View Full Version : 4 Jaw chuck question

01-15-2012, 06:34 PM
Another newb tooling question but how are most 4 jaw chucks mounted. The reason i ask is because i didnt receive a 4 jaw chuck when i bought my 13x36 cholchester but i found this one while surfing. Will it fit my lathe`s spindle...:confused:
I have to order a parting tool holder from this site and figured i may as well add this cause it wont affect the price of shipping muchand its on sale:D ..here is the link



Dr Stan
01-15-2012, 06:40 PM
It all depends on the spindle of your lathe. There are several ways to mount a chuck on a lathe including threaded spindles, tapered spindles, and cam lock. You can take a pic of the spindle nose so we can see what you have.

01-15-2012, 06:55 PM
Your lathe manual should tell you what your spindle mount is. It will be something like
L-0 ( a specific type of mount)
D2 ( a specific type of mount)
1 1/2 x 8 ( a threaded mount )
M4x39 ( a threaded mount )

If you can't locate that in the manual's specification page. tell us the exact model number of the lathe and someone here can look it up.

Just looking on the web at http://www.lathes.co.uk/colchester/page2.html I see it could be one of several sizes, depending on the model.
From that web site:
"Unfortunately, the various sizes of this fitting are easily confused by the inexperienced; the Student and Master both used the L0 (L-zero) size, while larger models used an L1 or L2, (etc.) - and smaller machines the L00."

"D1 Cam Lock nose spindle"


01-15-2012, 07:36 PM
I snapped a picture it looks like its threads with somekind of lock? I didnt get a tool to take that off but i can make something..My lathe is a 13x36 student..Looks like it should be a L0.

http://img690.imageshack.us/img690/7076/img4661q.jpg (http://imageshack.us/photo/my-images/690/img4661q.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

The Link to the 4 jaw that i wanted to buy doesnt give any specific mounting type? Is there a way to find out what type it is?

It does say it comes with mounting bolts. Do i mount it on this then to the lathe?

http://img714.imageshack.us/img714/3716/img4662vw.jpg (http://imageshack.us/photo/my-images/714/img4662vw.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

01-15-2012, 08:02 PM
Best guess is that it is a 'plain back' chuck. They would have specified if it was anything else. A 'plain back' has a slight recess on the back to keep it centered. You typically mount it using an adapter for your spindle such as you show in the picture. The adapter is modified to exactly fit the chuck and is dedicated to that use.

You can buy a chuck with the L0 mount built in, but they are more expensive since they fit a smaller range of machines.


01-15-2012, 08:08 PM
That is a L0.

Buy a good chuck. It is well worth it. You can get used ones from Plaza Machinery. He may even have one ready to go with a backplate on itL


Dr Stan
01-15-2012, 09:39 PM
That is a L0.

Buy a good chuck. It is well worth it. You can get used ones from Plaza Machinery. He may even have one ready to go with a backplate on itL

Yep it's an L0. Good advice on buying a good used chuck as I've had problems with Chinese chucks with improperly heat treated parts that were too brittle and broke.

Lost Creek Machinery and Anderson Tooling are a couple more dependable sources.

01-15-2012, 10:07 PM
That is a L0.

Buy a good chuck. It is well worth it. You can get used ones from Plaza Machinery. He may even have one ready to go with a backplate on itL

http://www.plazamachinery.com/Just an additional note for those not familiar with Plaza Machinery. Joe at Plaza has a good deal more than he lists, so it's always worth asking even if you don't see what you want on the web site.

01-15-2012, 10:08 PM
Like others have said, try to find good used.

KBC does list a Bison 4 Jaw in both 8" and 10" with the mount you need as "direct" (as opposed to some sort of adapter plate for a plain back), so they are available...I suggest you be sitting when you see the price.
Cardon near Ottawa (?) has had similar though slightly later model lathes in the past so they maybe worth a check to see if any tooling was either "left behind" or extra from one of those sales
If you've got an urge to really tool up when you are making these inquiries you could also ask about a collet chuck of the Hardinge/Jacobs/Sjogren style...for me it would be quite far down the list but never hurts to ask and if you come across a bargain/gloat with the correct L0 back and style of collet you can live with...

01-15-2012, 10:29 PM
The adapter plate you pixed may or may not work, but what you need
to mount a plain back chuck is similar. Gotchas include the need to
machine the adapter plate to have an elevated center section "male"
to the inset "female" on the back of the chuck. This should be a near
snap fit so the chuck will be less likely to be jerked out of position by
a jolt. Second gotcha: you will be very lucky if the BCD of the chuck
mounting bolts matches anything on the adapter plate. Diameter of the
adapter plate will need to be large enough for the recess and BCD to
be covered, your pixed plate looks a bit small but might work. For an
idea of back plate costs: http://www.victornet.com/subdepartments/Back-Plates-for-Lathe-Chucks/620.html

These are for Bison, but back/adapter plates are rarely much under $100 for specific mounts such as your L-0
and they assume the machining noted above. Listed plates at Victor are
for Bison and almost certainly will have a different BCD.

Busy Bee has a generic back plate: http://www.busybeetools.com/products/ADAPTOR-FOR-4-JAW-CHUCK.html
but this is clearly for a Chinese 3N1 type chuck mount, worthless for you except as something to bolt to the
back plate in your pix to mate your back plate to the chuck.

01-16-2012, 09:36 AM
Hmmm..Lots of good info here. Know i know what i need but do i really need it..Funds are being stretched as it is. How often do you find you use your 4 jaw?

