mounting green wood for end grain hollowing

[Chris A Lawrence]

Turning on centers, the (Steb or 4-point) center to eventually start spinning a hole in the wet green end grain.

Steb centers are not good for this situation they are designed as a safety center to prevent bad catches. I will echo using a bigger 4 point center if you are using the stock one that came with the lathe. I use the Axminster jumbo drive center and have been able to rough turn 12+ inch diameter logs with out issues.

[Steve Schlumpf]

Stan, I use Jerry Marcantel's drive center on everything I rough out but basically all you are doing is using a jam chuck when spindle turning. If you have everything tight when roughing and it still breaks loose, makes me wonder if you are getting bad catches? Being spindle turning, did you raise the height of your tool rest so that you are cutting slightly above center? Other than that, only thing I can think of is amount of pressure you are applying is either too light to retain the work or so tight that it wants to split the wood. Any chance you can share some photos of your setup? That would help direct everyone's suggestions.

[Don Stephan]

Stan: Having just read your Sunday morning post, could you gently turn between centers enough to make a tenon at each end, then hold each end in turn in a four jaw chuck while you continue roughing out to a cylinder the half of the blank at the tailstock end? Given the experience, as has been suggested more than once I would use the tailstock while roughing out tghe cylinder, even with the four jaw chuck.

[Edward Weingarden]

Your description of your use of the face plate sounds like you are mounting it on the rough blank. If that is the case, there are a few issues to be aware of. The face plate needs to be mounted on a flat surface with a slight concave shape to it. That will ensure that the face plate has complete contact with the wood around the entire circumference of it. The next issue is that with a face plate mounted on a rough blank, you can't balance the blank prior to starting the roughing phase. Spinning a log that is out balance will put addition stress on the face plate/screws. The method I use is as follows:

I mount the blank between centers with a spur drive and live center (as others have mentioned), and balance the blank prior to turning. Once the blank has been turned into a cylinder I square the ends. Since I mount the face plate on what is currently the tail stock end, I make sure there is a slight concavity on that surface. Before removing the cylinder from the lathe, I make pencil marks on the end which will have the face plate mounted on it. I make the pencil marks as the lathe is spinning so that I get a number of circles, each with a slightly larger diameter than the preceding one. I use the circles to help center the face plate. I pre-drill the mounting holes so that the screws are not separating the end grain, but allow the threads to bite into the wood. I have also found that if I didn't pre-drill the mounting holes, it could be very difficult to get the screws out. The face plates I use are 1/4" in thickness; the screws I use are 1 1/4" - 1 1/2" long (depending on the size of the blank). Thus, I have at least 1" of screw in the wood for a smaller blank, and 1 1/4" for a larger blank. My face plates have at least 6 mounting holes (more for a larger plate) and a screw goes in each one of them. When the cylinder is remounted using the face plate and tail stock support, it will run slightly out of true until you make one or two passes to true-it up again. I have never had a blank separate from a face plate using this method.

With all that said, I also use a chuck to mount my hollow forms. I add a steady rest with the set-up if the hollow form is about 8" or deeper. Hope that helps.

[Stan Calow]

Edward, yes I was mounting rough blanks to a faceplate (on a flat end-grain face) with a live center in the tailstock. Just to get the outside rounded. With a tenon, I would go to put a four-jaw chuck if I get that far. I've done many small cross-grain turnings with no issue. Roger, I was under the impression that with a center like the one you show (a single point) you were likely to split a end grain mount since you're pushing into the grain. So I tried using a spur center or a cup center in the tailstock as well.

Next time I'll be trying this, I'll take some photos, but I got a good idea of how to proceed. And yes it never hurts to check the sharpness. Thanks everyone.

[roger wiegand]

That was just a picture I found on the interweb, in use the point is adjusted so it sticks out only 1/16-1/8"-- it's just there for centering on a specific spot. You don't need to use it at all. The ring around it is what does the work.

