3C vs. 1A collets

I have a SB model 405 (9") and I'm looking to add some collets. I know the standard collet for this lathe is the 3C, and there are other options such as 5C collets (and others as well) using a collet chuck.

My question is, does anyone know if 1A collets can be used interchangeably with 3C collets. i.e., same draw bar, same MT3 spindle adapter.

They have the same threads (0.645" x 26tpi) and the same body diameter (0.650"), and the only difference I've found is the length (2-11/16" for 3C, 2-9/16" for the 1A), i.e., the 1A is 1/8" shorter.

angle

What about the angle.3AT colletts also have tha same thread,but the sleeve has a different angle.Ie you need a different sleeve.The length can be compensated for with diffefent sleeves at the back end.

k3vyl said:

What about the angle.3AT colletts also have tha same thread,but the sleeve has a different angle.Ie you need a different sleeve.The length can be compensated for with diffefent sleeves at the back end.

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Yes, and you can easily get a 3AT adapter for the spindle.

I think that unless you come across a pile of 3AT collets cheap, stick with 3C. You may already have a closer for that and they are probably more plentiful. If you already have some 3C's, filling out the set is one option vs buying a whole set of 3AT.

I don't think either collet has a technical advantage.

The 5C collet chuck is a nice option, and if you are looking at having to buy a whole set of 3AT or 3C collets, it might not be that much more. 5C collets are cheap and plentiful.

Steve

The differences are slight, but I think the 3C is a better design. It's a bit longer than a 3AT and the angles make more sense. I think 3C was more typical on SBs and 3AT was more typical on Logan. Most of the domestic ones seem to be gone and all you can get new are imports.

1A not 3AT

I have the same question as the OP who was asking about 3C versus 1A.
I have a mixed box of both, and since my lathe is not yet assembled I am not sure they will both work.
Is there any other difference between them besides length?

i don`t know if length is the only difference or not. maybe blue up one of the 1A`s and see how it fits the 3C adapter, if the taper looks good and there is enough length to thread into the closer deep enough, try it??

1A

Just looked it up here at home. The 1A is the SBL version of the 3C collett.It will probably be a better fit on the SB lathe than a 3C.The thread on those colletts is so long that you have room for error.

k3vyl said:

Just looked it up here at home. The 1A is the SBL version of the 3C collett.It will probably be a better fit on the SB lathe than a 3C.The thread on those colletts is so long that you have room for error.

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Thanks for the info k3vyl. I'm the OP. I just returned to this thread after several days and saw the topic got a little sidetracked into a 3AT vs. 3C collet discussion.

At any rate, thanks again. This is the info I was looking for.

Dave

colletts

I have 3C,3AT and 3PN colletts that I use on my 9" and 13" SBLs.Also a few 2As that only work on the 13.Its not hard to make the various adapters once you have the collett in your hot little paw.I make the drawbars out of schedule 80 pipe.

k3vyl said:

Its not hard to make the various adapters once you have the collett in your hot little paw.I make the drawbars out of schedule 80 pipe.

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I'd love to get more info from you on making adapters and drawbars. I'm just beginning the process of getting my 405 equipped with collets. I don't have any parts/pieces yet.

Dave

parts

Some of the stuff I have made is probably less than ideal,but it all works.The schedule 80 pipe requires turning the OD down to get it through the headstock.If you have a follow rest you can get it within a few thou.If you want to buy mandrel drawn tubing you can skip that step.
Probably the easiest thing to make is the spindle nose cap.Mine are both made from bronze scrounged from old valves.The threads are not crytical,and it will give you practice at making internal threads.You will need to make good internal threads in the drawbar.
One of my handwheels is an old valve handle bored out to fit the drawbar.The other one is turned from AL round stock.
Making the collett adapter is a matter of either turning a taper or getting a taper adaptor and boring it out.If you want one with a flange you have to make it from scratch.The tricky part is putting the key in that tapered sleeve.I cheated by using an end mill to start the hole.My adapter is not heat treated,but it seems to be holding up ok.The key is force fitted using a taper,and some careful filing.Filing the inside part is tedious.
Look at all the pictures that you can of these parts and it will help you decide just how you want yours to look.

According to one of the Machinerys Handbooks, information provided by Hardinge, the only difference is the length. The 1A is 1/8" shorter than a 3C and that's it!
I have a mixture of both with my 9" lathe and they all work just fine!

Ken

I have a drawing here that might be useful. No 1A, but if the only difference is 1/8" this should give you a good start. I used both the published numbers and measured a variety of collets from several manufacturers.

this might help, " Collets ".

The site was down when you first posted, so I could not get the link. but it's up now.

Hope this helps.

promacjoe

Conrad Hoffman said:

I have a drawing here that might be useful. No 1A, but if the only difference is 1/8" this should give you a good start. I used both the published numbers and measured a variety of collets from several manufacturers.

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Nice!

After reading several comments here suggesting 1A collets should work fine on my model 405, I bid and won a partial set on eBay. Once I receive them I'll definitely be referring to, and comparing with, your drawing.

Thanks,

Dave