J Grainger
Cast Iron
- Joined
- Oct 12, 2006
- Location
- United Kingdom
Hello,
It seems my Hardinge Splitbed spindle taper is a bit barrelled 2/3rds from the end. I'll hard turn it in place but am unsure how best to set the top slide to the correct angle. The obvious fixation is to try to mimic the best bits of what's there as made by Hardinge, but surely 4 degrees is 4 degrees and bringing back to a specific measurement is better. It seems I can't accurately judge which part of the taper is correct beyond trying to stick a vernier protractor on it.
I have tried setting it to make a backplate and found the spindle taper is getting on for half a thou high in that area. I'm not sure how much error is allowable but know it's way less than this. To set the top slide to true it up I'm thinking that a DTI can be used either..
1) directly on the end of the spindle (ignoring the middle reading),
2) I could turn a straight bar to indicate off (with some messing to remove any taper in the top slide when turning the bar) in brass so it's an easy smooth surface, let everything even in temperature, then set the slide by counting the travel of the DTI along a set travel with the top slide (I don't presently have a 4 degree angle gauge but wouldn't that just add more room for error?).
While the 2nd option seems to have the most potential accuracy in reaching the official 4 degrees I'm concerned that there's more to mess up / accurately measuring top slide travel etc.
Just looking to get some feedback and reassurance to go for option 2 - and I'm not certain what the standard tolerance is on this rate of taper from the factory.
Thank you,
Jonathan
It seems my Hardinge Splitbed spindle taper is a bit barrelled 2/3rds from the end. I'll hard turn it in place but am unsure how best to set the top slide to the correct angle. The obvious fixation is to try to mimic the best bits of what's there as made by Hardinge, but surely 4 degrees is 4 degrees and bringing back to a specific measurement is better. It seems I can't accurately judge which part of the taper is correct beyond trying to stick a vernier protractor on it.
I have tried setting it to make a backplate and found the spindle taper is getting on for half a thou high in that area. I'm not sure how much error is allowable but know it's way less than this. To set the top slide to true it up I'm thinking that a DTI can be used either..
1) directly on the end of the spindle (ignoring the middle reading),
2) I could turn a straight bar to indicate off (with some messing to remove any taper in the top slide when turning the bar) in brass so it's an easy smooth surface, let everything even in temperature, then set the slide by counting the travel of the DTI along a set travel with the top slide (I don't presently have a 4 degree angle gauge but wouldn't that just add more room for error?).
While the 2nd option seems to have the most potential accuracy in reaching the official 4 degrees I'm concerned that there's more to mess up / accurately measuring top slide travel etc.
Just looking to get some feedback and reassurance to go for option 2 - and I'm not certain what the standard tolerance is on this rate of taper from the factory.
Thank you,
Jonathan