifications incorporated into my cobbled metric-to-English converted plans!  But its good to point that out clearly to anyone who might want to follow along at home.

Thanks,
Kim

Arbalest

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Re: Advanced Grinding Rest (Harold Hall)
« Reply #17 on: August 31, 2014, 07:11:43 PM »
Good start Kim! :ThumbsUp:

Online Kim

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Re: Advanced Grinding Rest (Harold Hall)
« Reply #18 on: September 01, 2014, 03:14:44 AM »
Thanks for checking in on me Arbalest!

Hi All,
Today, I completed the dove tail slot in the second identical piece and proceeded to drill the holes.

Here I've just drilled and reamed a 3/8" hole where the swivel action will be occurring (the slide action, is of course, the dovetails).


Then I devised a way hold the part vertically, even with the middle section taken out for the dove tail, and drilled & tapped three 8-32 holes, and one 10-32.  The 8-32's are for adjusting the dovetail gibs, and the 10-32 will eventually be used for locking down the swivel motion.


Here's one Slide Swivel Piece completed, and the second one waiting for it's gib adjustment & swivel lock holes.


Thanks for checking in,
Kim
« Last Edit: July 16, 2017, 04:25:57 PM by Kim »

Offline Dave Otto

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Re: Advanced Grinding Rest (Harold Hall)
« Reply #19 on: September 01, 2014, 04:23:27 PM »
Nice progress Kim,

You may get away with the bench grinder ok, will you have the ability to use a diamond dresser to true the wheel? 

Dave

Online Kim

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Re: Advanced Grinding Rest (Harold Hall)
« Reply #20 on: September 01, 2014, 05:25:44 PM »
Thanks Dave,
Yes, that is my thinking.  One of holding block accessories should be able to hold a diamond dresser so that I can get a good true flat.
Kim

Arbalest

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Re: Advanced Grinding Rest (Harold Hall)
« Reply #21 on: September 01, 2014, 06:58:47 PM »
You guys in the USA are lucky, these are freely available over there! I've not seen anything like it over here.  :(

http://www.grizzly.com/products/Heavy-Duty-Tool-Grinder/H7762



Looks ideal to me?  :naughty:

Offline sshire

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Re: Advanced Grinding Rest (Harold Hall)
« Reply #22 on: September 01, 2014, 09:41:10 PM »
Kim
Looking great! I've been threatening to build one but these damn engine builds keep getting in the way.
There is a 5 part YouTube on the HF grinder. Review and mods needed to make it work well.
I tried pasting the link but keep getting an invalid link message.
YouTube search will get you there.
Best,
Stan

Offline mklotz

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Re: Advanced Grinding Rest (Harold Hall)
« Reply #23 on: September 01, 2014, 10:05:54 PM »
Is this it?

<a href="https://www.youtube.com/watch?v=lSi3lucyRQo" target="_blank">http://www.youtube.com/watch?v=lSi3lucyRQo</a>
Regards, Marv
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Online Kim

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Re: Advanced Grinding Rest (Harold Hall)
« Reply #24 on: September 02, 2014, 12:03:35 AM »
That's an interest set of videos.  But making this tool rest should obviate my need to make their tool rests better.  And in fact, it ought to let me get a really inexpensive grinder with the mikey-mouse tool rests like these:

Here's the HF one (1/2 HP with Light):

http://www.harborfreight.com/6-inch-bench-grinder-with-gooseneck-lamp-37822.html

And here's an even cheaper one from Grizzly (1/3 HP):

http://www.grizzly.com/products/6-Bench-Grinder-w-1-2-Arbor/G9717

This is the type of grinder that Harold uses in his design.  Just a basic off-hand grinder which he puts a cup wheel on and mounts to a base with his Advanced Grinding Rest.  And of course, throws the stock mickey-mouse tool rests in the bin.

That's my current plan. I haven't purchased the grinder yet, but I had my eye on that one from HF.  I like the light, and the orange is nice, don't you think? :)

Kim

Online Kim

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Re: Advanced Grinding Rest (Harold Hall)
« Reply #25 on: September 07, 2014, 05:58:53 AM »
I had planned on doing the other side of the dovetails next, but to cut the steel to size, I ended up having to borrow vise off the mill.  And, since the vice was off the mill I decided that this would be a good time to tackle the Table since the vise doesn't open wide enough to hold it anyway.  Sort-a killing two birds with one vise removal :)
 
So, to start the table, I took a ~4" square piece of 1/4" 1018, mounted it carefully on the mill, and squared up the ragged edges.


After squaring it up, I marked it out carefully.


And then clocked it in square on the mill. This time, I had to devise a way to hold it up off the mill table that allowed me to get to all the places I needed to cut.  I was worried that it would take a couple of different setups to reach all the slots, but happily, I devised a single setup  that covered them all.


To cut the 1/4" slots, I started with 7/32" holes at each end.

Then I took multiple passes with a 7/32" 2-flute end mill to cut all the way through for the slot.


After the 7/32", moved to a 15/64" end mill, then finished with a 1/4" end mill.


The reason I did this, instead of just starting with the 1/4" end mill, is that it helped to clean up the stratification lines you get when you have to cut the slot in multiple passes (which, with my little mill, is pretty much a given).  Here you can see the difference between the original, 7/32" multi-pass on the upper left, and the pass with the 15/64" end mill on the lower right.


The next features to add were the 8-32 counter-sink mounting holes.


And finally, I rounded the corners.  I used a 1/2" washer to draw a radius on each corner, then brought it down by eye using the disk sander.


After I cleaned off the layout blue, I realized that the 1/4" slots didn't come out 1/4".  I assumed that the 2-flute end-mill was more accurate than that, but clearly not; the 1/4" bolt won't fit through the slot!  Turns out it was about 10 thousandths under!


So, I set it back up on the mill, clocked it in again, and widened the slots a bit so they are now a few thousandths over 1/4" (instead of under).  I didn't want to go too big, but I need a 1/4" bolt, and the 1/4" guides on the jigs to fit in these slots!

Now the bolts fit beautifully.  And next time, I'll remember to check the size of the slots before I remove the part and not just ASSUME that the end mill is accurate!


Next up will be the other sides of the dovetails.

Thanks,
Kim
« Last Edit: July 16, 2017, 04:26:49 PM by Kim »

Offline ths

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Re: Advanced Grinding Rest (Harold Hall)
« Reply #26 on: September 07, 2014, 10:33:03 AM »
Nice save with the bolt slots, but perhaps you could have used 6mm with no penalty? Great work on this, I'm enjoying following the progress. Hugh.

Offline vcutajar

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Re: Advanced Grinding Rest (Harold Hall)
« Reply #27 on: September 07, 2014, 10:47:27 AM »
Happily following along.  I have Harold's book in which he describes the rest so it is easy for me to follow.

That is strange.  In my limited experience, my slots end up wider than the end mill and not narrower.

Vince

Offline Don1966

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Re: Advanced Grinding Rest (Harold Hall)
« Reply #28 on: September 07, 2014, 02:50:07 PM »
Nice work Kim and I tend to agree with Vince about the cutter. Don't you just enjoy making something useful? You'll be proud of using it.when completed.

Don

Online Kim

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Re: Advanced Grinding Rest (Harold Hall)
« Reply #29 on: September 07, 2014, 04:10:05 PM »
Thanks for the comments Hugh, Vince, and Don,

Yeah, that's what I had generally thought too.  This 1/4" cutter (a new end mill for this project) is apparently undersized.  I got it from Victor Machine. They seem to have less expensive items, so I suppose it should not be surprising.

Thanks!
Kim

 

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