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Power tool for cutting the wing rib template

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  • Power tool for cutting the wing rib template

    What tool did you use to make the wing rib template out of plywood? I was thinking of using the scroll saw or table mounted router? Any thoughts?


  • #2
    For my master template, I used a jigsaw to get really close to the line, and then a sander to finish it off. After that, I used it as a router template to build all my other templates.

    P.S. - I didn't use plywood for any of my templates. Mine are all MDF, except for the bending form, which is oak plank.
    Christopher Owens
    Bearhawk 4-Place Scratch Built, Plans 991
    Bearhawk Patrol Scratch Built, Plans P313
    Germantown, Wisconsin, USA

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    • #3
      I used 1/2 inch MDF with the thought that the router bearing would be riding on it and the edge of plywood would have voids for the bearing to hit.
      I CAREFULY laid out the Mylar onto the 1/2 inch MDF trying my best not to bias it left or right as I laid it down in the 3M super 90 contact cement.
      Then I compressed it down into the glue by rolling it with a rubber roller as hard as I could. Then I band sawed it out with a fine blade to within about .030 of the outside of Bob's line.
      (as close as I could cut without fear of touching the line) Then I moved to a Rigid oscillating drum/belt sander and very slowly worked it down until I thought I had sanded through
      about half of the blueprint line. Then I painted the edge with minwax wood hardener. Dry 2 days then gave it a very light skim on the belt sander with a fine (220) grit belt. That gave
      it a fine smooth finish. Then I drilled the holes for the pins and bushed them with 3/16 ID chrome molly tubing.
      THEN-- just for yucks --- I made another one as backup. (had bluepring place make me 2 extra mylar copys) Used the original. As usual-- prob more answer than you wanted :-)
      Tim

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      • #4
        Just my 2 cents....MDF is superior to everything except hardwoods....but I get very bad reactions from MDF dust...no matter how hard I try with masks or even sading it outdoors ...it seems to effect me even through my eyes or just landing on my skin....I get light headed and dizzy from contact with it....

        so I changed to 1 inch Baltic birch plywood and I'm happy as a pig in poop now....but as stated above plywood is softer so I put crazy glue on the edges I'll be forming ribs around...

        I also went out and bought a big 12 inch sanding wheel with sturdy adjustable table(harbor freight) to make sure the part is 90% to the face of the wheel....but if I had to do it again I would have done the table saw disk sander modification...where you put the sanding wheel on you table saw ....this I would think would give a very stable platform and finished product ...plus save some money if you already have a table saw...just be careful

        as stated above don't rush the sanding ....wear your glasses if you need them...work carefully to the line.......I recommend using the weakest grit sanding wheel disk you can find....cause if you go past the line....the rib form gods will not be pleased .....

        chris above also has a procedure for using the whole form as his rib former....wish he would talk about that more or,leave a link....looks like a time saver and just plain cool....
        Last edited by way_up_north; 01-03-2019, 12:15 PM.

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        • #5
          Originally posted by way_up_north View Post
          chris above also has a procedure for using the whole form as his rib former....wish he would talk about that more or,leave a link....looks like a time saver and just plain cool....
          I wish I'd documented that step better. I don't think I ever added anything to my project log about building the forms themselves. I probably have some photos I can dig up, though.

          To get a rough idea, though, take a look at posts #1 through #3 to see how I did the various spar fittings:

          https://bearhawkforums.com/forum/bea...645-spar-party

          Then scale up to the rib forms. The technique is the same
          Last edited by Chris In Milwaukee; 01-03-2019, 11:26 AM.
          Christopher Owens
          Bearhawk 4-Place Scratch Built, Plans 991
          Bearhawk Patrol Scratch Built, Plans P313
          Germantown, Wisconsin, USA

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          • cgalutera1
            cgalutera1 commented
            Editing a comment
            Pictures help a lot! Thanks!!

        • #6
          Originally posted by Chris In Milwaukee View Post

          I wish I'd documented that step better. I don't think I ever added anything to my project log about building the forms themselves. I probably have some photos I can dig up, though.

          To get a rough idea, though, take a look at posts #1 through #3 to see how I did the various spar fittings:

          https://bearhawkforums.com/forum/bea...645-spar-party

          Then scale up to the rib forms. The technique is the same
          sorry lots of questions...

          I was curious about you using one former to form all your ribs from nose, center...ect on the same wood form. Was wondering what the procedures you use and if you found it faster/more efficient ? why you chose to do it that way

          the routed out areas for the lightning hole flanges ...curious how that works into the procedure..maybe I missed it in the thread.

          Is there any fast way to router the aileron nose rib to get into those fingers or do you have to drill the hole and cut it out with band saw and file to finish. I cant seem to find a flush bit small enough to get into that small a space.

          with the expedition plane you're working on, its 15% bigger but the gross is seems to be more then 15% larger, how does the math work on that? does the math grow exponentially?
          Attached Files
          Last edited by way_up_north; 01-03-2019, 05:33 PM.

