- Joined
- Dec 16, 2014
- Messages
- 85
Hi All. So, I am about to attempt a repair of my South Bend 9A Cross slide screw. The previous owner had performed some interesting upgrades. That I have to fix. I had already planned on and acquired a new 7/16 -10 LH acme replacement. But, now I have another task too.
See the "Upgraded dial". Complete with extra large delrin dial, no way to zero it, and super loose for that smooth feel. You may see my problem all ready.
So, I was all set to attempt replacing the acme section of the screw, but had a setback.... I think the prior owner pressed on the dial somehow in their upgrade. This is the result of somewhat mild pressure using my gear puller to try to remove the dial...
Here's the problem: Oops! Those threads are done!
So. I am pretty sure the original dial is buried under the delrin dial extension and may be salvagable.
So.. My question to you good folks is to sanity check my plan to fix it. I have turned a replacement threaded section to match the part you see sticking out from the dial face above. The diameter of the part is about .313". I have turned my replacement with a 3/4" long tang down to .249 where I plan to insert, loctite (Green) and pin to the main shaft.
Santity Check #1: I am a little concerned that drilling and reaming a .250 whole in the .313 shaft might not give enough meat for strength. Why .250 you ask? Well, I have .250 reamer already, and I thought it seemed like a passable size.
Sanity Check #2: Pin it? I have a .1247 pin reamer that I am going to use to straight pin the new acme section in the other end of the screw. Just worried using a .125 pin in a 0.250 shaft might be too large, or too much? Are there rules of thumb for pin sizing?
Any other words of advice, warning before I jump in? This is step 1 of several fixes for my cross slide. I'm also going to turn a replacement for the mounting boss that attaches in the cross slide, maybe a new dial if needed, and
Thanks in advance for any advice.
See the "Upgraded dial". Complete with extra large delrin dial, no way to zero it, and super loose for that smooth feel. You may see my problem all ready.
So, I was all set to attempt replacing the acme section of the screw, but had a setback.... I think the prior owner pressed on the dial somehow in their upgrade. This is the result of somewhat mild pressure using my gear puller to try to remove the dial...
Here's the problem: Oops! Those threads are done!
So. I am pretty sure the original dial is buried under the delrin dial extension and may be salvagable.
So.. My question to you good folks is to sanity check my plan to fix it. I have turned a replacement threaded section to match the part you see sticking out from the dial face above. The diameter of the part is about .313". I have turned my replacement with a 3/4" long tang down to .249 where I plan to insert, loctite (Green) and pin to the main shaft.
Santity Check #1: I am a little concerned that drilling and reaming a .250 whole in the .313 shaft might not give enough meat for strength. Why .250 you ask? Well, I have .250 reamer already, and I thought it seemed like a passable size.
Sanity Check #2: Pin it? I have a .1247 pin reamer that I am going to use to straight pin the new acme section in the other end of the screw. Just worried using a .125 pin in a 0.250 shaft might be too large, or too much? Are there rules of thumb for pin sizing?
Any other words of advice, warning before I jump in? This is step 1 of several fixes for my cross slide. I'm also going to turn a replacement for the mounting boss that attaches in the cross slide, maybe a new dial if needed, and
Thanks in advance for any advice.
