Reversing Lathe Rotation

My oneway 24X36 has a groove cut in the spindle, both inboard and outboard, and there is generally two setscrews on everytthing I put on the spindle. Never had a problem.

Regards, Lewis

Do you power sand? If so, the "benefits" of reversing diminish to null, as the benefits of _not_ hand sanding grow.

Won't see me going back to hand sanding anything I can use a disk on.

Leslie, I just spin my stronghold chuck snugly against the shoulder of the spindle to sand OR turn items in reverse. Have a look here..............

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M.J. Orr

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No, I havn't tried power sanding yet. I have been looking into options for that. If it negates reversing the lathe, that will save a bundle!

Thanks George and Lewis

Leslie

Leslie Gossett wrote: (clip)If it negates reversing the lathe, that will save a bundle! (clip) ^^^^^^^^^^^^ It may not cost a "bundle." DC motors are easily reversed. Three phase motors are easily reversed. Many induction motors are easily reversed. Some induction motors require disassembly and fooling with the wiring, which I do not kinow how to do.

There is a another reason for reversing the rotation besides sanding. I often run my lathe in reverse so I can cut on the inside of a bowl on the side away from me. It is easier to see, and allows the tool to be held in a more comfortable position, without leaning over the lathe.

As far as unscrewing is concerned, if you really cinch down on the chuck threads, it acts like its own jam nut, and will hold quite well. I have never had mine come loose. My lathe allows me to bring the speed up gradually if I think the inertia could unscrew the work.

You could drill and tap for your own setscrews, but, unless your spindle has a groove like One-way's you stand a chance of marring the threads with the end of the setwcrew, unless you insert something soft ahead of the setscrew.

I have found just the opposite to be true. I switch direction with each grit when power sanding. From my experience, this yields a superior surface to just power sanding in one direction.

I do agree with you about power sanding. I generally take it one step further. I don't turn a profile that I cannot power sand!

Peter Teubel Milford, MA

Leslie, As noted in the comments above, the ability to reverse the lathe has many advantages. We build our hollow vessel boring bar systems so that they are completely reversable for just that reason. If you are going to buy a lathe that is both variable speed and reversable in the long run I believe you will be glad you did. The Delta 16" x 42" is an excellant lathe in the $2000 range and there are a host of them at higher prices, topping out at the Oneway 2436 at around $5000. Just make sure you get one that provides for set-screw locking of the faceplate or chuck as the two mentioned above do. Be well, Don

Well I think you guys have convinced me. I was thinking about getting a DC motor and controller for my lathe. Now I see all the merits of doing so. Using a set screw is no problem either. Thanks for all of your input!

Leslie

If you can stand the price difference, go for a variable-speed ac motor and controller. The improved stability and torque at low rpm are a real plus.

Bill

I use a flexible shaft for sanding. The handpiece can be placed on the rest to steady, allowing the lightest touch on the wood. With the lightest touch, there is little heat buildup, and no case-hardening, though I do wet prior to the final sanding just to set up what might have been compressed. It's the compression and case-hardening the reversers are getting out by sanding against the compression.

This

or just go to Lee Valley's site and look directly for 33J73.01, willdo a great job. I use an old washing machine motor and one of those cheapnon-keyed chucks, the whole hanging over the headstock of the lathe. Worksto 320 grit on my setup. Finer, and it's time to stop the lathe and use my400 RPM drill, though most advocates of paper beyond 320 use a lubricant,anyway, and it's possible this would work as well. I simply don't likesawdust crammed into my wood pores. If you like the burnished look, you canalways do it with _clean_ shavings or a piece of Kraft paper from a grocerybag.

Think about it. You're sanding pretty much across the grain all the time. Direction of travel on the piece is not significant.

Extra sanding when you reverse is probably as good as extra sanding in forward or with the lathe off at improving the surface. It's the extra that counts.

grit when power sanding. From my experience, this yields a

further. I don't turn a profile that I cannot power sand!

Granted, the direction isn't, but it's changing the direction from time to time that makes the improvement. I've been known to stop the lathe and hand sand axially, too. I think its because of the lay of the fibers. Perhaps wood has nap and changing the direction cuts the fibers that normally just lay down.

George,

What do you mean by the term "case hardening"?

Jay in NH

Peter Teubel Milford, MA

Dan, I think you hit the nail on the head. I power sand in both directions also and I think it makes a difference. While the grit on the disk is moving perpendicular to the direction of the wood, the wood is still spinning and the fibers are being bent at an angle to the direction of the spin. 45 degrees if the wood and grit are moving at the same speed. Reversing will pick up the grain.

Dan Bollinger wrote: (clip) Granted, the direction isn't, but it's changing the direction from time to time that makes the improvement (clip) ^^^^^^^^^^^^^^ I asked my son's shop teacher about that once, and he said, "Just reverse the sandpaper." It was good for a laugh, but I think he was wrong. Wood is a fibrous material, and the ends of the fibers are laid down like grass in the wind. Reversing gives the sandpaper a chance to do some additional cutting before the fibres are all laid down in the new direction.

I find that another approach to this problem is to apply lacquer sanding sealer to the wood between the final stages of sanding. It penetrates the wood, and "glues" the fibers together and stiffens them. Further sanding then "clips" the fibers off rather than reversing them. To a degree, anyway.

(clip) I asked my son's shop teacher about that once, and he said, "Just reverse

If he was talking about power sanding, as most people do on lathes now, doesn't it make sense to "reverse the sandpaper", in other words turn your power sanding device in reverse rather than the lathe. I use one of the Milwaukee drills for power sanding and usually have the drill in reverse while the lathe is turning forward. If the reversing of the lathe's direction serves to allow one to sand laid over fibers from a different direction, reversing the rotation on the drill should accomplish the same thing. A reversible drill is a lot less expensive solution than retrofitting your lathe with a reversible motor (disregarding any other benefits) also solves any concerns about the chuck unscrewing when lathe is reversed.

Heating the surface causes a set in the fibers. They are over dry, and contract. It's really burnishing. Dull knives on a planer will do the same thing, belt sanders are notorious for it. The next grit of paper has a tendency to slip over the hardened surface, and, of course, as the reversers know, the scratches of the previous grit are highly visible in contrast to the burnished surface.

Heat is the enemy in sanding, which is why a light touch, such as when you support the handle of the shaft on the toolrest and let the work come to the disk, rather than steady the disk on the surface being sanded, cuts down on the friction, and therefore the heat.

Sand on the other side of the disk if you believe this. 3:00 versus 9:00.