3 Jaw Vs 4 Jaw Chuck

Hi BrayD

The Bison has a A2-5 taper. I suspect your lathe has a D 1-4. From the front it seems to be a plain back chuck with a A 2-5 backing plate (4mounting screws). You would have to make/buy a new D1-4 backing plate for your lathe. Whether you wish to do this is your decision
 
randyc said:
...when this heavy rotary table isn't in use, it is parked on a plywood stand (with casters). This allows me to roll the rotary table along the workbench to the closest location of the mill on which I want to mount it, saving my back from potential damage :)...
Click to expand...

My 12" rotary table must be close to 200 lbs. So I don't want to have to move it far--just lower and move the mill table over far enough to slide it on and off its shelf. I haven't set it up for a chuck yet.

rotary-table-1_zpsjbafceop.jpg
 
ronboult said:
Hi BrayD

The Bison has a A2-5 taper. I suspect your lathe has a D 1-4. From the front it seems to be a plain back chuck with a A 2-5 backing plate (4mounting screws). You would have to make/buy a new D1-4 backing plate for your lathe. Whether you wish to do this is your decision
Click to expand...

Hmm, am I concerned with the taper since it's going on my rotab? So long as it has a flat back and 4 mounting bolts, I should be able to secure it to my 4 slot table via 4 T nuts, correct?
 
Bray D said:
Hmm, am I concerned with the taper since it's going on my rotab? So long as it has a flat back and 4 mounting bolts, I should be able to secure it to my 4 slot table via 4 T nuts, correct?
Click to expand...

It looks like it would bolt to your RT just fine. That looks like a plain back to me, if that's the picture of the actual chuck.
 
I emailed the seller and confirmed that the back is similar to a plain back chuck. It has the taper also, but that shouldn't matter for my application. I went ahead and bought it. Should be here Tuesday. I'll post up pics once I get it unpackaged.

Thanks for all of the insight guys. Much was learned and I'm looking forward to adding another quality piece of tooling to my arsenal.
 
The chuck came in this morning so I ran home during lunch to check it out. It appears to be a nice piece, but I won't know how it checks out until I get an indicator on it.

The whole assembly is tall! I'm sure that will be a blessing for some things - and a curse for others. I need to whip up some t-nuts so I can mount it on my RT. It's just resting on there right now. Head is at max Z in the photo.

IMG_5303.JPG IMG_5304.JPG
 
If you want accuracy and repeatability the 4 jaw independent chuck is the way to go. A 3 jaw scroll chuck not only isn't as accurate, it's meant to be used when all the operations can be done without removing and relocating the piece. Since the 3 jaw has some run out, when you remove and reinsert a part, if the part isn't reinserted in the exact same orientation with the exact same pressure on each of the jaws the part will no longer be on center.

When using a 4 jaw independent chuck the part can removed and reinserted as many times as you like and you'll still be able to center it. I have a number of 3 jaw scroll chucks and a number of 4 jaw independent chucks. The only time I use a 3 jaw scroll chuck is when the part can be finished and parted off the stock with a single setup.

It takes a little time to get used to setting up a part in a 4 jaw independent chuck. Once you are familiar with the process it doesn't take much more time than using a scroll chuck. As mentioned earlier other advantages are being to do an off center setup (as in making a cam lobe), and the ability to grip and hold irregularly shaped stock. The 4 jaw independent chuck is far more versatile, and allows the operator to perform a number of operations that cannot be completed with a 3 jaw or 4 jaw scroll chuck.

If you're only able to afford a single chuck at this time I would definitely make it a 4 jaw independent one. In the long run you'll find you will use it more often than a 3 jaw one, and be able to make accurate parts more easily.

After typing this response I went back to the main page of this thread. The last responses by the OP didn't appear until long after I refreshed the page. Sorry for coming late to the party. It looks like the OP made a wise decision
 
Last edited by a moderator:
projectnut - That wasn't a wasted post by any means. I appreciate the quality response!

I haven't have a chance to try out the 'new' chuck yet, but I hope to in the next couple weeks. I'm building a heavy shelf right now to store the RT and chuck when they're not in use. It seems the majority of my projects have been shop development lately. One of these days I'll have everything arranged so I can settle into some other projects.
 
You must log in or register to reply here.
Back
Top