Bending stems

[Jim Wilson]

Since we are back, I think I'll pose a question that I have been meaning to ask for a while. How do different people deal with spring back when steam bending things like stems?

I normally just bend to the form made from a tracing of the old stem. Of course, then I have to pull it in because of the spring back. Who else does it this way, and who tries to deal with the spring back on the form itself? If you make the form with an over bend, how do you decide how to change the shape of the form? Do you take the species of wood into account since some spring back much more than others?

That should be enough questions to stir the pot a bit.

Welcome back everyone!

Jim

 

[Fritz Koenig]

Corrected on the form

I took the advice of the Stelmock and Thurlow and corrected on the form. I tapered the bend back. It didn't work out quite right the first time so I tapered it back some more and resteamed it. I am guessing but I think it is tapered to about two inches at the end. I am using ash.

 

[Douglas Ingram]

If you leave the new stem on the form for a week or three, the springback is negligible. So little that you can pull it to the exact position with almost no force. The stems are very stable when you leave them on the forms as long as possible.

 

[Rollin Thurlow]

If I have the time to leave the wood on the form for a decent amount of time I bend to almost the exact shape. If time is short, such as in a restoration class, I plan for some overbending. I find overbending easier to correct than not having put in enough bend.
Hardwoods keep their bend more than softwoods and tight bends retain their shape more than not so tight bends. I have no numbers or ratios to use as a guide, only experience and experimentation to go by.
Many buildes make a mistake in taking their tracing from the old stems using the outside of the curve as the pattern for their new stem. The correct shape for the jig is the INSIDE shape of the old stem. the thickness of the stem may be only 7/8" but it makes a world of difference in the shape of the stem and how it will fit!
Rollin