Milling on the Lathe Slide

[Antman]

Hi Guys,
Well, I have finished my faceplate adapter plate and knurling tool and now I am turning my attention to milling in the lathe. I feel kinda guilty, being unable, at this stage to contribute anything to HMEM but my questions. I am even building tools that I can’t use, e.g. what do you do with a faceplate? One thing at least is on the cards with it … now I can mount a test piece between centres and drive it with my home made dog, so soon I should have the lathe nicely squared up.

I have been offered a Cincinatti Model 3 mill for less than 1/3 the price I would be paying for a new mill like this,
but the Model 3 is a monstrous big thing and I don’t hardly think the floor in my workshop will take its ton or more.

So logistics, finances and that I don’t think my output warrants it, dictates that I should make do with what I have for milling. Now as I make out, there are 2 basic ways of milling on the cross slide, a boring table that moves parallel and vertical to the cross slide or a vertical slide. The vertical slide will probably be easier to make ( how do you jack a boring table maintaining it parallel to the slide and square with the ways? ), but with the little I know, it seems that a table, jacking vertically from the slide, is a more versatile arrangement. Any suggestions?

The other question is toolholding and driving the tools. My 6 lathe spindle speeds range from 2000 to 125 rpm in big steps and by juggling the pulleys around I can get 60rpm also. Nothing like enough, or usable? I like the idea of an ER25 collet set with an MT3 collet chuck, then I will also buy a straight shank collet chuck and attempt a milling spindle with it. More suggestions?

I suspect a lot of you will think I am going about this hobby a### about face but this direction seems the most logical and fun for me.

Thanks yet again,
Ant

 

[gbritnell]

Hi Ant,
To take one question at a time. First the faceplate. If it's a full faceplate and not a driving faceplate, the difference being the driving faceplate is much smaller and is only meant to drive a lathe dog, then you can bolt irregular pieces to it for facing or sizing. It is like a vertical boring mill.
Next is the milling attachment. When I first got my lathe, a 9" Southbend, and no mill, I used my milling attachment quite often. The biggest drawback is that it only clamps to where the compound mounts so it's not extremely rigid. If you don't try to mill something beyond the size intent of the attachment then it's a useful tool.
If I understand your spindle speeds correctly you say you can go from 125-2000 rpm. If this is correct then you have more than enough speed to drive endmills. My Enco mill will only spin up to 1925 rpm and I have used 3/32 end mills in it.
Any type of collet chuck would be fine for holding endmills, that's kind of your option. If you go to Dean's website he has a very nice built article on making a collet holder for a lathe. The nice thing about his is you can use it to hold longer pieces of stock because of the through hole. Here's the link:
http://www.deansphotographica.com/machining/atlas/atlas.html
I hope this helps a little.
gbritnell

 

[Mainer]

If you go the vertical slide route, try to get one that replaces the compound and sits directly on the cross slide. As gbritnell says, even the best of the vertical slides are not very rigid. You need every advantage you can get.

Do you know about http://www.statecollegecentral.com/metallathe/MLA-5.html ? Andy's kits have top-quality castings and are generally quite well thought out.

 

[Antman]

Thanks GB, I really appreciate a master machinist’s reply. The link you mentioned was way above my head, I don’t even understsand what toolholder he is making.

My faceplate is a big one, 200mm diameter, clearing the bed by > 3/4”. I found it cheap, for another lathe and made an adaptor plate to fit the spindle, and bolt it on with M8x1.25 / M10x1 differential studs. I have been finding it very difficult to clamp things successfully to my lil’ ol’ shaper table, so can’t imagine how you get things to stick to a shiny, new faceplate. It has 8 radial slots only 35mm long and a great 40mm hole in the centre but it was all I could get.

I’m taking the weekend out the workshop, but thinking about what I’ll get up to Monday, and I’m thinking boring table first, later maybe a vert slide. I don’t think I will be making one similar to what I’ve found on the web, so have a lot of thinking to do. If I don’t make up my mind up about how to jack a table horizontal to the slide I’m gonna tackle a vert slide, and because I enjoy doing 2 projects at once, will make a start on a ball turning device. Finished the FP mount, knurltool and did some colour case hardening by Fri pm. Workshop won’t see me this weekend.

Thanks also Mainer. For the vert slide I have a casting of the base of a Chee Pee brand XY drillpress vice. I figure I can lap the dovetails and make a screw and nut and table.

Ant

PS: The stuff I am making is rough by your standards, but usable, I think. And I finger-errored on the link to the mill, but I still can’t get the link to work.

 

[gbritnell]

Hi Ant,
You can drill and tap some holes in your faceplate. Just make sure that they are evenly spaced around the diameter (balance). That way you can use small finger clamps to hold your work to the faceplate. As for clamping to a shiny or smooth surface, it's no smoother than the surface on a milling table. If there is some concern about the part possibly sliding on the surface just put a piece of notebook paper under it when clamping. The paper will add a friction surface between the part and the faceplate and keep it from moving. I do this quite often when I clamp a piece with a small surface area into my mill vise. That way I don't have to apply too much force with the vise and the part won't have a tendency to slide.
gbritnell

 

[mklotz]

Another setup option to consider is a sacrifical plate for your faceplate. Perforate it with mounting holes as you need them. When it looks like Swiss cheese, replace it.

Also, having the option to cut into the plate while turning can considerably simplify certain turning operations.