Lathe DRO's

[Marmotjr]

That little digital display that tells us the RPM's is nice, but is it really necessary?  When I'm turning, if the lathe isn't dancing around, it's not too fast.  When I start cutting, I can easily tell if I need to speed up or slow down.   I can tell if I'm at the right speed by looking at the piece and the lathe, not the DRO.   It's nice to have that info if I need to repeat a cut on a similar piece, but I really never look at it other than for S&G's.    Anybody else?

[Eric.]

Agree.  The piece of wood you're turning and the tool you're using dictates the speed, not some meaningless number on a readout.

[wtnhighlander]

But that number can tell you where to start next time you turn the same item. More important in a production environment, I guess.

[thatCharlieDude]

The readout is also nice for beginners learning to turn.

[Marmotjr]

12 hours ago, thatCharlieDude said:

The readout is also nice for beginners learning to turn.

But why would that be?  You don't get on a motorcycle the first time and immediately go 55 mph just cause that's the speed limit.  You start slow, where you're comfortable and work your way up.  Same with the lathe, if you're not feeling comfortable with a cut, slow it down. 

[thatCharlieDude]

2 hours ago, Marmotjr said:

But why would that be?  You don't get on a motorcycle the first time and immediately go 55 mph just cause that's the speed limit.  You start slow, where you're comfortable and work your way up.  Same with the lathe, if you're not feeling comfortable with a cut, slow it down. 

Many of the turning guides and lathe manuals state speeds for certain sizes of wood. Being able to KNOW you're at 400 rpm instead of guessing for a newbie is very nice. The beginner can also start to associate turning characteristics with certain speeds such as your example of not feeling comfortable and then looking at the readout to see what your speed is. 

[Marmotjr]

31 minutes ago, thatCharlieDude said:

Many of the turning guides and lathe manuals state speeds for certain sizes of wood. Being able to KNOW you're at 400 rpm instead of guessing for a newbie is very nice. The beginner can also start to associate turning characteristics with certain speeds such as your example of not feeling comfortable and then looking at the readout to see what your speed is. 

But all blanks are not similar.  A roundish 12" block might turn fine at 1000 RPM, but the book says it should be at 400, and now you're over cutting and getting catches where you should be having a smooth, fast, lite cut.  A 6" lump of burl might be scary fast at 400, and the book says you should start roughing at 800. 

Even as a new turner, I never agreed with those guide lines.  Whoever wrote those guides isn't in my shop, he can't see how the piece is mounted and how it's balanced.  I really think those guidelines should be removed from the books, and instead they should preach the idea of always starting the lathe at the lowest speed and turning it up till your at a comfortable speed.   

I know the guides were originally written for lathes that had belts you had to switch to change speeds, so it's nearly impossible to ease your way into a speed.  But those lathes don't have (or don't require) DROs.  There was a little chart on the lathe itself that would show you the speed for the various belt settings.   DROs are usually placed on lathes that are variable speed of some sort (Reeves or digital).  These are the lathes one should be easing into the proper speed, and guidelines can be 'ignored' here, as you don't know what the proper speed is until you get there. 

[thatCharlieDude]

That's why they're called guides - to guide you or give you a starting point. Even after just 8 months of turning I have a pretty good idea what speed I'm turning at by look. BUT when I first started using our lathe I wasn't too sure at what speed I was turning at even after following the directions for manually changing the speeds. A readout would have been great. 

[Eric.]

Technically you should always be turning a blank as fast as you safely can.  Which is why numbers don't mean anything.  Like Thad said, every piece of wood is different...you'll turn a straight-grained walnut spindle much faster than a burl bowl blank.  What that speed should be is determined by its size, its structural integrity, and how the lathe and your tools are responding to the wood.  All a newbie needs to know is to start slow and increase speed as needed until you're getting the right cut.  If your lathe is shaking or you're risking an explosion with a questionable blank, you're too fast.

[Marmotjr]

For the record, I'm pushing this as merely a 'philosophical' discussion, so if it seems I was pushing a little hard @thatCharlieDude, it was merely for the sake of argument. 

[thatCharlieDude]

Just now, Marmotjr said:

For the record, I'm pushing this as merely a 'philosophical' discussion, so if it seems I was pushing a little hard @thatCharlieDude, it was merely for the sake of argument. 

I didn't take it that way, in fact I think we're making the same argument from different points of view. I agree that a RO is not necessary and may even be frivolous. But for me, if somebody offered to give me one I wouldn't turn it down. 

[wtnhighlander]

 

 

...faster than a burl bowl blank. 

 

Betcha can't say it fast as you turn it!

[Marmotjr]

16 hours ago, thatCharlieDude said:

I didn't take it that way, in fact I think we're making the same argument from different points of view. I agree that a RO is not necessary and may even be frivolous. But for me, if somebody offered to give me one I wouldn't turn it down. 

Oh yes, gizmos are cool, but not often needed.