(Conical) Thickness Sanding, a la Session #14

nuhobby · Post by **nuhobby** » Wed Jul 23, 2008 1:47 am

Hi All,

A few days ago I thickness-sanded some nice crotch walnut that I had resawn. I used a modified (lazy) version of the conical-sanding jig that Nick showed in Sawdust Session #14.

I'm really pleased with the results. However I hope there is some improvement I can make on dust-collection; the pickup I had running near the disk probably only got 20% of the dust.

Questions:

- Has anyone else done this type of sanding, and what can you say about dust-collection?

- Mostly by laziness I stayed with the 150-grit that was already on my disc, so it's really smooth wood. I wonder -- in general -- would a more coarse-grit paper change the dust-creation much? (Such as less fine cloud and more "settling" dust perhaps?)

- I would like to hear about what anyone else is doing to smooth up bandsawn faces on nice figured woods. Your favorite methods of facing and/or thicknessing such pieces. Anyone use either a shop-built thicknesser or a Sand Flee or other on this type of work?

Thanks,

charlese · Post by **charlese** » Wed Jul 23, 2008 2:39 am

Hi Chris! Sorry, haven't used the conical disk sander that way. As for favorite methods of thicknessing, my thickness planer has done an admirable job of thicknessing even wood with some wild grain and hard knots. (I don't usually work with figured wood however.) So far I trust it until getting to a thickness of less than 1/4". At 1/8" I've suffered the loss of the trailing end of wilder grained boards.

Before the planer, I used a hand held belt sander with the appropriate pencil marks. Sanding until the marks disappear - marking again - sanding again - etc. It's time consuming, but works.

Since you have used the conical sanding disk with success, I suggest you stick with that method. The dust situation might be helped by attaching/hanging all three vacuum hoses instead of one.

Good luck!

cowboyplus · Post by **cowboyplus** » Wed Jul 23, 2008 9:11 am

Use the lower saw guard. Max wide opening at the front and as narrow as possible at the hose end. Rotate clockwise as much as possible with the hose against the rail. Captures nearly all dust.

kellycat · Post by **kellycat** » Wed Jul 23, 2008 11:57 am

Does anyone out there have better pictures of the Thicknessing Jig that is used in his video? I downloaded the plans but can't quite see how to attach the opposite end from the handle? Why the 7/16" cut out in the base? Is that how he came up with the 5 degrees? Also what angle do you think he used on the other end of the piece he made that fits in the 3/4" Dado? to prop up the other end?

beeg · Post by **beeg** » Wed Jul 23, 2008 4:22 pm

NuHobby.
Was the piece to big to fit on the joiner?

Charlese
How abut using carpet tape, to tape the thinner pieces to a thicker board? A Drew A. suggestion.

charlese · Post by **charlese** » Thu Jul 24, 2008 12:20 am

beeg wrote:
Charlese
How abut using carpet tape, to tape the thinner pieces to a thicker board? A Drew A. suggestion.

Thanks for the reminder! This is a good suggestion! I've not used a carrier board as yet as my planer will go to 1/8" with a stop at that depth. Next time I will make a carrier board with both double sided tape and a rear cleat. I'll let you know how it works.

nuhobby · Post by **nuhobby** » Thu Jul 24, 2008 11:00 am

Hi All,

Thanks for commments so far. I used the conical-sander method "pre-emptively" on 4-inch wide pieces since I didn't want to rick tearing out some fine figure on my jointer. Also I wanted the 2 halves of the resaw to be exactly the same thickness for book-matching.

I think my main curiosity is about sanding in general: When you have lower or higher grit, is there any basic characteristic about the sawdust that changes (besides amount of material removed)? I'm wondering if 150 grit was fine enough to make more airborne dust, and I could have been a little tidier with 80 grit?

charlese · Post by **charlese** » Thu Jul 24, 2008 11:46 am

nuhobby wrote: I think my main curiosity is about sanding in general: When you have lower or higher grit, is there any basic characteristic about the sawdust that changes (besides amount of material removed)? I'm wondering if 150 grit was fine enough to make more airborne dust, and I could have been a little tidier with 80 grit?

My thoughts on that issue (from my experiences in vertical conical sanding):
a) The sawdust does change, but my guess is most of the change is in volume.
b) I couldn't tell if the dust from 80 grit is larger (measured in microns), but the volume of dust increased. At least, I perceived it was greater.
c) Also, as I remember, the more coarse the grit - the farther dust is thrown, (with more velocity?) making it more difficult to catch.

beeg · Post by **beeg** » Sat Jul 26, 2008 12:26 am

I think you should have started with the courser grit, to remove the saw marks. Then the finer grits to smooth out the surface. The dust volume I think would depend upon that amount of surface your removing.

But using the finer grit to start, It would just take more passes.

carlray · Post by **carlray** » Sat Jul 26, 2008 9:27 am

By not using progressively finer sandpaper you risk burning the wood or project by generating too much heat. A coarser grit will get it to the desired thickness quicker, then you can switch to the finer grit for a few final passes to bring out the grain and finish sand it.

I am guilty of trying to use what is on the machine to save time but if it is a large project then I have found it is much quicker and easier to change grits progressively for the final outcome. Always a compromise.

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(Conical) Thickness Sanding, a la Session #14

(Conical) Thickness Sanding, a la Session #14

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