I am thinking about building a batch of prewar stringers from doug fir

[astjp2]

Building a batch of prewar stringers from doug fir. They would be vertical grain, clear. would anyone be interested in any if I decide to do this? I would probably make them 14' long, which is the top 2 were on my '41. They will not be exactly like the originals but pretty close and much closer than what they sell at spruce. If anyone would be interested, I would ship them freight to a local terminal for cost... I am just feeling the market out on this. Interested, post a reply or PM me. I have no idea about cost, the raw boards for 1 airplane are over $250...plus some labor for me to build into stringers...and shipping. Tim

[Hank Jarrett]

Re: I am thinking about building a batch of prewar stringers from doug fir

I would agree that Doug Fir is a better choice than Stitca Spruce. The fir is just a tad heavier, but stronger and has better dimensional stability (less wave between supports when on the fuselage). If you want, I did a cut plan for the ones I was going to make to minimize waste and provide as much support for forming the vert leg as possible. Might be able to squeeze an extra stringer from each board.

The biggest problem I found when planning to do mine was the cost of shipping was ridiculous! If you have a router and table saw you can make them, but I would practice on some cheap pine 2x4 first to be sure the set up is right before blasting away into that solid gold wood!

Hank

[astjp2]

Re: I am thinking about building a batch of prewar stringers from doug fir

I plane the 2x6 to thickness (height) and then rip the stringers to to width, router the tops and then use the table saw to remove material to make it a "T"

[3Dreaming]

Re: I am thinking about building a batch of prewar stringers from doug fir

There was a fellow on the Taylorcraft Facebook group who was going to have some made a while back.

[Hank Jarrett]

Re: I am thinking about building a batch of prewar stringers from doug fir

I plane the 2x6 to thickness (height) and then rip the stringers to to width, router the tops and then use the table saw to remove material to make it a "T"

I looked at that too, but found a more efficient cut plan. You start by ripping a blank TWO stringers high (1/2" thick and 2 1/2" wide), then rout all four corners (I would actually rout one side before ripping to 2 1/2", then rout the other edges), then rip out both sides to make an H section and lastly cut the H into two Ts. You end up with better support for the wood when making the cuts so it doesn't try to twist while being cut.

Hank

Finally got to use that process engineering class!

[Hank Jarrett]

Re: I am thinking about building a batch of prewar stringers from doug fir

Looks like I am moving forward a bit faster than I thought I would and have started my stringers. I have one estimate from a cabinet shop and will be getting one from a mill work shop along with the wood order on Monday. I will make a decision then on if I want to cut mine myself or have it professionally done.
While digging through all my papers i came across a factory drawing of the wood stringers and the drawing says they were made from pine! I took some of my material to specialty lumber mill works and the cabinet maker and both confirmed that the wood was in fact pine (although they said it was VERY good quality pine!) The grain was VERY straight and tight and it was very good quality wood. NOT the kind of stuff you see now days. The specialty wood shop (they supply wood for local boat builders and even had some VERY interesting pieces there that are use for propeller shaft bushings for Nuke Subs!) is going to see which choices of woods would be close to the strength and stiffness of the original and make sure to exceed that. I should know on Monday and will share info then as well as my cut plan that includes the factory profile.

Hank

[Hank Jarrett]

Re: I am thinking about building a batch of prewar stringers from doug fir

I have been contacted by Max Wenglarz from San Pierre IN on the Face Book group. He is making wood stringers (the mushroom cross section types) from Poplar and will be making extras. As usual the shipping cost is the killer so if you are anywhere near him now is your chance to get on the wagon for new stringers. The stringers are generally not that expensive but shipping long pieces is a killer! I think we have someone with the profile on the west coast, the mid-Atlantic coast (me in SE Virginia) and now in Indiana. Anyone else? You can contact Max through FB with a search on his name (Maxwell Wenglarz). Looks like he is the only one. If anyone is looking for me on FB I am NOT the one who builds BBQs or the Dr. who does infectious diseases! Who would have thought that many people were named Hank Jarrett?

Hank (the one with the rockets behind him and lots of Irish Setter photos)

Just checked and there are now 13 people named Hank Jarrett on FB!!!! And I don't know ANY of them!

[kauaicuda]

Re: I am thinking about building a batch of prewar stringers from doug fir

I have a pertinent question. I stripped the stringers off my L2. Being a "T" section, when the stringers are bent over a little where the fuselage curves would be, the thin section of the stringer buckled and contorted because it couldnt compress to make that curve. I had given some thought to making some relief cuts or thinning down that area of the cross section to enable it to make that bend. Anyone else doing the same?

[3Dreaming]

Re: I am thinking about building a batch of prewar stringers from doug fir

I have a pertinent question. I stripped the stringers off my L2. Being a "T" section, when the stringers are bent over a little where the fuselage curves would be, the thin section of the stringer buckled and contorted because it couldnt compress to make that curve. I had given some thought to making some relief cuts or thinning down that area of the cross section to enable it to make that bend. Anyone else doing the same?

You could do that to get it to make the bend, then after it is in place cap it with a couple thin pieces of plywood to regain the strength.

[Hank Jarrett]

Re: I am thinking about building a batch of prewar stringers from doug fir

Gentle application of heat (GENTLE!!) while using a rubber band to pull them can get them to cooperate. The problem is the bottom edge of the "T" is going into compression and wood does NOT like to compress. It would rather just buckle out to one side. Cutting slots for the bend is not a great idea since it REALLY destroys the bending strength of the stringer. If the problem is REALLY bad you can steam the stringer where you want it to bend and then lock it in place while it drys and cools. You will need to clamp some angle to the "T" section so it stays straight while drying.

Hank