Step by step method for upgrading a lathe cross slide to linear ball rails.

[tonyfoale]

I'm at it again, attacking my long suffering lathe. I previously made several posts about my electronic control conversions, here are some links to the previous posts.

Lathe cross slide conversion to a ball screw

Ball screw and electronic lathe conversion

More on my lathe conversion

Final?????? update to the lathe electronic control

Screwing without screwing up.

Now I want to turn my electronically controlled lathe into a cam grinding machine which requires the best possible accuracy. When you are chasing tenths slide friction is the enemy of precision so the ball slides are primarily to reduce sliding friction to gain accurate positioning. I have a distant friend who is planning something similar so I made a 14 min video to pass on ideas. I thought that it might be of interest to others so here it is.

[DIYer]

Thanks tonyfoale! We've added your Cross Slide Linear Ball Rail Conversion to our Lathes category,
as well as to your builder page: tonyfoale's Homemade Tools. Your receipt:

Cross Slide Linear Ball Rail Conversion by tonyfoale

tags: bearing, cross slide

[olderdan]

Tony I am following this project with interest, the mechanical process of cam grinding I understand but designing the desired profile is beyond me. I am guessing the cams are to exploit the new stiffer crankcases for your race engine you have made.

[tonyfoale]

Tony I am following this project with interest, the mechanical process of cam grinding I understand but designing the desired profile is beyond me. I am guessing the cams are to exploit the new stiffer crankcases for your race engine you have made.

Alan,

I knew this would capture your attention. Grinding with a motorcycle content, how could it not?

I have written some software to synthesise cam profiles given certain inputs and limits. I have also built a setup for testing cams and viewing in slow motion with a triggered strobe light. This is basically an engine shell with a stripped and balanced crank to drive a cam under test. This is belt driven by a 6 hp motor. I have a dummy cylinder with viewing ports etc. Anyway, I want to made cams to the profile calculated by my synthesis software in order to validate (or not) the software. Well the software is only the messenger, the real test is whether I know what I am doing. This may be of interest https://www.youtube.com/playlist?lis...SvlfD6C_oAHYK3

That is reason no.1 for making the cam grinder, no.2 is as you surmise for my own race bikes. There is a no.3 reason. I have a mate down under who wants to make cams for ancient JAPs, these are not available in the average hardware shop. He has a cylindrical grinder that he wants convert along the lines that I plan with my lathe.

For some time I have been thinking about converting my lathe to linear rails on the X axis but it always seemed like too much work until a couple of nights ago when I saw that it could be done very easily as described in the video. I have the slides on order but they are not due until between 27/12 and 19/01. Impatience got the better of me this morning and I did the modifications to the cross slide from the old larger lathe to take the slides. I was able to test fitting and function because I have the same type of slides, only longer, for another project. There is not much more that I can do now until the new slides arrive. There is some work to do on the saddle of the lathe but that would put the lathe out of action, so that also has to wait for the slides. Here are some pix of this morning's work.

Click for full size.

and some of the cam test device

[tonyfoale]

Part 2 is here Fitting linear slides to a lathe cross slide part 2

[marksbug]

Im gladd your still at it tony!! I had thought about doing this but that will never happen. I sold off my old bug, but still have the aftermerket engines (only 1 small distributor drive vw part & 2 vw keys are used) selling the car wasent a issue as I had planed on getting a dragster for my engines...well the local track got sold to a insurance company to use for a parking lot for crashed cars so...Im officaly done racing. but I still have my fun little turbo GM roadster daily driver. even though Im not a GM fan at all. Keep up the great innovations!!

[tonyfoale]

Part 2

[olderdan]

Looking forward to seeing this in action. What is your chosen material for the cams and heat treatment possibly nitrided?. I was spoilt in my employment as we had our own nitride shop and I used it often as it does not distort the parts.

[tonyfoale]

I'm glad you're still at it Tony!!

I'm only 80 so I intend to be at it for a good while longer yet.

[tonyfoale]

Looking forward to seeing this in action. What is your chosen material for the cams and heat treatment possibly nitrided?. I was spoilt in my employment as we had our own nitride shop and I used it often as it does not distort the parts.

I have not decided yet but I am leaning towards an hard facing alloy. Megacycle in the US use that on their cams. I have used this in the past but now there are all sorts of DLC and other coatings available that I will look into. Firstly I will have to convince myself that I can make cams good enough to warrant going further. I have, for a long time, been considering buying or making an HT oven. I even bought some A1 heating wire.

Here is an example of a test cam from 4140 using the X&Y movements on a CNC Bridgeport mill. It measured up fine and I think that my current endeavors should be even better.

Click for full size.