Sieg C3 Lathe 7x14 Mounting either a 4 or 5 Inch 3 Jaw

[wmgeorge]

In case you guys missed the memo a few pages ago... I have the 4 inch 3 jaw with plate ordered from LMS.

[old mart]

As I mentioned earlier, I modified the register of a 100mm 4 jaw independent and drilled the body for front mounts to match the pcd of the spindle flange, an easy job, no adaptor required.

[Mike Burch]

BCRider is right. The Sieg C3 lathes (i.e., the 7x machines) do not have an adaptor plate per se, but rather a flange which is part of the spindle and acts as a register.

The C3 comes as standard with an 80mm three-jaw chuck having a recess in the back that fits directly over that flange. Sieg's optional 100mm four-jaw chuck comes with an adaptor plate having the recess for the spindle flange on one side and a larger register to fit the wider recess on the back of the four-jaw on the other. That adaptor plate will possibly fit a standard 100mm three-jaw chuck as well, inasmuch as the register sizes should be the same. The bolt holes for the chuck may be different, but that's an easy enough problem to solve.

[RB211]

Thanks, that confirms that.

Wmgeorge, I'm sure you're not the first to want to fit a 4" 3 jaw onto your minilathe. What does the Great Mini Lathe Modifications Collective out on the web have to say on this?

I made a zero settable chuck back plate for a Bison 4 or 5" chuck that eventually went to Sid when gave him my South Bend 9c. The mini-lathe I had was the Micromark 7x14. Replaced by the before mentioned South Bend. It can be done, it's just a simple flange that you can add adapter flanges to. I still have that backplate I made, its a huge round chunk of 12L14.

[BCRider]

I believe the first of these type of lathes only had a 10" bed.
BC, that's right about the spindle flange, with the use of another lathe, a 100mm 4 jaw independent is easy to modify.

Thanks, that confirms that.

Wmgeorge, I'm sure you're not the first to want to fit a 4" 3 jaw onto your minilathe. What does the Great Mini Lathe Modifications Collective out on the web have to say on this?

[J Tiers]

Nope no more shop tools. Trying to downsize and realized that 3 inch 3 jaw was limiting what use I had of the lathe. The 4 jaw I have is 4 inch but can not find the adapter plate?? Did all those 4 inch 4 jaws need a plate??

Do you have the other set of jaws (or maybe separate reversible top jaws)?

Because with the OD holding jaws, you can hold up to fairly close to the chuck diameter with no jaws sticking out, and all the way to it with a reasonable stickout. Really make smaller chucks more useful.

I tend to notice that myself, because only one of the 3 jaw chucks has both sets, and I had to swap to the 4 jaw for larger work just to get the holding capability before I got that one.

[wmgeorge]

Nope no more shop tools. Trying to downsize and realized that 3 inch 3 jaw was limiting what use I had of the lathe. The 4 jaw I have is 4 inch but can not find the adapter plate?? Did all those 4 inch 4 jaws need a plate??

Well I checked my machine and the 4 inch, 4 jaw I purchased a few years ago, did not need a backing plate. 4 Holes in lathe plate lined up with the 4 on that chuck? Ok thats great.

[old mart]

I believe the first of these type of lathes only had a 10" bed.
BC, that's right about the spindle flange, with the use of another lathe, a 100mm 4 jaw independent is easy to modify.

[BCRider]

I thought all the 7x lathes have an integral backing plate as part of the spindle? And the chuck body itself ends up needing to be sized to the step on it and mounting holes drilled and tapped?

[wmgeorge]

Nope no more shop tools. Trying to downsize and realized that 3 inch 3 jaw was limiting what use I had of the lathe. The 4 jaw I have is 4 inch but can not find the adapter plate?? Did all those 4 inch 4 jaws need a plate??

[Mike Burch]

The Sieg C3 7x14 which I sold three years ago had an 80mm (3") three-jaw and a 100mm (4") four-jaw. Both were fine for that little lathe, but yes, the problem of the sticking-out jaw was occasionally a nuisance. I know that I was tempted to get a 5" chuck until I realised that the jaw stick-out would be even more of a problem.
The sad fact is that it's just a small lathe, and a perfectly fine one if used within its limitations. Eventually you'll get something a bit bigger and gruntier. Maybe next Christmas?

[The Metal Butcher]

I remember with motor oil and old wipers I oiled the bridgeport about every 2 hours. With good wipers and vactra, about once every 8, and it generally doesn't really need it.

[J Tiers]

I remember on Mini-lathe.com where their beginner guide said to use motor oil for way oil. I guess you really do want that detergent to cling all the metal particles together and suck them in under the ways which most likely aren't even making proper contact for the majority of the surfaces.
I stopped going there after I rear that.

And way oil does NOT do that? Ummmm..... YES IT DOES, at least to the same degree that the other il would. Neither really "cling particles together", they are just sticky and hold the particles so they do not slide off the ways.. The detergent part of the motor oil acts on smaller particles anyhow. And 30wt oil is available in non-detergent, which is also used in motors and would be "motor oil". I used that on ways before getting a gallon of Vactra.

[BCRider]

To be fair on a flat surface like that the swarf is going to stay mixed in with non detergent oil as well. The only proper course of action is to fit the carriage with functional wipers.

I say "functional" wipers because I've seen too many soft plastic wipers even on new machines that are not even in contact with the bed ways. They aren't "wipers" but "hover'ers"....

[RB211]

I remember on Mini-lathe.com where their beginner guide said to use motor oil for way oil. I guess you really do want that detergent to cling all the metal particles together and suck them in under the ways which most likely aren't even making proper contact for the majority of the surfaces.
I stopped going there after I rear that.