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          • #7
            Here are the tools I made to cut and form the ribs. The rib with the white surface is the forming block I used to shape flanges for the rib. the white surface is the a print of the Mylar drawing glued to hard maple. The tool on the left side is the pattern for cutting the ribs. The rectangular pieces (1/4 plywood) are cover panels to protect the aluminum when I cut the ribs. I used a hand held router to cut all the ribs. All the pieces are aligned with dowel pins. The pieces on the floor are for the ailerons.

            The top picture is for the flanging tools. I made similar tooling for all the ribs. The top of the first picture is a finished nose rib.



            Nose Rib Flangine Tools.jpg

            Rib From Tools.jpg
            Attached Files

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            • #8
              Originally posted by way_up_north View Post

              sorry lots of questions...

              I was curious about you using one former to form all your ribs from nose, center...ect on the same wood form. Was wondering what the procedures you use and if you found it faster/more efficient ? why you chose to do it that way
              One bending form allowed me to do nose, center, aft, flap, aileron, and full-size ribs all on the same unit. That way they was little chance that they'd have any size variation, and that the transitions between the front/center/aft was consistent and smooth.

              Originally posted by way_up_north View Post
              the routed out areas for the lightning hole flanges ...curious how that works into the procedure..maybe I missed it in the thread.
              If you take a look at my Rib Party thread, starting on post #28 (page 2), you'll see that I pressed the flanges in the lightening holes first before doing the edge flanges. The routed areas allow those flanges to fit between the form boards while I hammer out the edge flanges:

              https://bearhawkforums.com/forum/bea...1466#post21466

              Originally posted by way_up_north View Post
              Is there any fast way to router the aileron nose rib to get into those fingers or do you have to drill the hole and cut it out with band saw and file to finish. I cant seem to find a flush bit small enough to get into that small a space.
              Sadly, not that I've found. I only have one trim bit, and it's 1/2" in diameter. I just drilled the holes and cut them out with the band saw as described. It didn't take that long, and it was a cathartic operation.

              Originally posted by way_up_north View Post
              with the expedition plane you're working on, its 15% bigger but the gross is seems to be more then 15% larger, how does the math work on that? does the math grow exponentially?
              Technically, yes. The math for the weight generally increases greater than in its dimension as it gets larger. At this scale, the wing theoretically rates to somewhere around 4000 lbs or so. Destructive testing will show the real numbers. Whatever the wing tests to, I'll design the rest of the plane around that value. If it's a 4000-pound wing, then I'll design a 4000-pound fuselage. The problem is, at some point empty weight can become a problem (there's roughly a cube-rate increase in weight as it's scaled up). It's a fun research project, however, and I'm literally designing it "on the fly". Basic sizing estimates work, but you don't know what you don't know until you've built it. I don't have the expertise that Bob has in this area for guessing how much the structure will weigh, so it's a figure it out as you go sort of thing. So far, the design texts estimate that it's still within reasonable limits.
              Last edited by Chris In Milwaukee; 01-03-2019, 08:43 PM.
              Christopher Owens
              Bearhawk 4-Place Scratch Built, Plans 991
              Bearhawk Patrol Scratch Built, Plans P313
              Germantown, Wisconsin, USA

              Comment


              • #9
                Here is my center rib forming tool. I have all ready hydroformed the edges (this is the center ones which don't have a depressed flange in the lightening hole)
                The hydro press bends to about 60 degrees for the .032 and about 75 degrees for .025. Then I bump it over more with the two dead blow hammers. maybe lightly at the bend line
                with the white plastic one. This form block is 2 layers of 3/4 MDF glued together---- copy-routed from the master rib form using the alignment pins to locate the geometry.

                The smallest copy bit I have found is 1/4 inch. You MAY be able to find one in 1/8 for something like a roto-zip but instead of a bearing it would have a solid cylinder---
                which should work OK. 1/8 might be narrow enough to go into the aerolons finger slots...….

                Tim
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                This gallery has 3 photos.
                Last edited by fairchild; 01-03-2019, 09:16 PM.

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                • #10
                  MDF dust ???? One troubling thing I noticed is that when I cut it on the bandsaw--- the dust smells like bug spray---- I suspect they put some kind of anti-termite chemical
                  in it to discourage bugs----- but what happens when we breathe it ????? No one seems to admit to knowing what I am smelling ……….
                  I have been using my shop vac hooked to the sander and bandsaw--- that seems to greatly minimize the dust in the air..... wonder if I need to use a p95 particle filter ??????
                  Tim

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                  • #11
                    Originally posted by Chris In Milwaukee View Post

                    One bending form allowed me to do nose, center, aft, flap, aileron, and full-size ribs all on the same unit. That way they was little chance that they'd have any size variation, and that the transitions between the front/center/aft was consistent and smooth.



                    If you take a look at my Rib Party thread, starting on post #28 (page 2), you'll see that I pressed the flanges in the lightening holes first before doing the edge flanges. The routed areas allow those flanges to fit between the form boards while I hammer out the edge flanges:

                    https://bearhawkforums.com/forum/bea...1466#post21466



                    Sadly, not that I've found. I only have one trim bit, and it's 1/2" in diameter. I just drilled the holes and cut them out with the band saw as described. It didn't take that long, and it was a cathartic operation.