Edward, yes I was mounting rough blanks to a faceplate (on a flat end-grain face) with a live center in the tailstock. Just to get the outside rounded. With a tenon, I would go to put a four-jaw chuck if I get that far. I've done many small cross-grain turnings with no issue. Roger, I was under the impression that with a center like the one you show (a single point) you were likely to split a end grain mount since you're pushing into the grain. So I tried using a spur center or a cup center in the tailstock as well.

Next time I'll be trying this, I'll take some photos, but I got a good idea of how to proceed. And yes it never hurts to check the sharpness. Thanks everyone.

[Reed Gray]

Well, Lyle Jamieson likes bolts into end grain for his pieces. He uses over sized ones and goes in pretty deep. 1 inch screws won't work. If you use that method, I would suggest 'toe' nailing which means instead of going straight in parallel to the grain, you go in at an angle. It can be made to work. Oh, the part on the face plate needs to be dead flat. Other than that, like every one else does, between centers, turn a tenon, use a big chuck, and for big pieces, use a steady rest.

robo hippy

[Randy Heinemann]

Thanks everyone for input. I always do the roughing between centers, but have had trouble getting live centers to maintain a grip in green wood, thats why I was trying faceplates. I am only doing relatively small turnings on a midi lathe, so can go to a 4-jaw chuck when I get a tenon, just can't get past the roughing stage.

I have begun turning smaller hollow forms on my Nova Comet II; also a midi lathe. The lathe has sufficient power so no problem there. However, I noticed that the size tenon which the chuck allows isn't as large as a full-size lathe. This seems to make it more likely that the chuck will let go when hollowing given the amount of force involved with end-grain hollowing. I do tighten the chuck via both points on the chuck and usually do it at least twice in each. Then I give each a little extra turn periodically as I go through the hollowing process. The piece still ends up coming loose at least a couple of times during the hollowing process. It doesn't come off the lathe, but does loosen up so that I need to remount and retighten.

I think hollowing on a full-size lathe with a larger chuck would eliminate most of the problems I'm having. For now, though, I'm not in the market to upgrade. I suppose I could purchase a different chuck as there are likely others available that would fit and would allow a larger tenon.

I would be the first to admit that I'm new to hollowing as I've turned mostly bowls and this may become less of a problem as I develop my technique. Right now, my technique is a little rough and the results are also.

[Mike Nathal]

I have experienced the spur drive drilling into end grain problem. Never use a Steb center for this. A big reason for this is that the wood is so wet that it is moving too much and you need to continually tighten the tail stock to prevent the drilling. The drive that Roger W. referred to is called a safety center, it may well work, I never tried it on green wood. Continuously tightening the tail stock is the key with the safety drive also. Sometimes you can remove the blank, and clean up the hole you have drilled with a chisel to make it flat again. Sharpening the spurs also helps. As Don suggests, another good way to go is to get a tenon formed right away on the tail stock end, prior to truing up the rest of the blank. Then, if you start to get the spur drive drilling in, you can switch to the chuck. (Always with the tailstock)

[John King]

1-1/4" #12 pan head sheet metal screws with tailstock support while balancing and shaping exterior of piece. - John

[Stan Calow]

Lots of good guidance here. Thanks all. Its one of my long time complaints about guidebooks and videos leaving out a lot of the details or assume too much.

[robert baccus]

To reverse the piece use a glueblock and thick CA glue--it holds very well on wet wood.

[John K Jordan]

To reverse the piece use a glueblock and thick CA glue--it holds very well on wet wood.

Does this also hold well to end grain as the OP is using? I haven't tried that. I assume the end first needs to be flattened before gluing the waste block which might complicate the balancing step.

I have soaked soft wet end grain with fine CA to harden the wood give the drive center a little better bite.

[robert baccus]

Sure---sticks to wet or dry endgrain. used it for dozens of log section vase blanks to 125 #'s. Outside and hollowing (using a stabilizer wheel) and finishing as well. Use plenty of glue and a flat surface yeah. Screws and wood glues are horrible on wet endgrain---dents in my shop ceiling to remind me of the learning curve.