Cross Feed Dial Question

[RVJimD]

Oh boy is this a noob question...

On my G0602/G0729 lathe the cross feed dial goes up to .060" is this a metric screw and .060 is just how it worked out in inches? It seems a bit awkward when I'm Turing something down where I need to remove a bunch. Would be nice if I could count an even number of turns for something like .050" then for say a half inch I could go ten turns and then stop and measure. It is probably because my brain is getting old that sort of try to do the math but then I get about four passes into something like this and forget where I am and stop, measure and then continue. I guess I could try to start using metric, but how do you think my brain would manage that change?

Jim

 

[T Bredehoft]

Uh....060 equals 1.52400 millimeters. Doesn't seem like a reasonable pitch for a metric screw. 16.666 Threads per inch doesn't seem right, either. It certainly isn't 60 mm, can you figure out how the .025 mm figure works out? It sure looks like on mark equals .001, but what pitch is the screw? and is that one on the radius, or the diameter?

I'm no help at all.

Tom

 

[RVJimD]

One tick mark is .001" and one rotation is .060". That is direct feed so that is R, and I always divide by 2 when measuring and turn something down.

The left side indicates .025mm and 60 of those is 1.5mm. So I guess it doesn't do metric or imperial to an even number?

Jim

 

[RJSakowski]

The thread on the lead screw is an M10-1.5mm. A full rotation is 59 thousandths and change. It works out fairly well since you will most likely not cut far enough, check your dimension and finish the cut.

 

[RJSakowski]

On that subject, does anyone know or the thread class? I would like to make a lead screw about an inch longer as the cross feed will not quite make the center line of the spindle. McMaster Carr's threaded rod is all 6g.

 

[mce5802]

On that subject, does anyone know or the thread class? I would like to make a lead screw about an inch longer as the cross feed will not quite make the center line of the spindle. McMaster Carr's threaded rod is all 6g.

Are you using a big enough toolpost and or toolholder for the size of the lathe?

 

[tcarrington]

Having a G0602, I would suggest you carefully check the gibs and their adjustment. If this is a new machine or hasn't have them adjusted, polished or otherwise inspected, you might find them to be rough, binding or otherwise preventing full travel. I found mine to be not quite up to standards - I am being nice.

 

[RJSakowski]

Are you using a big enough too lpost and or tool holder for the size of the lathe?

I have no trouble reaching the center line with the tools. In line with a suggestion made by randyc, I have thought for some time about using the compound protractor for turning spheres. I had actually done that for many years with my Craftsman/Atlas 6". To turn a true sphere, the rotational axis of the compound protractor has to intersect the center line of the lathe spindle. The G0602 runs out of thread about an 1/8th of an inch before. There is no reason not to have a longer lead screw and that is what I was looking to make. An additional inch will allow centering the compound axis and still have the lead screw fully engaged with the lead screw nut.

 

[RJSakowski]

Having a G0602, I would suggest you carefully check the gibs and their adjustment. If this is a new machine or hasn't have them adjusted, polished or otherwise inspected, you might find them to be rough, binding or otherwise preventing full travel. I found mine to be not quite up to standards - I am being nice.

Thanks for the advice TC. It is not a question of binding but rather running out of thread. At 7.0317"inches of travel, the lead screw disengages with the lead screw nut. This is consistent with the specified travel of 6.5"

 

[pdentrem]

What about doing the opposite, make a new lead screw nut that is longer?
Pierre