Improving the RF-30 Mill/Drill Y Axis Take Up Nut

**rgsparber** · Sep 15, 2015, 11:20 AM

You make a good point about O-rings. Maybe I should wait for my Belleville washers to come in... Yes, I would put a washer on each bolt.

Thanks!

Rick

**C-Bag** · Sep 15, 2015, 12:23 PM

Now I'm not trying to second guess you here and I'm an admitted noob....but it seems the Belleville washers would be counter productive on the bolts. They would provide constant pressure if tightened enough to keep the bolts from moving around wouldn't they? There's no difference between them and a split lock washer is there? I thought that's why you didn't want a split lock washer.

To me this is a lot like your solution for the keeping the way adjuster in place. The way the old lead screw adjustment worked was to put back pressure against the clamping pressure of the single screw. But it also caused an uneven angle of pressure. So in my pea brain it seems the bolt heads need to be captured in the cap of the takeup nut, or some kind of compression washer like the Bellville in between the cap and body of the takeup nut. But that might mean it has to be different thickness to get the fit right. And still would need a solution for keeping the bolts from backing out. That's why the striplock appeals to me.

Or am I just like my avatar, just blowing steam and getting nowhere?

**rgsparber** · Sep 15, 2015, 12:48 PM

By comment was misleading. Let me expand on it. Please let me know if this still sounds bogus.

The Belleville washers would go between the body of the take up nut and the movable part. The key is that I must be able to set the backlash and have it stay put. I do not want to crunch down to get zero backlash. That would at best accelerate wear and at worst just bind up. The Belleville washers provide a uniform radial force. The split washer provides a force only at a single point so would tend to tilt the movable part of the take up nut. Ultimately, I want the gap between body and movable part of the take up nut to be fixed.

Rick

**Paul Jones** · Sep 15, 2015, 12:52 PM

C-Bag, I have to agree with your idea of using constant pressure with the cap screws with strip locks or any "give" would defeat the purpose of a constant and predicable gap to remove backlash. In my recent post for using thrust washers to reduce the lathe leadscrew and feed rod lateral play, I had thought about using Belleville washers. However, the extra give from the washers was what I didn't need to happen so I used the thrust washers.

**C-Bag** · Sep 15, 2015, 01:07 PM

Rick, the only part that was not clear was where the washer was going to go, and you cleared that up. My next question is there really enough room between the takeup and the cap? Looks pretty close(between the leadscrew and the bolts) and my experience with Bellvilles is they need to be pretty big in order for the "bell" to work.

I of course agree Paul, we are just working in a lot closer quarters than your excellent fix on the lathe leadscrew.

This all gets so minute and nit picky. Also trying to envision it all without having it right in my hands. There are so many ways to do this, it just all comes down to preference.

I await your final fitting of the washers Rick and see how it comes out. Thanks for keeping us posted. I know this all will help my old RF30 too when I can finally get around to tearing into it.

**rgsparber** · Sep 15, 2015, 01:19 PM

It is rather tight so maybe the Belleville washers won't fit. If they don't, I will likely go with Loctite.

My RF-30 is 25 years old and I've been the only owner. Would not trade it for any other mill.

**C-Bag** · Sep 15, 2015, 01:42 PM

Originally Posted by rgsparber

It is rather tight so maybe the Belleville washers won't fit. If they don't, I will likely go with Loctite.

My RF-30 is 25 years old and I've been the only owner. Would not trade it for any other mill.

yup, Loctite would be the easiest and don't see why it wouldn't work just fine.

My RF-30 was made in '88 and I wish I'd been the only owner. There are some good things about the mill(#1 being buying it for $400), and some real drawbacks as I'm learning. But I don't have the space or the inclination to go any bigger. At this point it's still a better machine than I am a machinist.

best of luck on your fix.