                    Technically, yes. The math for the weight generally increases greater than in its dimension as it gets larger. At this scale, the wing theoretically rates to somewhere around 4000 lbs or so. Destructive testing will show the real numbers. Whatever the wing tests to, I'll design the rest of the plane around that value. If it's a 4000-pound wing, then I'll design a 4000-pound fuselage. The problem is, at some point empty weight can become a problem (there's roughly a cube-rate increase in weight as it's scaled up). It's a fun research project, however, and I'm literally designing it "on the fly". Basic sizing estimates work, but you don't know what you don't know until you've built it. I don't have the expertise that Bob has in this area for guessing how much the structure will weigh, so it's a figure it out as you go sort of thing. So far, the design texts estimate that it's still within reasonable limits.
                    oh oh ...more questions....;0

                    do you find forming the lightning hole flanges first and the rib edge flanges second makes for a flatter less stressed rib or other reasons? its an interesting way of doing it.

                    on your beater board former you have flutes built into the board that run completely from one side to the other, do you have a procedure to prevent the metal from crimping at the edge when you do the flutes into these grooves? Is it as simple as staying away from the radius edge to get a nice radius in the flute.... it would be a big time saver having one board to do both sides.







                    Last edited by way_up_north; 01-04-2019, 09:47 PM.

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                    • #12
                      [QUOTE=way_up_north;n43111]

                      sorry lots of questions...


                      Is there any fast way to router the aileron nose rib to get into those fingers or do you have to drill the hole and cut it out with band saw and file to finish. I cant seem to find a flush bit small enough to get into that small a space.

                      Check out page 19 of the file attatched to the first post of this thread. https://bearhawkforums.com/forum/too...hawk-jigs-dies big

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                      • #13
                        [QUOTE=Startin22;n43173]
                        Originally posted by way_up_north View Post

                        sorry lots of questions...


                        Is there any fast way to router the aileron nose rib to get into those fingers or do you have to drill the hole and cut it out with band saw and file to finish. I cant seem to find a flush bit small enough to get into that small a space.

                        Check out page 19 of the file attatched to the first post of this thread. https://bearhawkforums.com/forum/too...hawk-jigs-dies big
                        Thank you very much for the tip....I had seen that file months ago when I went through the tips and tricks area but forgot all about it.....

                        so the tip they use is a plunge cut tip....looks kinda like an end mill cutter ....they got good results, just do one at a time

                        i think the only change I'll make is put some candle wax or Boeing lube on the shank of the bit and the template edges of the fingers so the smooth part of the bit glides and does not burn the template..since it has no bearing.

                        the way they made thier hole flange plugs is interesting....need to look at the lee valley catalogue check out that circle making jig

                        also the tip,of writing on the router table the feed direction is gold....

                        thanks again...

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                        • #14
                          I made the master rib template out of 1/2” MDF. That is the ideal material for the master template. Attach the Mylar template to the MDF with a temporary spray contact cement. Then cut out with a jig saw just leaving the line. you then want to sand just up to the line with a table mounted disk sander. This is important to get a 90deg angle on the template. You could use an inexpensive unit from Harbor Freight or a sanding disk on a table saw. I have been a furniture maker for many years and this is also the process we use to make templates. Remember the template will ONLY be used to make the individual templates you use to actually form the individual ribs, etc. Fine wood dust of any type is dangerous to your lungs. MDF dust is particularly fine. Always use a proper dust mask, eye and hearing protection for all of this. It is good to get into that habit early. I wish I had when I started wood working 30 years ago.

                          For the actual forming ribs several materials will work. I used 3/4” MDF with the edges hardened with super glue. You will trace onto the 3/4 material using the master template. Then cut out with jig saw leaving 1/8-1/4”. Attach the pieces together using 1/4” bolts through the jig holes and route on a table top mounted router with a good carbide flush cutting router bit. You do not need to buy a router table. Just make one out of a piece of plywood.

                          now all forming templates will exactly match the master template. If you damage a forming template half way through, just make a new one. It takes just about 10 minutes to make a new forming template.

                          A disk sander and and a good router will be useful for many tasks in your building journey also so they are a good investment.
                          John Snapp (Started build in Denver, CO) Now KAWO -Arlington Washington Bearhawk Patrol - Plans #255 Scratch built wing and Quickbuild Fuselage as of 11/2021. Working on skinning the left wing! -Ribs : DONE -Spars: DONE, Left wing assembly's: DONE., Top skins : DONE YouTube Videos on my building of patrol :https://m.youtube.com/user/n3uw

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                          • #15
                            For the ribs I had two blocks. A lower form block and an upper backer. The backer was slightly undercut around the edges. I did the edge flanges first, fluted them, and then I swapped the two blocks. The backer becomes the form block for the lightning holes. And because it's undercut around the edge the flutes clear it.
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                            This gallery has 2 photos.
                            Mark
                            Scratch building Patrol #275
                            Hood River, OR

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