5C COllet Chuck for Clausing 4914

[echesak]

Hi Folks,

Second post (including the introduction). I have a garage full of machines, one being a Clausing 4914 that I picked up for $150, a few years ago. Other than being fairly greasy, it was in very good shape. I live in the Desert Southwest, so there is rarely trouble with rust. Metal things last forever.

Anyway, I've been using the lathe for various home and work projects, but find that the 3 Jaw chuck is not repeatable in maintaining concentric part clamping. So I was looking for a way to adapt/install a 5C collet chuck to this lathe. It has 1-3/4 x 8 spindle threads. This would help me with my projects considerably. Has anyone done anything similar on a similar lathe, or have an idea of how to do it for a reasonable cost. My preference would be to have something that is ready to thread-on.

As an alternative, I was looking at buying a set of #4MT collets and making a closure clamp. But without the open through hole, it would be somewhat limited.

Any assistance would be appreciated.

Eric

 

[wa5cab]

Eric,

I am going to relocate your thread over to the Clausing forum where there is perhaps a better chance that it will be seen by someone with specific experience. But before I do, I can answer your question in at least a generic way.

There are three ways to run collets on most lathes. I don't have the specs on the 4914 but as you mentioned 4MT collets will assume that is the native internal spindle nose taper. As you already apparently know, you could use 4MT collets and a suitable length drawbar. But that prevents you from running long parts or stock stuck back through the spindle bore.

The second option is to use a collet closer adaptor and drawtube. The drawtube is hollow (although smaller than the spindle bore). The ID of the right end of the drawtube is threaded to match the collet threads. At the left end can be either a handwheel (with no crank) or a lever actuator arrangement. There will be some sort of thrust bearing that sits between the handwheel/lever and the left end of the spindle, probably tapered on its right end to be self centering. The closer adaptor would be 4MT on the OD with an ID to match the specific collet. Or if you are willing to be limited to 1/2" maximum workpiece diameter, you could use a 4MT to 3MT reducer sleeve and use 3AT or 3C collets, adaptor and drawtube. Several of those on eBay this morning, although you would need to make sure before you bought one that the tube was long enough for the spindle in the Clausing. Another possibility would be to use 4C collets, which would give you 3/4" dia. capability but finding the pieces will probably be more difficult. There are also made drawbar and 4MT collet chucks to take 25ER and larger European style collets. But again, the spindle bore is blocked.

The third option you also mentioned, which is a 5C collet chuck to fit your spindle nose. There are quite a number of them available for 1-1/2"-8 spindles. I don't see any on eBay this morning for 1-3/4"-8 but that doesn't necessarily mean that none were ever made. Or you could buy one for 1-1/2"-8 and convert it. I have one of the latter for my Atlas 3996 and like most, it has a removable back plate that might stand modification. Or you could buy a large enough cast iron blank and make a new plate.

And of course if all that this is in pursuit of is to get around the poor repeatability of your 3-jaw chuck, there are the following other possible options:

Use a 4-jaw chuck.
Buy a new (presumably better) 3-jaw chuck
If the problem is your chuck jaws and not the scroll, make the necessary fixture and re-grind the jaws.
Always mark the part with the location of Jaw #1 before removal.

Robert D.

 

[echesak]

Hi Robert. Thanks for the reply and for relocating this post.

All great suggestions - Thanks.

I'm a much better engineer than machinist, so my preference would be to get something that I could just mount-up. With my current chuck, I believe the chuck scroll to be worn, so it is probably due for replacement. For my general work, it is fine, since I'm turning from the raw stock, to a smaller diameter. But on machined parts that need machining on the opposite end or have other operations done and then need to be remachined, A collet chuck would be the fastest and most repeatable. Sometimes I'm machining 20 of the same part. Although a 4 Jaw would work, it would take much longer to remount and recenter the part.

I'll take a look at the 1-1/2x8 chucks and see about having a friend's shop convert it. If I were to convert it, I'd have to mount it to my 3-jaw and would never reach the required concentricity.

In a pinch and for my current project, the 4MT collets would work, but I'd like to find a better overall solution.

Eric

 

[wa5cab]

Eric,

OK. If your current project is 3/4" diameter or smaller, the quicky solution and if it's going to be temporary anyway, probably the cheaper would be to buy a 4MT x 3MT reducing sleeve and buy a set of 3MT collets (or maybe only the size that you actually need). If you only need one size, go buy it from whomever you deal with for machine shop supplies. If you need several sizes, it will probably be cheaper to buy the set. I can recommend those made by CTC Tools in Hong Kong. A set or 11 (1/8 to 3/4 x 16ths) will cost you about $100 delivered. When I bought my set shipping was much lower. Or if you don't need the 1/16th increments, several people sell a smaller set made by Shars which is probably OK The set costs almost as much as the more complete one but shipping is US domestic and much cheaper. If you would prefer to just buy a drawbar, send me the length through the bore of your spindle and I'll tell you whether one sold for the more common Atlas 10"/12" might be easily modifiable to fit.

On modifying a 1-1/2"-8 backplate to fit, the two things to check would be outside diameter and length of the existing hub.

Robert D.

 

[echesak]

Thanks Robert.

I think you're right, the 4MT collets would probably be the fastest, least expensive option. I'd probably just want to make a little cap for the threads, to prevent any accidental damage to them. I'll post an update as soon as I make a decision. Thanks also for the vendor recommendations. I'll check them out.

Eric

 

[wa5cab]

OK. There is one 13-piece Imperial set listed on eBay tonight. About $100 shipped.

Robert D.

 

[pdentrem]

I just did the same thing early this winter. Here is the thread that I started. There are a couple more by others as well.

I used a semi finished backing plate. There is a hole but not threaded. Some times finding a threaded plate seems to hit or miss. I guess it depends on the shipments and popularity of the thread one is looking for.

Anyways for what it is worth, check this out and make more chips.
Pierre

http://www.hobby-machinist.com/show...-threaded-spindle-backing-plates-for-my-lathe

 

[wa5cab]

Eric,

When you get a few more posts and have access, there is an Operating & Parts manual on the 4900 Series in Downloads. Or if you need it sooner, PM me your email address.

What is the swing on the 4900? The manual shows that it came in a 24" and 36" between centers but nothing else. There is no clue in the "14".

Robert D.

 

[echesak]

@Pierre. I figured some had done this before and did a search, but didn't find what I was looking for. Very interesting and helpful thread. Thanks for the link


@Robert: Thanks - I have both these manuals on the lathe. Mine is a 48" bed (10 x 48). I was asking about the manuals at Clausing, and then someone from their service area emailed them to me.

 

[wa5cab]

Eric,

Actually, a 10x48 can't very well have a 48" bed because the headstock and tailstock would each have to be 0" wide. Or to put it another way, a 48" bed is 48" from end to end of the ways. "10x48" means (in the US) 10" dia. swing over the ways and around 48" between the tips of dead centers in the spindle and the tailstock with the tailstock at the right end of the ways and the ram fully retracted. I'm not familiar enough with the Clausing 10" lathes so I'll use an Atlas example. All of the Atlas 9X36, 10x36 and 12x36 lathes have 54" beds. So if the 4900 headstock and tailstock were by chance the same width as those on an Atlas, if the machine is rated 10X48 it would have to have a 66" long bed (5'-6").

Out of curiosity (to judge how likely the one 4900 manual in our Downloads section might be useful to a random owner), what is the serial number of your machine?

Robert D.