Blueprinting Jig Question

P

pdhntr

Guest
I was looking at 4" OD aluminum and getting ready to order a foot for building a blue printing jig, and I found a special that was offering a 7 3/4 inch long piece of tube that is 4" OD with a 1/2" wall thickness, for quite a bit less money.

Is the 1/2" wall thickness enough? Or do I have to bore a solid piece?

Thanks.

Jim
 
Having fiddled some with measuring deflection in steel I'll have to opine that 1/2" seems really flimsy to me.

This is just a knee-jerk response.

al
 
I'm confused?

What are you going to do with a 3 inch ID piece?
 
I wouldn't use the .5" wall thickness aluminum "tube", especially if you're going to hold it in a 4-jaw chuck. It will distort. I made mine out of cored steel stock for strength and vibration/chatter dampening. I bolt it to a faceplate that I adapted [counterbored to center & prevent radial movent]. Bolting it to a faceplate rather than holding in a 4-jaw shortens up the "overhang" considerably & eliminates having to center it every time it is set up for a job, although that wouldn't be an issue if a 4-jaw scroll chuck were used or a 3-jaw chuck. A MEAT EATING, GUN TOTING, PINKO COMMIE ATHIEST, LIBERAL DEMOCRAT !
 
Ben Dover;
Would you have any pictures of your set-up that you could post? I would be very interested what you have described for I am looking at building one myself.

Thanks Rick
 
Thanks guys.

I didn't think it would work. Too bad, it was a real good price.

Jim
 
I recently fabricated one myself and I attached it directly to a 6" D1-4 backplate. It's no heavier than my 8" 4-jaw chuck, and I don't have to center it. I believe it will be more rigid than holding aluminum in a 4-jaw also.

I used 3" diameter steel with a 1.5" hole through the center and counterbored a 6" diameter slab of steel for a press fit of the jig. Then welded front and back and finished the slab to fit the backplate just like fitting a chuck. It's pretty stout and as mentioned, doesn't stick out as far from the lathe.
 
I was going to order the aluminum for it, but you guys got me thinkin'.

I will take another look at my backplate, and what I have lying around for steel.

Thanks.

Jim
 
Damn,
How hard are you cranking your screws! My plans show the same size aluminum tubing listed welded to a piece of aluminum plate. The aluminum plate bolts to a faceplate. You ain't hogging metal off the receiver.
Butch
 
Hi Butch,

I can see how that would work. No deflection caused by the jaws.

However, I know I don't have the aluminum plate that would be needed for this, so the cost of the project goes up considerably.

I normally wouldn't be concerned with the $ amount, but with the latest political decisions here in Wisconsin, I'm going to have to start recycling my toilet paper.

It won't be the pretty polished aluminum jig I was envisioning, but I will come up with something.

Thanks.

Jim
 
Butch,
I agree but there is something to be said for mass and that translates to precision. The foundation needs to be right but then I come from precision grinding, not turning. Without some sort of sink to absorb vibration it will end up in the work, I believe this is one reason some have problems with import machinery and chatter. I have considered building one from aluminum but have concerns, I am in hopes that Dover responds with some pictures, and we may all learn something from it.

Sincerely Rick
 
Butch,
I don't plan on cranking down hard on the screws at all, it just seemed like the heavy piece of DOM tubing sitting here would work perfectly and I didn't see anything in aluminum laying around...that's pretty much it.
 
Damn,
How hard are you cranking your screws! My plans show the same size aluminum tubing listed welded to a piece of aluminum plate. The aluminum plate bolts to a faceplate. You ain't hogging metal off the receiver.
Butch

I was thinking the same thing
 
You must log in or register to reply here.
Back
Top