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resawing mahogany for back and sides
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Author:  sprouseod [ Wed Nov 18, 2009 10:15 am ]
Post subject:  resawing mahogany for back and sides
I recently found a decent size piece of Honduran mahogany approx. 1'x10'x2" slab cut. I am thinking about trying to resaw it myself. I have a 14" PM with the riser block. my main goal is to experiment with laminate sides w/o using two good sets of EIR. and if some decent set of HM come out so be it

Just curious about
A: is this a plausible idea
B: recommendations for blade, setup etc
C: can anyone direct me to a good video or site that may have more info
D: this is not something I plan on doing regularly should I just take this to a local mill and let them do it?
thanks
richard
Author:  Shane Neifer [ Wed Nov 18, 2009 11:07 am ]
Post subject:  Re: resawing mahogany for back and sides
Hey Richard,
I won't comment much on the applicability of H. Mahog for laminate wood but don't see why it wouldn't work except that it is open pored so thin pieces with a thin viscosity glue (like epoxy) may result is some glue bleeding through the pores.

Back to re-sawing. I recently cut up about 60 sets of Hondo and it cuts very nice! I am using a Hitachi resaw with a 3" stellite tipped band but I have sawn lots on my other band saws. I would use like 1/2" 3tpi band, something of good quality and the fewer the teeth the better. Better quality bands are tougher than cheaper ones but more importantly they are sharpened better with more care for rake angle and chip clearance.

Make yourself a tall fence that you can actually put some pressure against so it does not distort. I faced my fence with UHMW so that it has a high coefficient of friction. Make sure that your fence angle (across the table) is parallel with your blade cutting angle (so that when you view the back of the blade as the wood is running through it the clearance of the blade is the same on both sides of the blade, this will be the result of the set in the teeth).

After every pass I flip the billet end for end, this equalizes any taper in any of the cuts and I think it is just good practice and I do this on both of my re-saws all of the time. Cut slowly, but not too slow. Listen to the saw and you will here when the saw hits its sweet spot for speed. Remember that the limiting factor for re-sawing is typically how well the sawdust clears the kerfs (that is why you want large kerf, low tooth count = more room for sawdust until the blade clears the wood).

Lastly, which should be firstly, is layout your board for all of your cuts before you start to cut it. Typical "sawmills" will have no idea of your needs from this wood for musical instruments. Before I bought me woodmizer I had some local guys that run these saws all day all week (friends of mine) do a couple of things for me, these guys are good but just didn't quite get what my expectations were.

Good luck

Shane
Author:  Tim L [ Wed Nov 18, 2009 11:39 am ]
Post subject:  Re: resawing mahogany for back and sides
I know this is different than what you have planned, but that sounds perfect for laminated necks. Easier to process too.

I have resawn billets in Mahogany, Walnut, Koa, Spruce and Cedar on my DoAll vertical bandsaw. I use a 1" blade with 2-3 teeth per " and my fence is little more than a 3" x 4" chunk of aluminum that is clamped to the table. Most important things for me are making sure the billet is squared up and that the fence is set true so the blade doesn't bind. I'm sure Shane has cut alot more than me, and on a dedicated machine. Going slow and finding that sweet spot really is the key. Of course a sharp blade and a bit of an air blast on the exit doesn't hurt and helps to keep the blade clean and cool. The guy who cuts the wood for Allied couldn't believe how straight my cuts were on a 9" wide billet of Koa. I should add that I use that saw simply because that is what I have in my shop and I cut a lot more than wood.

Tim
Author:  JohnAbercrombie [ Wed Nov 18, 2009 1:14 pm ]
Post subject:  Re: resawing mahogany for back and sides
Richard-
Thanks for asking this question- I've 'filed away' some of that expert opinion from the posts above.

A couple of points-
Sawing sides (for double side laminations) should not be too difficult; it will be trickier to saw the (potential) back sets.

