Shopsmith Forums

I am going to turn a gavel handle about 12" long by about 1 1/4" max diameter.

I want to glue FOUR different wood varieties longitudinally(each will be a quarter segment of the turning).

The species are african blackwood, black walnut, aspen, and red oak segmented it that order.

I want to orient the grain to display the more unique grain features on the outer surface.

My questions are:

Am I likely to get expansion splitting due to grain expansion in this small item. It seems that when I face the desired portion toward the outside, I am also forcing the grain(s) to expand around the handle, not in/out. Since I expect the different species to expand differently, I be concerned.

Is there a 'better' direction to turn this(the different species will react differently under the chisel as they switch from one to the other). i.e. is the sequence above better or worse than flipping the workpiece end for end and thus reversing the sequence?

I am making this for a friend who will really really appreciate it and I do not want to screw it up! The raw materials are scarce and I do want to succeed in one attempt! There will be many opportunities for that after I begin!:eek:

TIA

Wow!! Tough question. I think that the diameter of the turning would be small enough that wood movement wil not be a problem. However I don't know much about the movement of the african blackwood. As long as you put long grain to long grain movement should be minimal. Use a good glue such as Titebond II and proper clamping pressure. I have done laminated turnings but not with that many different varieties. Take very shallow cuts during the turning process to minimize the stress on the glue joints. Did you try any woodturning websites like American Association of Woodturners for advice?
They may be able to help.
Bill V

wa2crk wrote:Wow!! Tough question. I think that the diameter of the turning would be small enough that wood movement wil not be a problem. However I don't know much about the movement of the african blackwood. As long as you put long grain to long grain movement should be minimal. Use a good glue such as Titebond II and proper clamping pressure. I have done laminated turnings but not with that many different varieties. Take very shallow cuts during the turning process to minimize the stress on the glue joints. Did you try any woodturning websites like American Association of Woodturners for advice?
They may be able to help.
Bill V

But That IS the 'issue'! That can be done with 'flat' boards to boards like a table top.

Unfortunately(?) the grain features I want to show seem to be in the area between the rings. With this 'edge facing the outside, the expansion will be around the handle. Think of the rings running from the outer surface towards the center.(viewing from the ends on the handle). I believe this will maximize the tendency for the expansion to push the 4 segments away from each other. This force will methinks be higher in the center than at the outer surface, but there will be more 'rings pushing' near the outside. Bottom line is, will there be sufficient difference in/out to cause separation???

I'm pretty much with Bill. If the wood is dry, as I assume it is, then small pieces like these shouldn't be able to generate much force. Remember you're not even talking about the amount these pieces will expand, just the difference in those amounts between species.

Paul M

shipwright wrote:I'm pretty much with Bill. If the wood is dry, as I assume it is, then small pieces like these shouldn't be able to generate much force. Remember you're not even talking about the amount these pieces will expand, just the difference in those amounts between species.

Paul M

I was thinking along those lines but was not sure if it was of the wishful type.

I need to pick a glue. I be thinking either titebond II or thin CA. Thin as in 'runny', not this gel crap.

Any opinions?

Max strength = Epoxy. Drawback is that you can't clamp epoxy really hard or you'll drive all the glue out of the joint... a bad thing with epoxy. This sometimes leaves you with a tiny bit larger glueline than you wanted. Tightbond II should work fine.

Paul M

shipwright wrote:Max strength = Epoxy. Drawback is that you can't clamp epoxy really hard or you'll drive all the glue out of the joint... a bad thing with epoxy. This sometimes leaves you with a tiny bit larger glueline than you wanted. Tightbond II should work fine.

Paul M

Titebond II it shall be, I will save the ca for when it 'splits'.

JPG40504 wrote:I was thinking along those lines but was not sure if it was of the wishful type.

I need to pick a glue. I be thinking either titebond II or thin CA. Thin as in 'runny', not this gel crap.

Any opinions?

I have some of that thin, runny CA that I tried to use a couple days ago. It must have a shelf life or is sensitive to heat. It no longer sticks to anything except my fingers. I used it in the application that I originally bought it for and the two pieces never did bond. It worked as advertised when fresh.

Good CA works GOOD.

dusty wrote:I have some of that thin, runny CA that I tried to use a couple days ago. It must have a shelf life or is sensitive to heat. It no longer sticks to anything except my fingers. I used it in the application that I originally bought it for and the two pieces never did bond. It worked as advertised when fresh.

Good CA works GOOD.

I keep mine in the refrigerator. That is how we kept it 50 yrs ago when it was called Eastman 910. I do not know if keeping it cool prevents degradation, but it sure helps premature bonding. It does respond to heat(like that in yer fingers etc.) by setting more quickly. Perhaps ambient temp was counter productive by setting it before you got the 'parts' aligned. I really have missed it since the 'gel' variety appeared. I think the gel was introduced since too many folks were sticking there pinkies together and to other objects. Once it 'sets' it will not 'stick' (even to itself) very well.

Its principle good attribute is that a very thin layer provides extremely good bonding. Too thick a layer and it doesn't work as well. Hence my negative opinion of the gel variety. Add the very quick 'setting' to the good attribute list.

Try chilling b4 use next time!

Seems to me you have the right idea concerning grain orientation. You have designed the largest possible wood movement to be from the center to the outside of your gavel.

First let me say the 1 1/2" diameter should not offer enough space to cause significant wood movement. Also, the largest amount of movement will be radial, from the center outward. next comes a lessor amount in a tangential direction. I really don't know much about the expansion of the African wood, but the other three should be pretty compatible, if all species are arranged with the same (or similar) grain flow. (When one expands they all will expand similarly)

Don't over think it! Just do it!
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BTW - I agree with Titebond for the reason it will allow a little creep if there is a difference in wood movement.

Just thinking the wood movement of red oak (being one of the highest) is 8% tangentially. This is roughly twice the movement radially. (in your piece the tangentially oriented grain will be radially situated and the radial movement of the wood will be around the outside circumference (tangentially)

That 8% movement is it's extreme - between fiber saturation point and bone dry. The finished gavel will probably only be subject to 70% relative humidity to 20% - and the wood only from 6% to 10% moisture content.

So a little very simplified math shows that from fiber saturation to bone dry 8% of 3/4" = .0600". The actual radial movement of your gavel will be only a very small amount of that (.06") figure. You can figure the edge movement of you gavel will be only half of that smaller amount. Nothing to worry about!