Author Topic: Improved Lamination Thicknesser/Taper Jig  (Read 5486 times)

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Offline willie

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Re: Improved Lamination Thicknesser/Taper Jig
« Reply #15 on: September 20, 2017, 12:05:13 pm »
Del,

do all three lams get tapered?

Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
Re: Improved Lamination Thicknesser/Taper Jig
« Reply #16 on: September 20, 2017, 12:33:44 pm »
Del,

do all three lams get tapered?
Yeah, I'll taper the boo by eye, and use the jig to taper the core and Yew billets for the belly, mind the final tillering will be done by hand/eye.
I don't like the look of parallel cores which then leave the belly very thin at the tip... just my thing.
I'll aim for my somewhere near usual 2mm every 6" taper, which then allows the tips to be tapered some more for final tiller.
The limbs will be tapered billets with a continuous Boo back. I won't try for an accurate match of the billets, as the tillering will be done on the finished bow.
I never aim to do it accurately by numbers, just to get it close, well hopefully a bit over weight so I can bring it in to exactly what I want.
Del
« Last Edit: September 20, 2017, 12:51:44 pm by Del the cat »
Health warning, these posts may contain traces of nut.

Offline Hamish

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Re: Improved Lamination Thicknesser/Taper Jig
« Reply #17 on: September 20, 2017, 07:04:56 pm »
Okay Del, I get it now. Nice idea, especially if you need to work difficult wood like purpleheart, that stuff will blunt a carbon steel handplane blade in no time. HSS on an electric planer is good for abrasive tropicals.
I have toyed with an idea, but have never taken it further than a concept sketch. It relies on an electric handplaner with frictonless adhesive on either edge of the sole to act as runners, and to stop the plane from biting into the form. The plane moves over the form fixed lamination, rather than a lamination being feed into a fixed planer. I believe it is a method used by bambo fly rod makers to rough out tapers, prior to finishing up with a regular handplane.
 Food for thought for some guys who have more time than me for bows at the moment.

Offline Morgan

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Re: Improved Lamination Thicknesser/Taper Jig
« Reply #18 on: September 20, 2017, 10:47:34 pm »
I like that a lot! I added it to my list of things to do in my non-existent free time.

Offline willie

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Re: Improved Lamination Thicknesser/Taper Jig
« Reply #19 on: September 20, 2017, 11:16:00 pm »
Quote
It relies on an electric handplaner with frictonless adhesive on either edge of the sole to act as runners, and to stop the plane from biting into the form. The plane moves over the form fixed lamination, rather than a lamination being feed into a fixed planer.
Hamish,
can you link to or post a pic of that method? I am having trouble visualizing the form.

Offline Hamish

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Re: Improved Lamination Thicknesser/Taper Jig
« Reply #20 on: September 22, 2017, 05:36:01 am »
Willie, Imagine a plank of hardwood planed smooth, or it could be multiple thicknesses of hardwood ply glued together, which would be more stable. Dimensions 2"(3" would be even better, allows for wider laminations and gives more bearing surface so the plane wont tip) x4" tall as long or a little longer than your intended bow. On the top edge saw with a dado head or rout a groove wide enough for the lamination. Depth of the groove is dependent on what type of lamination you are cutting.
If you wanted a form for a belly slat you could make the groove 3/4" or 7/8" deep. If you wanted to do a core lam it could be 3/16"-1/4" deep.

Mark out the handle/ dip area  on the top of the form. From the ends of the board, up from the groove mark up 3/8" if you want to do a belly slat. Connect a line from this point back to the end of the handle area. Repeat for the other end of the form if it is for a full length stave. Saw off this waste, and you have your form. Run a strip of frictionless tape down the each side on the sole of your electric plane, trim the excess from over the mouth so depth of cut can still be set.
 Place your belly slat blank in the groove. It could be fixed to the bottom of the groove with double sided tape , or held in place by screws on side, through the walls of form. Just the tip of screw would bite so the slat insn't comprimised.
Set the plane for a fine cut, no deeper than the thickness of the frictionless tape, so the planer won't cut into the form.
Run the plane on the slat as many times as necessary until the taped part of the sole bottoms out on the form.
Hey presto you should now have a belly slat with a flat section as long as the handle, or fade area, 7/8"deep tapering to 3/8".

If you wanted a form for a core lam, you could use 3/16" or 1/4"deep for the groove, tapering to 1/16" or 1/8".
 My method gets around you needing to add a powerlam under the backing lam, like you often need to do if you use thickness sanded taper laminations. You can still glue on a handle riser if you are making a deep narrow handle, it won't pop off because the flat area gives you enough thickness so the dips won't flex.



 My proposed form isn't very adjustable but minor variations could be achieved by placing a thin parallel lamination of sawn or planed wood on the base of the groove before placing the blank on top.