Maching a D1-5 Back Plate

D

ddickey

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Anyone here try to make one?
 
They're not so complicated, spec's are at http://www.tools-n-gizmos.com/specs/Lathe_Spindle_Mount.html - most difficult bit is getting the taper right, both angle and diameter need to be right for a good repeatable mount on the spindle.
The pins are available, but not at all cheap, can be made in the home shop with some determination and care, but need to be a decent grade of steel as they're a) under a lot of stress and b) subject to a lot of wear when changing chucks etc.

A spindle nose, however, is quite a task unless you can get the cams relatively cheaply...

Dave H. (the other one)

(Note: the taper angle of 7*7'30" is as exact as you can get a 1-in-8)
 
Thanks. I have pins already.
Is there a suitable material other than cast iron?
 
The higher end forged steel chuck usually use steel for backplates. In theory cast iron would absorb vibration better but for a chuck backplate it may not make a difference. IIRC one of the main reasons for using CI for backplates is that it's better suited for threaded spindles, to prevent thread galling, the disimilar metals thing.

All steel chucks & backplates usually have a higher RPM rating due to higher strength over CI. And I think I remember reading that steel backplates are better for spindles with nose tapers.

CI backplates are cheap enough that I will just buy them if available for my application. But the steel ones are very pricey! Not sure what type of steel is commonly used though. I've even seen people make backplates out of aluminium but I don't like that idea because of wear characteristics.
 
Never thought about making one out of aluminum.
Why would wear be an issue with a back plate?
 
I was just thinking it would not be a good choice for a backplate. AL is soft, dings easier, not as dense as iron or steel, less rigid. It may not hold up over the years with repeated removal like on the register or threads. As the spindle heats up, the alumn will expand/contract at a much faster rate than steel which might cause issues. CI has a lower RPM rating than steel, perhaps the aluminum might have an even lower rating?

If I were going to spend the time to make a backplate, I'd rather use a material that will last much longer. But I suppose it depends on the size of the chuck & lathe. On a mini lathe with a 3" chuck it may be perfectly fine but probably not a very good idea for an 8" or 10" or larger chuck.
 
Okay,
leaning towards steel at this point.
 
Some options from Speedy Metals.
1117, 1144 stressproof, 41L40, 12L14 & 416 stainless.
Which of those would be the most suitable?
 
I personally would avoid the 416, expensive & not needed in this application. 1144 as well as the leaded alloys just cause they machine really nice. I would say go with whatever is cheapest.
 
ddickey said:
Some options from Speedy Metals.
1117, 1144 stressproof, 41L40, 12L14 & 416 stainless.
Which of those would be the most suitable?
Click to expand...
Tuning in a little late on this.

I would suggest using ductile iron myself. If you'll get me a OD size and a thickness of the slugs needed, I can get a hold of my buddy and see what he has on hand he could ship to me. Or direct ship to you? We be talking about 80-55-06 ductile iron. The stuff cuts nice, not too abrasive.
 
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