Erma conversion kit- long box reproduction

[sheepherder]

Don -

One thing I have noticed on that soft pine box for my Nambu that I made, is that after milling/routering out the slots, the box halves will warp. The board I selected was nice & flat and stored inside here for a week or so until I milled it. My board and box was stored in my house, in a controlled climate area. I'm theorizing that the loss of some wood, from one side of the board only [the slots], caused an unbalance that allowed the boards to warp.

It took several weeks, maybe months, to warp. I didn't check it closely and only noticed it when I was getting ready to put my 'artillery Nambu' on GB.

[Olle]

Wood is funny that way... You start out with a perfectly straight piece, mill, drill etc and all of a sudden it moves on you. Actually, I have seen the same thing happen with steel, especially when you mill it really thin. There is always some stress and tension inside the material, and when this is released you'll end up with a warped piece.

One way to get around that is to work with an oversized blank, and true it up once all the cuts are made. There's still no guarantee that it won't keep moving, but a good coat of oil usually seems to stabilize it. Denser wood species don't move as much, but pine, poplar and such can really act up.

Wonder how they did it back in the good ol' days?

[sheepherder]

Originally Posted by Olle

One way to get around that is to work with an oversized blank, and true it up once all the cuts are made.

+ 1

My thought was to wait a couple weeks/months, and then plane it flat. My pine box was just a 'feasibility study' to see if it was difficult/time consuming/boring. If it was something that would ultimately interest me, I would step up to maple or walnut.

It's good that Don is making these!

[DonVoigt]

Originally Posted by sheepherder

+ 1

My thought was to wait a couple weeks/months, and then plane it flat. My pine box was just a 'feasibility study' to see if it was difficult/time consuming/boring. If it was something that would ultimately interest me, I would step up to maple or walnut.

It's good that Don is making these!

Actually the pine is fine, no change or warping.
I "fixed" several small boxes last year that had warped, had to sand them flat, then deepen the cut outs.

Ollie is right about the stress, happens with metal too. That is why it has to be annealed and equalized for some applications.

The wood is not that big a deal - it can be "fixed".