wfrancis
Aluminum
- Joined
- Apr 18, 2012
- Location
- San Francisco, USA
I'm interested in the idea that a lathe with leadscrew can machine a new leadscrew which is more precise (yes, I know that's a problematic word) than the one in the machine when change gears involved.
I know this is a potentially vast subject so I'm going to narrow the scope considerably - I'm interested in the period when the first screw cutting lathes emerged and had hand filed (or via some other primitive method) leadscrews. I'm not (in this query) interested in the 100 methods the Moore company had in making their leadscrews more precise.
I'm including a link below which is one place I have read such a claim. Thiout's lathe is another one which is claimed could make more precise screws than the one in the machine (though via an interesting reducing linkage, not gears).
However, the only way I've been able to noodle that this is possible is if the entire initial leadscrew was uniform, but the pitch was slightly wrong, say 8.1 TPI instead of the desired 8 TPI so, via gearing, you could machine a new leadscrew that was the desired 8 TPI (satisfying "more precise").
While I can't find a source for it now, I believe I've also read the reduction also would average out errors in a non-uniform leadscrew, but to my way of thinking it would reduce the error per turn of thread, but cumulatively the error would still be there.
If anyone has knowledge of this second case and/or relevant literature I'd be very happy to review it.
The Most Powerful Idea in the World: A Story of Steam, Industry, and Invention - William Rosen - Google Books
I know this is a potentially vast subject so I'm going to narrow the scope considerably - I'm interested in the period when the first screw cutting lathes emerged and had hand filed (or via some other primitive method) leadscrews. I'm not (in this query) interested in the 100 methods the Moore company had in making their leadscrews more precise.
I'm including a link below which is one place I have read such a claim. Thiout's lathe is another one which is claimed could make more precise screws than the one in the machine (though via an interesting reducing linkage, not gears).
However, the only way I've been able to noodle that this is possible is if the entire initial leadscrew was uniform, but the pitch was slightly wrong, say 8.1 TPI instead of the desired 8 TPI so, via gearing, you could machine a new leadscrew that was the desired 8 TPI (satisfying "more precise").
While I can't find a source for it now, I believe I've also read the reduction also would average out errors in a non-uniform leadscrew, but to my way of thinking it would reduce the error per turn of thread, but cumulatively the error would still be there.
If anyone has knowledge of this second case and/or relevant literature I'd be very happy to review it.
The Most Powerful Idea in the World: A Story of Steam, Industry, and Invention - William Rosen - Google Books