Perfection????

[John Terefenko]

Have a question. I am looking for a sure fire way to make perfect round blanks. I only have a wood lathe so keep this in mind. Looking to chuck up some 2" stock about 8" long (max) I would like to wind up with a perfect round dowel of various sizes. I have round blanks down using the tool rest and skew and finger guiding and the checking with calipers and so forth but I find this time consuming and not always dead accurate.

Does anyone have a method or jig design with cutter to do something like this??? If so do you have photos?? Thanks.

[Bernie Weishapl]

John I just rough them down and then use a skew for final cuts. The only way I can see to get them perfect and the same every time is a duplicator.

[Thom Sturgill]

Wood, by its very nature moves. While its movement is somewhat predictable given the species, grain orientation and moisture content, unlike metal it is not uniform. Thus the difference in metal working lathes and woodworking lathes. To get a high level of consistency you would have to insure that the tool guide is perfectly parallel to the ways and if moved, is replaced EXACTLY in line with the prior position. This is done pretty much automatically on a metal lathe. A duplicator my be a viable solution, but lathe plus duplicator is almost as expensive as a metal lathe and you can turn wood on a metal lathe.

[Michael Stafford]

What Thom said.... Immediately after turning a wooden cylinder might be perfectly round but as soon as there is a change in humidity the wood is going to expand or contract across the grain and the perfectly round cylinder is going to be slightly oval. If the wood is bone dry and you live in bone dry climate it may remain cylindrical longer but the nature of wood is to move with changes in moisture level.

[Norris Randall]

Don't know if this will help but check out this guy's method.
http://www.youtube.com/watch?v=dR9-gdNdZAA

[Thom Sturgill]

Don't know if this will help but check out this guy's method.
http://www.youtube.com/watch?v=dR9-gdNdZAA
Along that line, Lee-Valley sells this:
252397

While Lie-Nielsen sell this:
252398

[Richard Coers]

What's dead accurate? .0005, .001, .002, .005? A duplicator will get you round, but not that smooth. I use a caliper, check that with digital caliper, then 120 grit on a long board to final size and blend. For me, .005 across 8" would be very good. I also tend to loose dimension at the ends, so start oversize with length, then trim latter. To my metalworking buddy, that's like a foot off tolerance. What are you making? How do you get dead accurate/How do you get to Carniege Hall? Practice! Oh, I just read you need a sure fire method. Metal lathe

[Steve Doerr]

You could build a jig that rides along the ways that will hold a router at the center line. Put a bit in the router and turn it on. Slide along the ways at a slow and steady rate as the lathe runs. This could be designed so that you could make consistent round blanks of any diameter and length. You could then also use this to cut coves, grooves, etc vertically on your turnings. HTH
Happy Turning
Steve

[Prashun Patel]

I have the LV jig Tom references. It works great for long dowels. However, it's fixed size: 3/8, 1/2, 3/4.

What's the application?

[John Terefenko]

You could build a jig that rides along the ways that will hold a router at the center line. Put a bit in the router and turn it on. Slide along the ways at a slow and steady rate as the lathe runs. This could be designed so that you could make consistent round blanks of any diameter and length. You could then also use this to cut coves, grooves, etc vertically on your turnings. HTH
Happy Turning
Steve

I have made something along this lines already so I may just try to work something out with this. Just was not sure about running a router in one direction and a lathe in the other. May have to give a try. Thanks all for the replys.

[Ryan Mooney]

I'm had reasonable luck roughing to above size and then using a piece of wood bored to just over the size I want as a reference and shaving with a skew until the reference piece of wood can just slide over the work piece; working from one end to the other in small steps. This isn't anywhere near 0.001 accurate though, more like 0.01 - 0.05 accurate depending on how careful I am and how much (and well) sanding I do afterwards.

Rough turning to ~close~ and then reaming the piece through a dowel plate gets a lot closer for sure (about as close as you can get imho). Its also reasonably fast, I did ~30 pegs and ran the tenons through a dowel plate to clean them up and it only took me maybe 4 hours to turn and cleanup the whole set (and a lot of that is that I'm a painfully slow turner). One trick there is if the piece you're cleaning up on the plate is a stopped tenon turn the the tenon a small amount underside for a few mm right before the shoulder and you won't have to worry as much about having to clean that up afterwards.

I'd be interested to know how the router jig works out if you try it...