Don't be too 'miserly' about trying to get the maximum yield from your board- when I started sawing, I found that a bit of a 'wobble' in the cut could make an entire back piece too thin - best to leave a bit of leeway for mistakes, IMO. (different tactic if you are sawing v. valuable species, of course).

Buy a 2x10 from the lumberyard/HomeDepot and practice on it- something reasonably dry and pitch-free.

As Shane mentioned, setting the 'drift' (fence angle) set properly is important- you may need to play around with your fence to make the angle adjustable. Especially on a smaller (less rigid) saw, all the adjustments interact (the frame does bend) so you need to get the blade tension and tracking set up before you set the fence angle. My experience with the 14" saw was that you can't necessarily count on the 'setup' staying good for your entire sawing session- if you start to have problems with blade binding/wandering, etc, you should probably stop and re-check the fence angle with a cut in scrap. Again, some practicing with cheap wood will help.

I agree with Tim that you have some perfect stock for laminated necks there, so you might think about saving a chunk for that purpose. If your plank is flat-sawn, you'll get nice quartered lam necks out of it.

Cheers
John
Author:  John Hale [ Wed Nov 18, 2009 4:04 pm ]
Post subject:  Re: resawing mahogany for back and sides
Sorry to take this a little off topic, but what sort of horse power motor do you need to re-saw say an 8" back?
Author:  TonyKarol [ Wed Nov 18, 2009 4:13 pm ]
Post subject:  Re: resawing mahogany for back and sides
It can be done on 3/4 ... I have cut quite a few sets on my 3/4 Delta 14 with riser .. I have cut as tall as 11 inch padauk, 48 long ...
Author:  Shane Neifer [ Wed Nov 18, 2009 4:37 pm ]
Post subject:  Re: resawing mahogany for back and sides
John Hale wrote:
Sorry to take this a little off topic, but what sort of horse power motor do you need to re-saw say an 8" back?


Yup, Tony is correct! HP is not as important as blade selection, blade sharpness and feed rate. I only have 5hp for my big re-saw (the mill is 25hp though) and just change bands often, just as soon as they start to get dull. It keeps the cuts clean and the bands are easier to re-sharpen as well.

Shane
Author:  bluescreek [ Thu Nov 19, 2009 7:39 am ]
Post subject:  Re: resawing mahogany for back and sides
one note you need to know , is the blade. You need a very coarse tooth , Too fine a tooth and you will have a difficult time cutting . Heat build up is not a good thing , the blade will not track well. I use a 1 2/3 tooth per inch. Also get as wide a blade as you can run. Feed rate will need to match tooth design.
As you feed you will feel when the wood seems to cut the best. It can be done , you need to be aware of what will and what won't work. Also be sure to square up the blank as best you can.
Author:  unkabob [ Thu Nov 19, 2009 10:24 am ]
Post subject:  Re: resawing mahogany for back and sides
Check out the literature on the Suffolk Machinery web site. They have a good basic primer on bandsaws.
Author:  Markus Schmid [ Thu Nov 19, 2009 11:36 am ]
Post subject:  Re: resawing mahogany for back and sides
When resawing, instead of using the fence as a fence I use it as a rail:

Image
Click on the picture to see more pictures from the gallery of this set-up

The cut will be much more precise with the "rail solution", and operation will be saver too (no hands near the blade, and you won't have to concentrate on pushing the working piece against the fence).

The working piece in the picture is screwed to the guide from behind. When I resaw a square angled block of wood I "spot-glue" it with titebond to a vertical guide, with a sheet of paper between guide and the wood in order to separate it without any problems after the job is done.
My saw is equipped with a 1.5 HP tri-phase motor (saw is an "Inca Expert 500", "Inca 710" in US). For me, with this band saw HP is not the limiting factor, it's the sawblade.

It works like a charm, with an ordinary 20 mm blade (ca. 3/4"), cutting height of 200 mm (maximum for that saw is 203 mm), I can cut 3mm thin veneer completely even.
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