- Joined
- May 26, 2019
- Messages
- 32
I’m at the thought exercise phase of building a lathe. It’s not because I think it’s the cheapest way to do things or that I think it’ll yield the best machine possible, but because I enjoy the process. I’ve built a wood lathe from wood previously and I’m happy with the result so far. I’m curious to try out the concrete lathe concept that’s out there and see just what’s possible first hand. Maybe it’ll work, maybe it’ll be more a learning experience than a machine build . With a couple kids and limited time, we’ll see when/if I get out of the thought exercise and actually build something...but for now, I have a design question.
The vast majority of lathes I see are designed such that the spindle is located pretty much right between the two ways. Between the radius of the work plus the tool extension beyond the toolpost, this puts much of the downward cutting force on the front way...or pretty much all of it if the downward force ends up in front of the front way. It seems that setting the spindle back somewhat would locate the cutting forces more symmetrically between the two ways, particularly for parts of any appreciable size. This would result in the carriage being forced down against both ways more uniformly during a cut, rather than putting the majority of the load on the front way or potentially even twisting forward (lifting the carriage off the back way in the worst case scenario). Is there a reason moving the spindle back relative to the ways is not more common?
A couple pictures taken from freely available downloadable (old) books (Lathe Design, Construction, and Operation by Oscar Perrigo and Lathe Bed Design by Joseph Horner):
I saw reference to an offset spindle once, but the concept didn’t seem to stick.
Is there a reason it isn’t more common? Or is it more common than I think it is? Thanks!
The vast majority of lathes I see are designed such that the spindle is located pretty much right between the two ways. Between the radius of the work plus the tool extension beyond the toolpost, this puts much of the downward cutting force on the front way...or pretty much all of it if the downward force ends up in front of the front way. It seems that setting the spindle back somewhat would locate the cutting forces more symmetrically between the two ways, particularly for parts of any appreciable size. This would result in the carriage being forced down against both ways more uniformly during a cut, rather than putting the majority of the load on the front way or potentially even twisting forward (lifting the carriage off the back way in the worst case scenario). Is there a reason moving the spindle back relative to the ways is not more common?
A couple pictures taken from freely available downloadable (old) books (Lathe Design, Construction, and Operation by Oscar Perrigo and Lathe Bed Design by Joseph Horner):
I saw reference to an offset spindle once, but the concept didn’t seem to stick.
Is there a reason it isn’t more common? Or is it more common than I think it is? Thanks!