"C" Headstock - Introduced in 1991

barbandrob · Post by **barbandrob** » Tue Jun 10, 2008 10:24 pm

In 1991, according to the SS website, the model 510 was introduced with the "C" headstock. The website doesn't elucidate on the difference between this headstock and the one used previously on the 510. Does anyone know the difference? Also, other than the red emergency shut-off switch on the front of the unit, can anyone tell me if there are any other advantages to buying a post-1990 machine (other than the obvious fact that they are newer)?

Thanks for any help,

a1gutterman · Post by **a1gutterman** » Tue Jun 10, 2008 11:05 pm

That sounds like a Bill Mayo question, or Nick.

billmayo · Post by **billmayo** » Tue Jun 10, 2008 11:47 pm

I believe the new rocker switch in the "C" is still just an ON-OFF switch the same as the earlier toggle ON-OFF switch. The new capability is the ability to remove the red switch key to prevent anyone like a child from turning on the Shopsmith. This is more difficult to do with a toggle switch.

An emergency ON-OFF switch will normally have a large red paddle that an leg, arm or hand can quickly shut down the operation of the equipment. Many Shopsmith owners have installed such a switch in different locations where the switch is easy to see and hit.

The "C" headstock has a larger access hole and prettier Logo cover. The older "B" headstock has a smaller access hole with projections on the sides of the access hole for the Logo cover guides to fit in. These projections are hard on larger hands when hooking or unhooking the retaining loop on the quadrant. I end up with several small scratches each time I put my my hand inside a "B" headstock. For this reason, I like the "C" headstocks. Internally, there is little difference in parts other than the switch and logo cover. The other parts are interchangeable between the 2 headstocks. Shopsmith has made small improvements to things like the Drive Sleeve Assembly and the eccentric bushing but I have no idea when these changes were made.

barbandrob wrote:In 1991, according to the SS website, the model 510 was introduced with the "C" headstock. The website doesn't elucidate on the difference between this headstock and the one used previously on the 510. Does anyone know the difference? Also, other than the red emergency shut-off switch on the front of the unit, can anyone tell me if there are any other advantages to buying a post-1990 machine (other than the obvious fact that they are newer)?

Thanks for any help,

barbandrob · Post by **barbandrob** » Wed Jun 11, 2008 1:32 am

You're awesome, Bill. That helps a lot. One day, I'll have all this straight in my head and will actually be educated enough to BUY one without so much angst.

Much thanks,

Nick · Post by **Nick** » Wed Jun 11, 2008 10:18 pm

Great summary, Bill -- I learned a few things. Barb, if you're looking for a used Mark V an want to know how to evaluate a pre-owned machine, you're going to want to see this coming Sawdust Session.

With all good wishes,