Primitive Archer
Main Discussion Area => Bows => Topic started by: DC on December 17, 2019, 03:08:10 pm
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I'm thinking I want to taper the belly of my next bow so I get a nice even bend when I do the reflex glue up. I have a cobbled up thickness sander that I could make a sled for but what I need is some brilliant idea for making the first taper to be the master for the sled. I thought of sticking gradually lengthening pieces of masking tape on the master to make the taper but I wondered it anyone had come up with a better/easier way. I could try to free hand it on the bandsaw and then try to true it up on the belt sander but that might be iffy. Any other plans?
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If you are still using a single piece for the belly you're better off by just doing a reverse tiller job. Doing a sled taper won't account for any idiosyncracies within the belly material.
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I plan on leaving it thick enough to tiller. I just thought that rather than have it the same thickness all the way out I might as well get a head start on the taper.
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DC,
For simple 2 lam bows I taper the belly with progressive passes on a jointer like in Dean Torges video. It works pretty well as long as your blades are sharp and you don't get any grain tear out. Also make sure to keep your fingers as far away as possible!
The only other way I can think of making a thickness sled is to buy tapered lams for a glass bow and glue them on a flat board for your taper sled. just remember that the taper of your lam will be the opposite of what the sled looks like.
Hope this helps,
Taylor
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Don't have a jointer. To ornery to buy a lam, I like to do things myself.
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You can make adjustable sled using two boards. Connect one end of boards with hing and You can change the angle with wedge between the boards on the other end.
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Yes you can use drill bits between the parallels to precisely alter the 'gap'. If you decide to go that route.
You are best off buying two tapers from Big Jim's or similar, get an 0.001" and an 0.002" then you can make any taper easily. Trust me this is your best bet because they will be perfect....and whats the point if they aren't perfect :) There are lots of ways to bodge them but I won't recommend any. Do you make your own shop tools? If not why not buy two lams?
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Good idea if wooden bow does not need more taper :).
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Two hinged boards will work,but the need to be good and stiff.
I made a sled from some lengths of OSB glued together (ply would do nicely too) ,marked to the taper and carefully run through the bandsaw.
Del
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Hello Don
I therefore invented an adjustable sled...you can still see a test-lam fixed on it. You can change taper with with the screw in the nut...furthermore I can adjust the height of the belt-sander arm. It's pushed trough under the sander...
If you work a little more precise and accurate tha I did on my prototype, it should be good enough...
I do fix the lam on the sled with double-sided tape.
Cheers
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+1 on the double sided tape :)
Del
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You're on a good track. It does help to pretaper the limb area prior to gluing up a relfexed or recurved bow, plus you could use it to taper lams for trilams and such. I have an adjustable/hinged lam sled made of aluminum. It's the shizznit. I originally made it for grinding glass bow lams, but have used it a lot more for all wooden bows than I ever did for glass bows. Anyway, my point is, even with aluminum, I added two little braces on each side to eliminate any deflection as it went through the thickness sander. Something to keep in mind if you go the 'hinged' route. Hinged sleds are nice because they're made with two flat pieces. You don't have to try to create the perfect taper with masking tape, drill bits, etc, you just hinge two flat pieces and then can adjust to make any taper you will ever want.
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I use bamboo flooring for the sleds and have sleds .001 thru .005 taper there pretty easy to make if you have a thickness sander the .005 -.006 would get you in the ball park you could get more accurate by cutting the lams in half & scarf jointing back together & using the sled but Bayouben has a system for doing full length lams also there is a guy in the netherlands that use the tape sled you described for his BBO's also you can make matching sleds for your band saw saving lam material by cutting the lams taper in before grinding saves grinding time and material with very little waste , scarf jointing with a disc sander and strait edge back together ones your set up you can make a lam from start to finish in under a hour plus if you have that set up you can combine multi thinner lams of different tapers to achieve a over all taper if you like , by pre tapering you save a lot of undo stress on the bow and tiller is a peace of cake its realy internal tillering !
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Thanks guys, I think I can be dangerous now :D
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Will your continplating your dangerious ventures you can also make a sled that will grind in a so called super lam combining taper , power lam and tip wedge all in one lam saving mass and ease of glue up :OK
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Just to make this clear I am not getting into multi lam bows :D :D I'll glue on a backing but that's it. I'm just trying to get the two limbs the same shape before I stick them together.
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wow you guys are making my head hurt,, whew,, :)
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Don here is some pics of the bamboo flooring sleds cheap to make and no double back tape needed some guys use skate board sand paper but I have never found it necessary with wood lams , curved horn lams I use it but I just hold the lam with my fingers tell 1/4 way threw and they stay put by not using any thing between the lam and sled you get a more accurate grind on you lams flipping and rotating every other pass or so & taking off small amounts helps precision too !