PDA

View Full Version : Thickness planing top/back



SeanB1
03-11-2016, 06:28 AM
Hi folks,

I know this must have been discussed here but I didn't find any results in my searches.

I'm wondering about suggestions for holding or clamping for hand planing to thickness my wood. I have and am using a shooting board but it's unreliable at holding larger pieces like a top or back. It seems to work well for bracing stock, etc.

I read somewhere a suggestion of glueing sandpaper to a shooting board. Do you just clamp and move the wood end for end or do you have a great idea to share for holding the wood down?

Thanks for any help!

Sean

greenscoe
03-11-2016, 07:04 AM
I'm sure there are several ways of doing this. I don't have a drum sander and have thicknessed all my wood using a small plane (Stanley 220) and scraper (Stanley 80). I've made about 20 instruments.

I use 6" Irwin F clamps: I fasten one end of the wood to my bench top with 2 clamps and then plane away from the clamps. The wood is then turned around and the wood planed in the opposite direction, again away from the clamps. To reduce tearing, it's often necessary to plane diagonally, and one direction may be particularly bad in this regard. It's necessary to use a sharp plane, finely set. Sometimes a scraper will prove a better tool if the wood is very prone to tearing. The scraper should be sharpened periodically and set to remove a little at a time. Clearly it's also necessary to check progress regularly to ensure the wood is thicknessed evenly.

For anyone who has not done it: if the plane snags and you are planing towards the clamp (think sides) the wood can rear up and snap!

pointpergame
03-11-2016, 09:20 AM
Harpsichords, my once major instrument, have long, narrow spruce planks. It's fairly easy to do what greenscoe suggests. Clamp down the near end and plane away. Reverse the "plank" but...now chances are, you're planing against the grain. Even the sharpest, most perfectly-set, world class plane can't prevent tear-out in this case. Or even if it can, it's not worth the risk of losing a great soundboard. So you have to clamp the far end and plane in the direction of the clamp. For this, a well-lubricated #6 to #8 jointer plane is the perfect weapon. With all that length, it's pretty hard for the board to buck.

The problem with this is the loss of continuity on the stroke and possibly a small hump in the middle. ( I get very finicky about this kind of stuff. Who knows, maybe a hump is the middle is good for sound? But I want perfection on my terms ) For guitar, dulcimer, uke, etc., soundboards I have three strategies.
1) Leave extra length or extra width for clamping.

2) Use extra width ( or length ) and CAREFULLY nail through the waste to a baseboard, sinking the brad heads enough to avoid trashing that perfect plane iron. You can also glue the waste to a baseboard then cut the soundboard away with a #11 Xcacto knife or equivalent. Or glue it down with a piece of, say, newsprint, underneath so you can slice the finished soundboard free.

3) My favorite method that works most of the time, especially for an oddly-shaped board, is to cleat it all around to a perfectly flat baseboard. The baseboard clamps easily on a jointer's bench. If the cleats are glued down instead of nailed, again, you can avoid the danger of trashing a plane iron with the head of a brad.

powdrell
03-11-2016, 09:25 AM
Masking tape and CA. Tape onto bench surface, tape on board, CA tape together. Pull up tape when done, repeat. Much better than 2 sided tape 'cause it's thinner, easy to remove. Good luck!

pointpergame
03-11-2016, 03:05 PM
Masking tape and CA. Tape onto bench surface, tape on board, CA tape together. Pull up tape when done, repeat. Much better than 2 sided tape 'cause it's thinner, easy to remove. Good luck!

That's a good one, too. Have to give a little thought to tear out if it's spruce when you remove the tape.

SeanB1
03-11-2016, 05:06 PM
These are great ideas. Thanks Folks!

Bob Orr
03-12-2016, 07:51 AM
Masking tape and CA. Tape onto bench surface, tape on board, CA tape together. Pull up tape when done, repeat. Much better than 2 sided tape 'cause it's thinner, easy to remove. Good luck!

+1 for this method, very secure and nothing to get in the way.

