Newbie custom countershaft 101.07301

[westsailpat]

Yes , the round stock is your lever it should be at least 1/2 , 3/4 would be better and about 6" long . First put the indicator to the top of the chuck , move the lever up and down . Now try it from the side . If you are getting a lot of movement disassemble the spindle . At the area where the bushing is drag your finger nail over the part where the bushing ends , can you feel a step ? Bushings are available form Clausing 800-323-0972 ask for old stuff . Part#'s L9-14 & L2-14 .
Here is a blog on how to disassemble the spindle . It's really not a big deal .
http://www.deansphotographica.com/machining/atlas/spindle/spindle.html

 

[wa5cab]

My original idea was to use some 6” bungee cords to apply tension from the rear of the motor assembly (using as many as needed for the desired tension).

Sorry, but as I wrote a few days ago, both that and using the weight of the motor to set belt tension are bad ideas. If you don't believe it, set your machine up that way. Then mount your 4-jaw chuck and mount a piece of something like 1" aluminum square bar in the chuck. Now try to turn one end down to round. Take a pretty good cut at a slow spindle RPM and watch the motor bounce.

There is nothing wrong with having the motor mount hinged. But tie the other side of the motor down rigidly.

 

[kopeck]

Sorry, but as I wrote a few days ago, both that and using the weight of the motor to set belt tension are bad ideas. If you don't believe it, set your machine up that way. Then mount your 4-jaw chuck and mount a piece of something like 1" aluminum square bar in the chuck. Now try to turn one end down to round. Take a pretty good cut at a slow spindle RPM and watch the motor bounce.

There is nothing wrong with having the motor mount hinged. But tie the other side of the motor down rigidly.

I agree 100% with this. Mine was setup with a purpose build motor hinge and while cutting wasn't an issue the darn thing didn't want to stay in line since all the weight was sitting on one side. I had the hinge setup work on a bandsaw but the belt was a lot longer which helped. If you are going to keep the motor near the counter shaft your room for error is much smaller.

 

[kopeck]

FYI:

Horizontal deflection on my 6" measured on the chuck:

At the backing plate: Slightly less than a half a thousand.
On the working end: Slightly under a thousand.

I do have a indicator that measures in 10th if you want to go that far. I do keep my spindle so it spins easily, the book says it should have a slight drag at slow speeds and be more like I have it setup for high speed turning. I figure if I absolutely need to hit a number I can always snug it up but I want to protect my spindle a much as I can.

K