I can see myself needing it to shorten/balance driveshafts( re grab the yoke end) but i havnt had to do that in awhile. I started out doing it with a pretty crude method that involved angle iron, chop saw and a vise.

The resulting shortened shafts actually spun OK for the offroading we were doing as kids);)

01-16-2012, 09:54 AM
you can get a blank back plate off ebay that you machine up ..

that one you show may work ..
whatever ..it has to be cast iron or you may have problems getting it off after its been on for a while

so...you showed the one you have ...so why not fit it to a chuck that you buy .

to machine a back plate you may need two lathes.

or at least another four jaw to do it in .

keep searching ebay ..the four jaw with the right back plate will turn up ..set yourself a price ..

its going to be cheaper and cost effective to find a brand new chuck and find the bacxkplate seperatly though

you'll soon know if you need it ...the three jaws are inacurate ..especially an old one ..the one on it now may have run out ..lots of run out .

put a nice strait bar in the lathe......turn it down a bit ...loosen the jaws...........turn it say 60 degrees in the jaws ...........then turn it down again withoutr moving the tool post/carrage ..stop half way and observe ..the step

all the best.markj

01-16-2012, 09:59 AM

Your lathe uses an "L" type mount. But, you need to know which one, there are L00, L0, L1, L2. Chances are yours would be the smaller L00 or L0. Googling on chuck mounts should yield charts. By measuring your 3 jaw you could find which yours is.

Worst case, if the backing plate mount of the 3 jaw is removable you could buy a plain back 4 jaw and switch the mounting plate between chucks.

01-16-2012, 11:39 AM
re: do I need it?
A four jaw can be (arguably) more useful than a 3-jaw since it allows you to center work to your exact TIR specification. You can also offset, but I rarely if ever need to do that. Since you already have a 3-jaw, though, and are just starting out it sounds -- you don't NEED it unless you NEED it. Might as well not press it. If you have the funds, it is a valuable purchase that will get used. Guaranteed. If the funds are stretched, there are other ways of working with 3-jaw scroll chucks when better precision is required. For example, you have a turned shaft that needs to be mounted in your chuck for another operation. The two features need good concentricity -- better than your 3-jaw is providing. You can use shims between the chuck jaw and work. Use different combinations of shims on the different jaws as needed until you're there. It will take a while! :) BUT it will work. If you don't need to do it often, it is a viable way to get around a lot of 4-jaw work. At a certain point, I would highly recommend getting to work on the lathe and finding out what you truly could use. Often I have found my pre-machining "necessities" don't match what I find would benefit me when actually doing the work. It is a true learning process in that respect, and all of our work and working methods differ a little. This leads to certain tooling being essential for some and a minor convenience for others. In general, though, most would agree an independent 4-jaw chuck is a tool worth acquiring. I would plan for it in the future, but do not feel the need to stress your budget. Just 2-cents. -Arthur

01-16-2012, 05:27 PM
Toxic, I run a Colchester Bantam. Once I started with a 4-jaw, I never again used a 3-jaw. Ever. I just haven't. No point.

Any inaccuracy in a 3-jaw, and you're forever stuffing fag papers in to centre something.

In any old lousy 4-jaw, you can centre anything with a little more trouble. A good tight smooth 4-jaw means quick easy centreing.

If you have more than one 4-jaw you can have more than one part mounted, one in each chuck. so you can machine a quick mandrel say that you need to hold the end of something you're halfway through.

01-16-2012, 09:16 PM
Seems you allready have a source for a chuck. The problem is getting a chuck mounted up. I have a L-1 spindle on my lathe, and have found that getting a chuck with that typ of mount is a pain. The L-1 mount I have is a Bison, and has the bolt pattern for plain back chucks.

All I have done is get a 1 inch, or close to piece cut at your local metel supplyer, and make your own adapter plate to fit you 4= jaw or what ever chuck you want. I use this method for all my chucks. I think I have seven different chucks, som 3 jaw, some 4 jaw, but they all share the same L-1 mount.

Each and evert time that I accuire another chuck, I just machine a adapter plate to suite. This way, you will loose a bit of bed travel, basicly what ever your plate is in thickness 1,or 1 1/4 inch. I find it much better doing this, than spending my time looking for a chuck with the L- what ever mount on it.

If you check with Bison, you can get the L- type spindle mount, that takes plain back chucks, from that point on, just make your own plate for each chuck, and you only spent the money one L type spindle mount. I have tried in the past with used chucks with L type mounting. I found that the chuck was not as nice as I wanted, or the spindle mount was pretty rough, it was a no win deal. The adapter plate method, I allways get what I want. And really, your only loosing a inch or so.


01-16-2012, 10:29 PM
All I have done is get a 1 inch, or close to piece cut at your local metel supplyer, and make your own adapter plate to fit you 4= jaw or what ever chuck you want. I use this method for all my chucks. I think I have seven different chucks, som 3 jaw, some 4 jaw, but they all share the same L-1 mount.

While that is a perfectly valid way to do things, I chose not to do that because I find it a pain to mount a plain back chuck. My smaller lathe uses plain back chucks and it is such a pain to swap them than I will often user whatever is on the spindle even if it is sub-optimal. It takes several minutes and occasional dropped screws or nuts to swap them. I currently have the ER32 collet chuck mounted in the spindle and will probably use it until I need to hold a bigger piece or an oddly shaped piece.

The thread on spindle, on the other hand, is a breeze to swap. My bigger lathe has bigger (heavier) chucks, and being able to spin them on while they sit in a cradle is a very nice thing. Going from 3 jaw to 4 and back is no hassle.

For me, the convenience is worth it. A good chuck mount system is the chuck equivalent of a QCTP.