Would like help with a Bechler Swiss Cam machine

[JFRISOLI]

I'm a newbie to the site and a machine nut. I bought a Bechler AS-10 Swiss Automatic lathe a few months ago for cheap. Took me 6 weeks to clean it up, check bearings and learn the basics, etc. It's finally up and running after fiddling with the electric components for a week. My main question regards the type of stock I need to run through the guide bushes. I could also use a good source for bushes and collets. Plus I'm sure I'll have many more questions as I begin trying to make parts.
Thanks.

[MikeMc]

The collets and guide bushings can be purchased at Southwick & Meister. The stock will depend ion the OD tolerance of the part you are going to make, and the material itself. If your machine does not have a rotary guide bushing, then you can't do stainless. Paul Huber at Comex has a wealth of information on these machines.

[JFRISOLI]

Thanks for the reply. I'll only be running brass and aluminum, but I can't seem to get the bushing or collet tension correct. And while working in brass the bushing loaded up with swarf and the stock would get jammed up and no longer feed. Any suggestions?

[MikeMc]

Are you sure the chips are what caused the stock to get stuck in the guide bushing? Or was it variance in the stock OD? You can buy Swiss quality brass, and its held to +/- .0005 on the OD. I don'tremember ever seeing chips cause the stock to seize in the GB.

If you run aluminum, always run cold drawn stock, it runs about +/- .002 on the OD, the extruded runs about +/- .005.

[JFRISOLI]

Aha. I think that's the problem. I was not running swiss brass. Can anyone recommend a source for this brass? I'm in NJ.

[MikeMc]

Farmers Copper

[EvansMachine]

On long runs I have had trouble with chips getting built up in the guide bush. This has been mostly with short chipping materials like brass and 12L. Keep your bush clean. You should be able to get normal cold drawn material to work. The tension of your bushing is very important, maybe its a little tight?. I run a tornos enc but more or less its the same concept. Make sure you clean your bars before they go in the feeder. Good Luck

[CarsonD]

On most swiss type machines the tricky part is the guide bushing adjustment and running at the right surface feet.

The material generally needs to be centerless ground to a size that matches the size guide bushing you have. It is usually stamped on the side. Many places now sell precision ground material.

When you set up the machine you need to adjust the bushing just right. If your running something that the tolerances are not that close on you can run it on the sort of looser side. If they are tight sometime you need to snug it down a little more. The thing is if you get it a little to tight it will cause the material to heat up which makes bigger and tighter which makes it even tighter and hotter and the next thing you know it will seize up on you.

There lies the reason for calling them screw machines.


That usually will cause a build up in your guide bushing that needs to be lapped out. That can be accomplished with a lapping compound. Clover brand is made with silicon carbide that will take out the brass, 303, aluminum, or other metal that has built up in there.

Usually this is done on a drill press running at a sort of slow speed. You chuck up a bar end that is the size you are running and coat it with lapping compound. Then it is a matter of lapping out the build up. Sometime you can start with just the bushing itself, doing each pad until it is clean. Often you will want to take your whole bushing sleave out of the machine so you have a way of tightening it down as you work it up and down on the lapping rod to clean it out.

Many times you may find you need to lap out your bushing with a little diamond lapping compound. The diamond will actually cut the carbide in the bushing itself and will resize it to the material you are running.

This is sometime best done on the machine because of alignment. The drawback is contamination of the machine with lapping compound and it needs to be thoroughly cleaned up by removing the bushing.

The surface feet you are running is also important with the heat problem with stationary guide bushings.

With the shaving you described it sounds like there is a mismatch in the bushing and the material size. It doesn't take very much difference for shaving or scratching to happen.

Think about it like a regular collet. If you material is small for the size it is it will bite on the very front of the jaws. If it is big for the size it will bite on the back end of the pads.

It is a very bad thing for guide bushings. Especially in the back as all your support will be far away from your cutting tool... and be cutting and scratching besides.