Titchtheclown
03-12-2016, 02:00 PM
I use regular double sided tape, a nonpadded variety which is thinner than a single layer of masking tape, let alone two. I get nervous around ca glue and gueing things down. I may try that ca glue trick when i run out of double sided tape. Cleaning off the double sided tape is a lottery. Sometimes it stays on the desk sometimes it stays on the work piece.

Michael N.
03-12-2016, 11:11 PM
The fastest method that I've found is to build a planing 'holder' :

http://i56.photobucket.com/albums/g193/mignal/000_0001_zps04594ec1.jpg (http://s56.photobucket.com/user/mignal/media/000_0001_zps04594ec1.jpg.html)

I have another for doing backs and tops. It only works if you plane straight across the grain, don't attempt to plane with the grain. I can thickness a Rosewood guitar back in around 15 minutes (that's going from 5.5 mm's down to 2.5 mm's) using this method. I do each half of the back separately, then join but leave a touch of thickness for scraping.
You also need to know the workings and use of a jack plane, the difference between that and the smoother to become really efficient at thicknessing with planes. I use wooden planes for the bulk removal because they are light in weight. I only switch to a metal smoother for the last few tenths of a mm. So many buy an expensive plane thinking it will be 'easy'. They then find that it takes them 3 or 4 hours to thickness a back. I've even had so called pro luthiers tell me that it takes 'all day' to thickness back, sides and a top. Those are the people that switched to a thickness sander, simply because they didn't understand the use of a jack plane. They were probably clamping and planing away. That's a big time sink too.

Bob Orr
03-13-2016, 01:58 AM
I use regular double sided tape, a nonpadded variety which is thinner than a single layer of masking tape, let alone two. I get nervous around ca glue and gueing things down. I may try that ca glue trick when i run out of double sided tape. Cleaning off the double sided tape is a lottery. Sometimes it stays on the desk sometimes it stays on the work piece.

That is the advantage of the ca and masking tape method. very easy to remove the masking tape and no lifting of fibres in my experience.
Bob

Red Cliff
03-13-2016, 02:23 PM
Toggle clamps fastened to some hardboard.

SeanB1
03-13-2016, 02:46 PM
So with the toggle clamps, do you just fasten 1 end with 2 clamps?

Michael N.
03-13-2016, 11:59 PM
I simply don't understand why you are trying to fix down something the size of a ukulele top or back plate. By the time you've allowed room for the clamps and room for the metal of the plane behind the blade there won't be a whole lot of wood left to plane. You'll be constantly having to clamp and unclamp. Think about it, it doesn't have any logic to it at all. The sides might be a different issue due to their length. Even then you'll be constantly having to flip and unclamp, constantly measuring their thickness. Either build a planing holder or use the tape method. The planing holder is much quick in use but takes time to make. The tape is slower in use but there's nothing to make.

mvinsel
03-14-2016, 10:21 AM
Not having a big drum sander or room for one, I use a simple jig from two pieces of plywood. One holds the piece, with just a small piece of wood fore and aft glued down to keep the top that I'm sanding from sliding. and has high side rails that the smaller sanding part slides in between. The other piece gets sandpaper fixed to it with thin double stick tape used by picture framers, and has two side rails that are the thickness of the final piece plus the sandpaper, and a handle on the back side. So you just pop the top piece in, slide the sander back and forth a few minutes, and get a nice flat top piece.

Here's a picture:
89278

-Vinnie in Juneau

Timbuck
03-14-2016, 01:08 PM
I've never planed or scraped anything to thickness yet..I built a thickness sander first and then started building ..I believe it's called "forward planning" ;)

Red Cliff
03-14-2016, 01:52 PM
Yeah, the toggle clamp approach has some draw backs, but at the time I had no space for planing boards and can use the same set-up for backs, sides, guitars, ukes. I guess turning the wood around would become a bit tedious for a pro builder, but for an amateur it adds like 5 minutes to the process so doesn't bother me that much.