4 jaw chuck mounting

[Terrywerm]

Well......what to do....?

There isn't any way I'm going to be able to afford a new mount muchless a new 4 jaw chuck.

Seems like the consensus is that the drive plate is too thin. I had wondered about that too. What if I was to add a 1/4 - 1/2" plate which would be bolted to the drive plate near the thicker hub? I think next time I'm cutting on the plasma I'll zip out a rig of whatever thickness we're using.

Dan, I am going to be a bit blunt here. Most of us are aware that you are currently looking for work and that money is tight. In situations like that, hobbies need to take a back seat to everything else, so it is understandable that you cannot afford a proper back plate at this time. Be patient and wait until you are working again, at which time the money will not be such an issue. Attempting to use shortcuts may just jeopardize your safety and your future ability to provide for your family. A debilitating injury sustained in your own shop would be a major setback for you and your family. There would be no worker's comp, no insurance to fall back on, no employer to file a lawsuit against. NO WORK, NO INCOME, NO MONEY. Please do yourself and your family a big favor and give up on the idea of trying to rig something up in a questionable fashion. Adding a plate between the chuck and the dog drive plate would do nothing to strengthen that drive plate whatsoever, and would push the chuck further from the plate, increasing the leverage of the chuck on the dog drive plate, decreasing the ability of the plate to handle that chuck. In short, please do not attempt to use that dog drive plate for something that it was not designed to do.

One of the nice things about this hobby is that when money is tight, there are inexpensive facets that can be enjoyed, such as drawing up plans for things to be machined and built once money is no longer an issue. Nothing says that we have to be making chips to enjoy this hobby. My machines are still out in my unheated garage. For the most part they spend their winter getting oiled and inspected regularly to keep away the rust, but run very little. I spend much of my winter free time making plans for the things I can build later. When the warm weather comes I can make chips to my heart's content.

I for one am very glad that you posted this question, hopefully we can head off a potential disaster. I told you I was going to be blunt. You can do what you want, but if you continue with this idea none of us here can stop you. I don't live far from you and we have not yet had the chance to meet face to face, so please don't make our first meeting be for a hospital visit or worse.

The holidays are upon us, keep your family's needs in mind, not your desires regarding your hobby. If you really need to machine something with an offset, requiring a four jaw to get it done, if it is a genuine necessity, let me know. I will come over and pick up the part, go home and machine it, then bring it back to you at NO COST rather than have you take unnecessary chances with your family's future.

 

[woodtickgreg]

Excellent advice Wermie. Well said. Think about this my friend. The werm put a lot of effort into his text to protect you and your family and our friend.

 

[DAN_IN_MN]

Okay guys, Thanks!

I did ask. I didn't think it would have taken this road, but that's okay.

I know I don't know it all. That's what this forum is about.

I'll take you up on the machining if I need something. Can you do metric threads? (I think I asked before.)

 

[Terrywerm]

No, the metric threads I cannot do, at least anyway not beyond what I have taps and dies for. And yes, you did ask, but that's okay, I have no problem answering again.

I almost forgot, but I was going to add earlier that mounting your four jaw in the three jaw is probably safer than trying to use that dog drive plate for mounting your four jaw. I also had another idea since then, and was going to post it here anyway. This might be a better solution yet, inexpensive, and relatively easy to do. Not as good as a proper back plate for your chuck, but a perfectly safe and reasonable work around for your problem. Your lathe more than likely has a morse taper inside the spindle. You should be able to make use of it.

For the sake of this thread, let's assume that the spindle has an MT3 internal taper. You could make a stub that is MT3 taper on the one end, and 1 1/2" - 8 thread on the other (or whatever thread fits the four jaw chuck) end. Mount the chuck on the stub, then insert the stub into the spindle. It would run true and be quite strong, certainly better than using the 3 jaw or using that dog drive plate. For safety sake, you could also drill and tap the MT3 tapered end for a 1/2"-13 drawbar, which you could make to fit your lathe. The drawbar would ensure that the stub could not accidentally loosen up in the spindle.

Let us know what you think of that idea.

 

[GK1918]

Wermie just took the words off my typewritter. Further; I would take any old MT3 male weld up some pipe or something o n it >turn that,
then thread it. Nothing beats turning threading (in the headstock) or between centers. Cant count how many I have made, all because of
mainly freebe plates, chucks, drive plates having different threads. Of out our three lathes, they are all different, doing this I can interchange
chucks whatever, from machine to machine. Example, the GK's headstock is a MT 5 + or - dont know dont care, its got massive threads,
I dont know what, dont care; reason no way I can afford a 4Jaw for that one, it presently it has a 3 jaw $1500 Rhom on it. This way I can
use a SBend 4 jaw. Then again sometimes we simply chuck a chuck mainly cause I cant lift the GK's chuck no more. Its still a common
practice, remembering 'speed kills' ...............................

 

[DAN_IN_MN]

Thanks guys!

What do you think about taking a stub shaft and turning threads on it to fit the current mounting on the 4 jaw. Then I'd have a solid mount that can be mounted in my 3 jaw.

 

[Terrywerm]

Hi Dan. Sorry I did not respond sooner, but I left on Monday morning and did not get back home until about an hour ago. Usually holiday weeks are a little slow, but this week has been busy as can be. 2000 miles in already for the week and I still have to run up to Ashland Wisconsin and back on Friday. And to think that I was supposed to have Friday off. Plant will be down, office will be closed, but we have a load that has to delivered by the end of the week, and I'm the only guy that can load myself, so I got elected.

Back to the subject at hand: Yes!! Machining a stub shaft that is threaded to fit the mount on the 4 jaw, but then long enough to mount into the three jaw would work well also. Way better than the way you have been doing it, and safer too. No comparison to attempting to use the dog drive plate, and machining the stub shaft will take almost no time at all.

I never thought about it before now, but I have such a stub shaft, 3/4" in diameter with a piece at the end that is 1 1/2-8 to fit my four jaw. I made it so that I could mount my four jaw into a boring bar holder on the QCTP. I was able to mount a part in the four jaw and mill a slot in it that way, sort of like a poor man's milling attachment. Since I now have a mill, I no longer have any use for the shaft that I am aware of. If your four jaw chuck has a 1 1/2-8 thread on it, you are welcome to the stub shaft that I have here.

 

[Terrywerm]

Here is a pic of the stub that I have. The larger threaded portion is threaded onto the 3/4" shaft, and the thread is locked with the setscrew. The threaded portion is a copy of the spindle nose on my 10" Logan lathe.



Thought you might be interested in a pic of it, since a picture is worth a thousand words.