Using Riser Blocks on Sherline Lathe

J

j ferguson

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I'm warming up to buying the riser blocks for the headstock, tailstock,and compound for my Sherline 4400. I'm stuck having to make some 4 inch +/- sleeves for a camera lens. Work would be aluminum and there is no good reason to be in a hurry. I'd thought of using the rotary table on my Sherline 2000, but decided I could get a better finish and possibly greater accuracy turning than milling. And of course on the mill, there is the problem of hanging on to the work-piece.

Aside from the obvious care handling a bit bigger chunk of alloy than usual, what should I be watching out for?

If you think this is nuts, it's ok to tell me.
 
You might even consider making some risers yourself- I've made a huge riser for my Unimat when I needed to turn some large discs of plexiglas; and the riser was just a big block of wood with some big c-clamps to fasten the headstock. Worked fine
-Mark
 
interesting idea Mark, but I need to obtain a fairly high level of concentricity between two bores and each needs to be a location fit top the lens if i can do it, but sliding otherwise.

I'm trying to do something Nikon should have done, but didn't.
 
If you have a mill you could do a much more accurate riser than I did, probably at least as good as the Sherline and cheaper
-M
 
markba633csi said:
You might even consider making some risers yourself- I've made a huge riser for my Unimat when I needed to turn some large discs of plexiglas; and the riser was just a big block of wood with some big c-clamps to fasten the headstock. Worked fine
-Mark
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Hahaha, I got laughed T when I suggested this on this forum about a year ago.
Fact is this works and making your own set one day should be a project most small lathe and mill owners should do.
I have seen metal used but I have never seen wood used.
Bridgeport and most of their clones have them available, several of the OEM machine tool manufactures produced and sold them as an option to increase their lathes swing.
The thing that MUST be remembered in this hobby is every cutting situation is different, you need to look at where the forces will be applied and start out slow! Many times just rotating the part at a slow speed for a couple minutes while watching it(stay out of the line of fire!) Or rotating the cutter close but without engaging the material for a minute, during that moment thinking about your machining process you might decide to do something a little differently.
 
sdelivery said:
A wise man once told me that machining is a CONTROLLED COLLISION
Damn if he wasn't right.
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An interesting perspective, to say the least. Years ago (so long I can't remember) I did my model building with a UniMat DB-200. That machine was all ZAMAK castings. Several shortcomings. . . I did make a set of riser blocks, 3/4 inch aluminium as I recall. They functioned well, but it was just another learning experience to me. I only used them a couple of times. I never was into cameras and had very few projects where I needed a set of risers. Edalstall sold a set, so apparently they had calls for them. Aluminium was fine for the UniMat because it was kinda soft anyway. My skills weren't the best then (not to say they're much better now) so the risers weren't much of a problem. And FWIW, you're no more nuts than the rest of us, of any persuasion.

.
 
I hadn't thought this entirely through. The work piece is a 4 1/8 diameter 1 inch 6061. the diameter is approximate because it's what I got cutting this thing on a band saw. So in order to bore the hole and the relief I need to grab it on the outside with a 4 jaw. The Sherline 4 jaw isn't nearly big enough so I need to buy a 4 inch chuck and a 3/4-16 backplate (which amazingly exists) and combine the two. so far so good, then I need to reverse the jaws on the 4 inch chuck to grab the workpiece. And here is where the trouble comes. It looks like it's either naughty or dangerous or both to chuck a piece larger in diameter than the chuck. It isn't much.

Would you do this?

And then there's the cost of all this. I suppose I'll use this setup again, but if I mill this with the rotary table, I won't have to buy anything. Even if I use a 3/8 cutter, it may not finish quite as nicely as it would in the lathe, but only a small part of it will be visible when assembled.
 
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j ferguson said:
I hadn't thought this entirely through. The work piece is a 4 1/8 diameter 1 inch 6061. the diameter is approximate because it's what I got cutting this thing on a band saw. So in order to bore the hole and the relief I need to grab it on the outside with a 4 jaw. The Sherline 4 jaw isn't nearly big enough so I need to buy a 4 inch chuck and a 3/4-16 backplate (which amazingly exists) and combine the two. so far so good, then I need to reverse the jaws on the 4 inch chuck to grab the workpiece. And here is where the trouble comes. It looks like it's either naughty or dangerous or both to chuck a piece larger in diameter than the chuck. It isn't much.

Would you do this?

And then there's the cost of all this. I suppose I'll use this setup again, but if I mill this with the rotary table, I won't have to buy anything. Even if I use a 3/8 cutter, it may not finish quite as nicely as it would in the lath, but only a small part of it will be visible when assembled.
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As long as you have enough thread-engagement on the jaws, I would say it should be perfectly fine. The only other "Danger" I could think of is that if you are going larger than your chuck, you are probably 'oversized' for your lathe (and risk hitting the ways, or not being able to get the RPM low enough for the cut). Additionally, you'd need to make sure you can get to the OD with your cutter.

As far as the riser blocks, A few hunks of aluminum and a small mill, and you could knock them out in an afternoon! The only ones that 'matter' enough to be exact-height is the headstock/tailstock (and then only if you don't have tailstock height adjustment). You might consider milling those in 1 operation, then splitting them as a near-the-end op to make sure they end up reasonably the same height.

Compound is obviously just a 'get close' height, since your tool height is adjustable in the tool holder.
 
As a liability no one can recommend much of anything anymore BUT I see this done regularly on many sizes of machines.
A customer with a 10 meter chuck vertical lathe made some extentions so they can perform just what your talking about.
Yes, I would do it but start slow and top frequently until you are sure your part is staying where you chucked it and remember your surface speed will go up as the diameter increases so slow your spindle down some.
 
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