My nuts were sloppy

[monte55]

Have you ever tried to improve a working machine only to open a big can of worms and have the machine go down. When I made my 4x4 ft table I used dual 3/4 acme screws on the X axis and two steppers(one on each side) I bought the bronze and a tap to make my own acme nuts.
I wasn't sure what size bit to use so the people told me a .600 was correct
but the closest they had was a .609 bit so I got it. My machine was working
ok with these nuts but I wanted less slop and made new nuts. This time I used a 9/16 bit then bored it out to .585 on the lathe. I don't know why this didn't dawn on me the first time. Now the nuts are much closer but being 1 inch long, any misalignment will cause binding which it did and then the stepper would lose a bunch of steps. I had to realign the entire machine. It took a while but came out well. My acme screws are about 65" long and when turning fast the slop in the nut would worsen the whip of the acme screw and was a little noisy during rapids. Now it's running
very smooth. Sometimes slop can be your friend but I still don't like. If you're interested in the table I'm talking about.........It's on page 2 Home made CNC router table update put on March 2.

[Toysrme]

"There once was a guy named Bob
Who had red spots on his knob,
The dock threw him out and started to shout
Just wipe off the lipstick you slob"
Title reminded me of that lol!

[InspirationTool]

Monte, to "tighten your nuts" you should either be slitting them and adding adjustment screws (making two nuts with adjustable spacing) or deliberately mis-aligning them to take out slop.

Either way, you should be shooting for at best .001" - .002" backlash. Any less and you will wear the nut too fast.

-Jeff

[monte55]

Originally Posted by InspirationTool Monte, to "tighten your nuts" you should either be slitting them and adding adjustment screws (making two nuts with adjustable spacing) or deliberately mis-aligning them to take out slop. Either way, you should be shooting for at best .001" - .002" backlash. Any less and you will wear the nut too fast. -Jeff

Good idea.......I could cut through one side and partially through the other just enough to let it have some give like an adjustable die........drill and tap the alum block it's in and put a set screw to squeeze the nut together to take up slack. I'm about
.005 now with an indicater and pushing and pulling on the gantry. What I found is if the tapped hole is too large the acme screw is allowed to move perpendicular to the nuts axis making it sloppy and noisy from excessive whip.
Thanks again...........Nick

[Netjams]

If it ain't broke dont fix it

[rc-cellar]

[jcc3inc]

Sir,

FYI, you can purchase acme threaded rods and nuts from :

Green Bay Manufacturing Co.
Box56, Two Rivers, WI 54241
920-793-2411

I don't know if they have a wed site or not.

Regards,
Jack C.