scraper angle and Bill Grumbine

Re: scraper angle and Bill Grumbine

Doug Trembath

>I'm not Bill, but the easiest way to true up the tenon on a dried roughout for a hollow vessel is to chuck up a small piece of wood in the chuck, and turn a jam chuck with a tapered profile, sort of like a cone shape, allowing the roughout's opening to be held by fitting over the cone until the edges contact the cone surface. Make the taper short, so it doesn't become a wedge which can split the mouth of the vessel, just enough to make good centering contact. I do this cone thing so various sized openings will fit on the same jam chuck. Then use the tailstock to hold the roughout between centers. It's easy to true up the tenon this way. Reverse it back into the chuck and return and finish sand as much as you can, then after the piece has been trued up and finished, reverse it back between centers with the jam chuck to finish the base and bottom, leaving only a stub on the bottom, which can be carefully sawn off and cleaned up with a chisel or carving tool and sandpaper. I often use a piece of sanding or routing pad between the mouth of the piece and the jam chuck to cushion the piece and provide friction without excessive tailstock pressure. Hope this is clear as mud. Email for additional info if required.

Doug Trembath

Studio in the Woods

Re: scraper angle and Bill Grumbine

DWFII

>Doug,

Thanks for the response. I can see it. I like the idea of the cone. So...

One follow up if I may? What do you do if you want to preserve the tenon--make a foot for a vase? You can't very well bring the tail stock up...or can you?...because that just makes more marks in the tenon which have to be turned away. Maybe this is where a waste block would be appropriate. I just wonder if a dry waste block will reliably adhere to the green rough blank and I wonder if it will distort at all as the rough turned blank dries.

Facinating, isn't it?

DW

In the high desert of central Oregon

Aha!

Ted Owen, Pittsburgh

>A guy with short hair demonstrated that very technique at our last turners' club meeting... : )

Best, Ted

P.S. Great demo, Doug. Thanks for everything.

Re: scraper angle and Bill Grumbine

Bill Grumbine, Kutztown PA

>Hi DW

I see Doug has already answered, and just the same as I would. A stubby cone is important, because just as he says, you can split a piece right in half! If you want some more friction, put a rubber pad of some sort between the two.

As far as saving the tenon for a foot or as part of the turning goes, I have done that on numerous occasions. You need to plan for it a bit, and there are always marks on the bottom which need to be removed one way or another. Depending on your chuck jaws, there are more or less marks, but than that also affects holding power too.

Bill

Re: scraper angle and Bill Grumbine

Bill Howatt

>I have gotten into vacuum chucking and have made some homemade drum vac chucks out of MDF and various sized sewer pipe couplers with some foam glued on the rim. Found that the drums work real well with the tailstock for holding rough-turned bowls to trim tenon (I also sometimes just flop over my Oneway chuck too) and they also work for finishing with the tailstock if I can't use the vacuum for any reason.

If the vacuum is marginal I will do the bottom finishing with the tailstock in place and then trim the tiny little nib left with just the marginal vacuum holding it. You can get down to a pretty small nib if you have a skinny parting tool or use the edge of a skew.

Bill

Re: scraper angle and Bill Grumbine

Doug Trembath

>I can't tell you how many vessels I have had to try to catch as the reduced vacuum and the reduced size of the nubbin combine in failure. I have taken to using the tailstock almost at all times, because when you get into a rhythm, and do things the same each time, I find it's more successful. I am also turning wood that's marginal at best for vacuum chucking, anyway, like heavily spalted Maple, burls, and such. Also too thin, and you can breathe through it.

I leave the nubbin fairly thick, like 3/8" minimum, and trim it off with a saw and a chisel, either straight or wide sweep carving tool. Believe me, I've left blue marks and deep dents from Ol' Blue, my VL-300 Vicmark, on some truly exquisite hollow vessels. I've even saved a couple like that, but more often than not they will split from the impact, or have the finish torn up too badly to save. YMMV

Doug Trembath

Studio in the Woods

Re: scraper angle and Bill Grumbine

Doug Trembath

>DW, that's what turning it between centers means, that you bring up the tailstock, gently squeezing the turning between the jam chuck and the live center. I use a cup center, with a center point on the tailstock, so I can repeatedly index the turning. I start all of my turnings between centers, so I always have a center reference, even if it's warped out of round during the drying cycle. I leave sufficient meat there when I rough them out so that I'll have enough to true it up between centers, then put it back in the chuck, finish turn it, and then go back between centers for the wrap-up. Many of the pieces I do will be in and out of the chuck repeatedly, in combination with between centers, as I add additional pieces of wood. Anyway, Bill's right, use a fairly squat cone, a rubber or other pad between the turning and the jamchuck, bring up the tailstock, and turn the tenon down to the shape and size you desire, leaving a nubbin at the live center end When you're finished sanding the base area and bottom, remove it from the lathe and trim off the nubbin, and finish sand that area again.

Not at all as much work as it seems, folks. I haven't seen Bill's video, but I'd bet he demonstrates this process effectively. How 'bout it, Bill?

Doug Trembath

Studio in the Woods

Chuck marks and tenons, as Bill has said, will have to be removed at least down to fresh wood, or there will probably be bruising of the fibers, and you don't want to have to deal with that.

Re: Oh, man! Don't tell everybody!

Doug Trembath

>