G0704 Drawbar nut/wrench - and question...

[kizmit99]

Hi all,
My G0704 mill just has this tiny little stub sticking out of the spindle for tighting/loosening the spindle drawbar:



Since I find myself changing tools very often and that tiny little stub hurts my fingers, I decided to make a larger nut/wrench for the end of it:



My initial testing tells me that this nut is large (and grippy) enough that I'll be able to use it (in place of the 8mm wrench) to tighten and release tooling, so I want to "permanently" mount it. Since that square hole was finished with a file, it's not perfect a perfect fit for the little stub. It's close, but not perfect. I thought I could use set screws on two adjacent sides to keep the nut snug on the end of the shaft. It does work to keep it on, but when I tighten the set screws the nut "lifts" on that side. You might be able to see the unlevelness in this picture:



This leaves the nut at an angle which causes a very visible (and slightly disconcerting) wobble when the machine is running.

Does anyone have any suggestions on how to avoid the lifting I'm seeing when I snug down the set screws? I was thinking maybe try drilling a couple of indents into the stub for the set screws to settle into - but I'm not sure that's the best approach.
Thanks in advance for any pointers...

 

[xalky]

Will that nut clear the head when you lower the quill? My first thought was its gonna hit the head on its way down.

Marcel

 

[kizmit99]

Will that nut clear the head when you lower the quill? My first thought was its gonna hit the head on its way down.

Marcel

Yep - that's not a problem. The quill only extends about 2", and the nut clears the hole in the motor cover:

 

[davidh]

if it were I, a cross hole and a spring pin would be installed.

 

[xalky]

Try putting the set screws on opposite sides, then tighten them in unison.

Sent from my SPH-L710 using Tapatalk

 

[kizmit99]

if it were I, a cross hole and a spring pin would be installed.

You're suggesting a hole all the way through the "stub"? Interesting, I hadn't really considered that because I'm trying to avoid damaging the mill, but that would certainly remove any doubt of the nut slipping off and being hurdled across the shop (which is high on my list of things to avoid).

By "spring pin" are you referring to (what I would call) a roll-pin, or maybe something different?

Thanks for the input!

 

[davidh]

spring pin or roll pin. use the same hole that you tapped but re drill it for the tap diameter. put it on the square end of th shaft, then continue the hole thru the square and the other side of your knob.
have you got the pins ? harbor freight has kits of them cheap.
even easier way is to use a welding rod the same diameter as your drilled hole, squish it in your vice jaws or even use a vice grip plier to squish some marks in it and put it in the hole. you can use a vice grip to squeeze it thru the hole instead of a hammer. gheeze you could have this job done in the time its taking me to type this out with one finger

 

[kizmit99]

spring pin or roll pin. use the same hole that you tapped but re drill it for the tap diameter. put it on the square end of th shaft, then continue the hole thru the square and the other side of your knob.
have you got the pins ? harbor freight has kits of them cheap.
even easier way is to use a welding rod the same diameter as your drilled hole, squish it in your vice jaws or even use a vice grip plier to squish some marks in it and put it in the hole. you can use a vice grip to squeeze it thru the hole instead of a hammer. gheeze you could have this job done in the time its taking me to type this out with one finger

Got it - thanks, I like that idea.

 

[kd4gij]

Here is my salutation It is broached 10mm square and a setscrew holds it on.

 

[John Hasler]

Does anyone have any suggestions on how to avoid the lifting I'm seeing when I snug down the set screws? I was thinking maybe try drilling a couple of indents into the stub for the set screws to settle into - but I'm not sure that's the best approach.
Thanks in advance for any pointers...

Can you slip a bit of shim stock in from the top on the side opposite the screw?