Harold Hall advanced grinding rest

Here is the one I got, Was supposed to be updated etc for USA but does not look any diff from others that I have gotten.milling for machinist.jpg
 
Not too much to show, but here's the progress so far. Finished the two dovetailed slide swivel pieces, base plate started and the top slide piece ready to dovetail. Since the top of this piece is one of the bearing surfaces for the dovetail I want to skim it in the same setup as I dovetail it so everything is dead aligned. That only leaves less than 1/8" to hold the piece in a vise which, for my import vise anyways, is a tall order, so I made the piece with extra on each end so I can tie it down to the table, dovetail the sides and skim the top in one setup. After, I'll cut the extra off each end and mill the ends to finish length.

Ted

GR Parts.jpg
 
A little more progress... both dovetail slides done complete with gibs.

I might buy some nyloc nuts for the gib screws but the double locks will have to do for now since they are all I had on hand. I might not even need a locking nut since a single nut might lock the set screw just fine, but Harold suggests either a locking nut or two jam nuts so this is what I'm starting with. If one nut seems to work OK that's what I'll probably end up with. Time and testing will tell.

The two male dovetails gave me a chance to try out the carbide insert dovetail cutter I made. It was too big for the female slides.

Now I've got to do some more CAD work so I can carry on!

Ted

Slides Done.jpgCutting dovetail.jpgDovetail Cutter.jpg
 
Got all the mill work done for now... just have the base angle left to do, but I'm going to change that design a little once I get everything made and assembled to better accommodate the use of the two mag bases. Using them is really sweet on the simpler rest. I'll most likely make a different angle base for the simpler one as well; maybe at the same time since they will probably be similar if not identical.

Pictures of the side arms and spacer/angle blocks below, along with the finished base plate attached to the upper dovetail slide.

Now, a little more Fusion 360 work and move onto the lathe work.

Thanks for the interest,
Ted

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By the way, what steel are you using on this project.
 
kvt said:
By the way, what steel are you using on this project.
Click to expand...

Well, that's a good question on some of it! :) Everything has been on hand and some of it mystery metal. It's really a Heinz 57. Some A36 plate, some 1045 key stock for one of the dovetails, some mystery metal. For the lathe stock it will be some 1020, 1018 and I might make the dials out of aluminum, not sure, maybe steel??? Whatever I have that's around the right size stock. I like using up short pieces when I can. Aluminum is nicer to knurl and scribe the division lines in, but we'll see what I have. I don't have much aluminum around.

I've never been too fussy what material I use on projects unless I have good cause to do so. I did buy some cast iron for the bearings when I made the end mill sharpening fixture since I felt there was a benefit doing so for that application.

Ted
 
I do not have much short pieces around so I was trying to figure out what I wanted or needed to purchase. What I will prob have once I find it is Mystery metal as well. Thinking about just go to the scrap yard and see if I can find anything. Have not even looked a the fixtures yet as have to get a rest made first.
 
I guess as a general guide pretty much any mild carbon would work fine. If buying, some of the free machining stuff would be nice. But, it sounds like you and I have similar thinking with just going to the scrap yard and see what you can find cheap or free. Some of the material I use came off my dad's old farm and has been sitting outside for years... very pitted and rusty. But, once you take the top layer off, it's as good as new! :)

Both my dad and I used to work at a local, now closed, boiler manufacturer Foster Wheeler. They had all kinds of scrap that we both got over the years and some of it was not plain old carbon. They used a lot of high temperature plate, bar stock, etc.. and I still run across pieces of it (non-marked) when grabbing something for a project. 99% of the time I use HSS tooling and when I see the blue chips coming off something I just slow things down and give the material the respect it deserves... It all works fine.

Ted
 
Looks like 3 of us have the same thinking. Pretty much everything I make comes from scrap yard steel of unknown composition too. Unlike you though I can't get any of it for free, around here it's $0.40 / lb for scrap steel. Also like you most of my steel is outside getting that nice brownish color on it.

Once again I follow in your footsteps, as I too have started making the advanced rest. So far just got the main blocks cut and milled to starting dimensions. I'm waiting for some dovetail cutters to arrive from China before I can cut the dovetails. I have a larger dovetail cutter but it's too big for this project. I did get a couple of the leadscrews made too and was dreading making those because it took me forever to make the one for the simple rest. I turned that one with full extension and unsupported. I had to take very light cuts with a sharply honed tool and it was extremely slow going. This time I found a better method, called step turning and that made my day. Weird how sometimes the simplest things get me excited.:)
 
Not sure what size you made your lead screws, but I make mine #10-24.

What I do is make them just a tad longer, put a center in the end and turn the end down smaller than the root of the thread. That way you can use a center in the tailstock to support the piece and you'll have some room for your threading tool at the start of the thread. Then, I put them in a collet and trim that extra end off, or you could just saw it off or whatever.

Or, you could cheat and use a die! o_O

Please keep us posted either in this thread or start a new one,
Ted
 
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