Mini lathe -- new cross and compound

[Diy89]

I've been thinking of making a new cross slide and compound for the minilathe. Modeled more or less after a southbend. The question i have is what material should i be using? I was thinking for ease i would use a chunk of cast400 from speedy. Then i thought it might be to soft, but i have a large can of kasenit. Why you might ask is just because. I doubt i'll pick up any more ridgity or ease of angle adjustment. Most likely will loose some height above to, but i dont care. So is cast400 ok or should i be looking at steel?

 

[sssfox]

What do you hope to accomplish by remaking the cross slide and compound?

Do you want something that looks better or performs better or both?

 

[Diy89]

I would like it to perform better. Simpler angle adjustment and more ridged, longer travel. I also would like to have the T slot mounting for the tool post. Again though, this is a "use the machine" type project, not really intending on rebuilding the "wheel."

 

[sssfox]

I'm not familiar with cast400. If it is cast iron, it would work fine.
If it was me, I would use steel, just because that is what I have. Either would be strong enough as long as you don't go too thin above the T slots.

You may be able to find a cross slide that you like and build a carriage to support it that fits your lathe. The whole problem with the 7 x series is that there isn't a lot of room between the bed and spindle center, but I guess you know that.

Steel would allow you to go thinner, but wouldn't add any rigidity.

I guess I'm not much help.

 

[Dunc1]

Model Engineers' Workshop had a series about "Making a Long Cross Slide for the C3 [aka Mini] Lathe" in Issue #144, Nov 2008. The material used was continuous cast iron.

Mike's Workshop also has a project that uses steel
www.mikesworkshop.weebly.com/tee-slot-cross-slide.html

 

[Diy89]

Thanks for the links. I think i'll have a go at it. I have a couple engines that need to be finished first, as well as other things honey-doos.

 

[GWRdriver]

If it was me, I would use steel, just because that is what I have.

All makers of industrial and high-end amateur machine tools have used cast iron for their machine castings. There are good reasons for that. The only variation has been that many makers of better machine tools, Bridgeport is an example, began to use higher strength nickel-iron (Meehanite) castings. 400Mpa is approximately 60Kpsi tensile strength, which is probably overkill for a small machine tool. The Grade 40 (40Kpsi) grey iron would do just as well. Continuous-cast cast iron is a joy to machine.

 

[Diy89]

Ooops. I screwed up on that. I meant to say that i was looking at Class 40 (not 400). When i went to check prices to order i noticed my error. This looks like a cheap enough project for the iron. I will have to get a couple of tool bits, but one can never have enough of those cutting tools, right?