Saturday, August 4, 2012

Looking at used lathes part 1

So I have been in the market for a engine lathe for my home shop. A couple have come up on Craigslist in the last few months and at a local machinery auction. The first machine I looked at was a nice looking Sheldon R15. Normally Sheldon lathes have a reputation in industry as light duty hobby machines. The Sheldon R series precision tool room lathes are anything but hobby machines.
This particular machine was an R15 and had a long sixty inches between centers.Over all condition was excellent. Unfortunately the owner hadn't bothered to connect electricity to it so I couldn't run it under power. First rule of used machinery buying. Run it under power if you possible can. In the case of an engine lathe you want to be able to run it at its lowest possible speed and at the highest spindle speed. This tests for any headstock problems or odd bearing noises.

This machine came with a good selection of tooling and accessories which is a big plus when machinery shopping. One of the unique features of the Sheldon R series lathes is a tooling slide or positionable compound rest. Normal lathes the compound rest and tool post mount are mounted to a fixed location on the apron. On the Sheldon this mount is actually movable. One of the primary uses of this feature is to attach a second tool post with an additional tool similar to what you see on some Hardinge lathes. The second handy thing you can do is move the tool post to the side away from the operator to cut internal tapers with the compound rest.
You can see in this image how the tool post and compound rest are attached with a dovetail mount which allows you to move it from one end of the apron to the other. Note the large oversize hand wheel dials. The cross feed dial is about six inches in diameter. On this machine it had the optional taper attachment also. It all sound pretty good right?

The negatives on this machine at least for me is the electrical system had been modified. Not necessarily a death warrant, it really depends on how it was done. This machine was retrofitted with a variable frequency drive. Not a bad thing but the devil is in the details. Remember I said there was no power to run this machine? Now I worry a little because I cant fire it up and run it. Looking in the electrical cabinet didn't help my peace of mind.
All the stock Sheldon electrical equipment had been stripped out of the cabinet. Why? The VFD was mounted to the exterior of the electrical cabinet, why junk the stock stuff? The owner gave me a weak answer when I asked about the reasoning behind the decision to strip the electrics. The VFD  installation looked a little kludgy to me so I start wondering what else has been modified?

So over all these things are not necessarily bad things. In fact my over all assessment of the lathe was very good even though I couldn't run it. It was not the machine for me. I went to examine it because it looked pretty good and I know the Sheldon R series of lathes pretty well. The price was okay, not a super deal but not used machinery dealer prices either. This would be a great machine for a larger home shop mainly because of the ability to run the VFD off single phase electricity. My needs and desires are more for a Japanese or European machine with metric threading abilities.

To be continued......

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