5C OR 3C

WHat is the difference so I know what I need?

Hi There,

WHat is the difference so I know what I need?

Click to expand...

The difference between 5C and 3C is basically size. The 3C has an upper limit of 1/2" (I have seen a few 9/16" ones) and 5C has the upper limit of 1-1/8".

The 5C is much more widely used and therefore easier and cheaper to aquire. The 3C was used primarily in the South Bend "Workshop" 9 inch lathes. Collets are less available and therefore more expensive.

The larger South Bend lathes (like the "Heavy Ten") generally use the larger 5C collets. Having said that, it does depend on the spindle size of your lathe. If your lathe has a spindle through hole that is 1-3/8", then your lathe can use the 5C collet. If your lathe has the smaller spindle through hole, then it was intended for a different collet size.

Of course, any spindle can be fitted with a 5C collet chuck. This allows a smaller spindle to use the 5C collet. These collet chucks are expensive. Usually, a set of the proper size collets for your lathe would be cheaper in most cases.

If we knew what size lathe you have, we could advise you as to the correct size collets your lathe would take.

I hope I haven't confused you too much. Good Luck!
-Blue Chips-
Webb

I recently purchase a SB 9C and it came with one collet, nose piece and drawbar. The collet has Piviti 3SB stamped on it and it has 5/8" dia w/ 27 thread pitch on the end of the collet. My questions is, is this a 3C or 5C collet? I would like to purchase a complete set of collets. I am new to owning a lathe. I am inclined to think it is a 3C because of the stamp 3SB.

I also would like to purchase a live center for this, but I do not know what the taper is on the tail stock.

Tailstock should be MT2.

That's not a 5C collet.

gjkozy said:

I recently purchase a SB 9C and it came with one collet, nose piece and drawbar. The collet has Piviti 3SB stamped on it and it has 5/8" dia w/ 27 thread pitch on the end of the collet. My questions is, is this a 3C or 5C collet? I would like to purchase a complete set of collets. I am new to owning a lathe. I am inclined to think it is a 3C because of the stamp 3SB.

I also would like to purchase a live center for this, but I do not know what the taper is on the tail stock.

Click to expand...

That is a 3C collet. You can buy high quality 3C collets from ShopHardinge, they've got anything you could want, both metric and inch, round, square,etc. For that lathe 3C is the way to go, the 5C chuck will take up a lot of space in front of the spindle. One other alternative to going 5C if you want more modern tooling is to go with an ER40 chuck, this will take up quite a bit less space...but again, for that lathe I would go with 3C.

Going purely by the measurements that is not a 3C collet.

3C is more like .640" diameter x 26tpi so recheck those measures.

3C collets have a .640-26 RH thread a body Dia of .650 and a length of 2 11/16

Thank you. Since I already have the draw bar and the accompanying pieces the 3C is what I will go with. These little tid bits of info I am picking up as I go forward.

I think you will choke on what Hardinge wants for a collet.
For 3c you can keep trying ebay or take a look at this:
3C Round Collets, for milling machines
They also carry square and hex 3c collets. Still not cheap
like 5c though.

Larry S