Shopsmith Mark V- broken plastic gear...help!

billtvt · Post by **billtvt** » Sun Apr 03, 2011 7:15 pm

I was trying to use my lathe today and encountered an issue. Basically, I was trying to turn a piece of wood and my chisel grabbed hard and I heard a grinding noise. I shut the machine off, unplugged it and took off the main cover to find that the plastic gear that connects the motor to the drive shaft was broken. So, I have a couple of questions. First- I'm not sure if this is fairly common- I imagine that the part is made of plastic for a reason; to sacrificially break and keep major damage from happening. Second- I'm not exactly sure how this piece fits on. It appears that the mounting arbor needs to come off to allow this piece to fit on, but I'm not sure how that comes off. It looks like there is a snap ring on the topside.. but I would appreciate a bit of direction on this.

I have not had much success on the lathe- my chisels are sharp but more often than not, the piece I try to turn abruptly grabs the chisel and usually knocks the piece out of balance or in this case ...even worse.

BTW- I bought this machine second hand about a year ago. It was very well maintained and hardly used. I am interested in keeping it tuned up and wondering what I should consider for servicing. For example, the belts look to be in good shape, but I have no idea when they were last changed- or if they should be changed.

Appreciate any help.

thanks

JPG · Post by **JPG** » Sun Apr 03, 2011 8:32 pm

[quote="billtvt"]I was trying to use my lathe today and encountered an issue. Basically, I was trying to turn a piece of wood and my chisel grabbed hard and I heard a grinding noise. I shut the machine off, unplugged it and took off the main cover to find that the plastic gear that connects the motor to the drive shaft was broken. So, I have a couple of questions. First- I'm not sure if this is fairly common- I imagine that the part is made of plastic for a reason]

Your description is confusing. Can you post a pix? The only 'plastic' coupling I know of is not visible with the main cover(belt cover?) off.

SDSSmith · Post by **SDSSmith** » Sun Apr 03, 2011 8:45 pm

JPG40504 wrote:Your description is confusing. Can you post a pix? The only 'plastic' coupling I know of is not visible with the main cover(belt cover?) off.

Possibly the drive and ring assembly, part 57, in this diagram.

pennview · Post by **pennview** » Sun Apr 03, 2011 9:17 pm

Please describe what you are turning and which chisels you are using, especially the one that case that crash, and then perhaps we can get to the root of the problem. Of the five chisels in the basic Shopsmith set, the skew is the most problematic. Using the chisels as scrapers is generally easier to begin with and lessens the chances of a serious catch.

spiderclimber · Post by **spiderclimber** » Sun Apr 03, 2011 9:33 pm

I also do not know from the description but how are you using the lathe tools? You may not have the arm rest in the right position which is allowing you to get the tool caught under the piece turning and jam the machine.

Pictures would be helpful, just make sure they are sized right. Picture posting how to is linked below in the new owner thread.

Also for the new owner questions on maintenance there is a good thread located Here

JPG · Post by **JPG** » Mon Apr 04, 2011 1:48 am

SDSSmith wrote:Possibly the drive and ring assembly, part 57, in this diagram.

Possibly(likely) but not 'visible' from belt cover removed.

wannabewoodworker · Post by **wannabewoodworker** » Mon Apr 04, 2011 7:38 am

Well the only plastic piece that comes to mind is the Drive and Ring assembly like SDSsmith mentioned and the retaining ring:

(ITEM 57 & 58)

This can be easily replaced but you have to take the quill assembly out of the machine and access through the hole in the side of the headstock behind the Shopsmith badge/cover. It may be a bit tough to get off due to the retaining ring. The quill will come off if you loosen the allen head setscrew on the top of the headstock which may be filled with a putty compound there by making it difficult to see. A stroll over to the sawdust sessions is definitely in order for you to completely understand the machine and how it is put together and how to maintain it.

I also agree that you might also want to learn how to better turn on the lathe to help you in not "catching" the turning tools while using the lathe.

SDSSmith · Post by **SDSSmith** » Mon Apr 04, 2011 9:48 am

JPG40504 wrote:Possibly(likely) but not 'visible' from belt cover removed.

Possibly he meant the access plate when he referred to the "main cover". Let's not be picky.

garys · Post by **garys** » Mon Apr 04, 2011 12:02 pm

SDSSmith wrote:Possibly the drive and ring assembly, part 57, in this diagram.

Most likely a good guess from the description. This gear has a snap ring to hold it in place on the shaft.
You aren't the first person to break it. I broke mine about two months ago too. It is a cheap part. Shopsmith had it in stock when I broke mine and I had it in my hands two days later.
Replacing it is quite easy. I removed the headstock left side cover and the motor. Then the secret is to pick out the goop on the top of the small hole in the headstock. Under it you find an allen screw that frees the shaft so you can easily slide the shaft out and replace the gear.

dusty · Post by **dusty** » Mon Apr 04, 2011 1:24 pm

I think you might have meant an "inexpensive" part. Too many of these last for centuries to be classified as "cheap".