Glue plane

[Staffan Hamala]

I've found a plane referred to as a glue plane. My suspicion is that it was used to rough up wood to make the glue stick better. What do you think?

It's about 20 cm, or 8 inches, long.

http://www.ludd.ltu.se/%7Estaham/plane1.jpghttp://www.ludd.ltu.se/%7Estaham/plane2.jpg

[Mark Stutz]

I've seen them more commonly referred to as toothing planes, and yes, they were used to prepare surfaces for hammer veneering with hot hide glue. Remember though, this was with shop sawn veneer, not the microscopically thin stuff availble commercially today. They can also be used to flatten very difficult grain. If you go to the old episodes of the Woodwright's Shop you can find an episode where Mack Headley, IIRC, demonstrates it's usage in making the veneer for the reproduction Seaton chest. I just picked one up at an auction and am anxious to try it.

Mark

[Staffan Hamala]

Thanks! I found the episode of the Woodwright's Shop. I think this plane will be useful for other things as well.

[Andrae Covington]

Thanks! I found the episode of the Woodwright's Shop. I think this plane will be useful for other things as well.

On youtube you can search for "Lie-Nielsen Toothed Blade Demonstration" or something similar, and see a video of Deneb Puchalaski from Lie Nielsen demonstrating a toothed blade in a low-angle jack plane to deal with difficult grain. Basically he uses the toothed blade to flatten the board down past the tearout from the scrub plane. Then he changes to a regular blade with a very light cut to smooth the toothed surface. Seems like it would be a good technique for curly maple etc.

[george wilson]

For what it's worth,Fine woodworking years ago did an article about the Department of Agriculture's study that showed that glue actually holds better on SMOOTH surfaces! Google it and see what you can dig up.

It could be that the glue surface is actually reduced by toothing,and the more important gripping power is getting the glue into intimate contact with the wood. I don't know.

I know it seems counter intuitive,but those were the findings. I never did tooth any surfaces on the large veneered harpsichord I made for Williamsburg in 1970. I glued mahogany crotch over a plain mahogany carcass with hide glue. It has never come loose anywhere in all these years.

This "harpsichord maker" fraud who lives in the area used contact cement on a piano(horrible workmanship) he made,and the veneer was coming up in big football size,and shape bubbles all over it within a 6 month period.

[David Weaver]

Thanks! I found the episode of the Woodwright's Shop. I think this plane will be useful for other things as well.

You could put a straight blade in it and use it to scrape, though I've always liked an iron with a hook for that a lot better.

If you have any japanese planes needing the bottom scraped (i say that sort of kidding, but you never know!), it would be useful for that with a straight iron, too.

To Georges point - when I started using hand planes, I wondered if there was such a thing as too smooth for the wood, but I have never had a butt joint on long grain come apart. I'm guessing that the moisture in whatever glue there is will find a way to swell the wood some and get a grip / become part of the top layers.

[john brenton]

For anyone that's interested there is a sweet Ulmia toother going on a popular auction site. Somebody put his name on the side of it but it's very rare to find a new-ish toothing plane.

[Rick Markham]

For what it's worth,Fine woodworking years ago did an article about the Department of Agriculture's study that showed that glue actually holds better on SMOOTH surfaces! Google it and see what you can dig up.

It could be that the glue surface is actually reduced by toothing,and the more important gripping power is getting the glue into intimate contact with the wood. I don't know.

I know it seems counter intuitive,but those were the findings. I never did tooth any surfaces on the large veneered harpsichord I made for Williamsburg in 1970. I glued mahogany crotch over a plain mahogany carcass with hide glue. It has never come loose anywhere in all these years.

This "harpsichord maker" fraud who lives in the area used contact cement on a piano(horrible workmanship) he made,and the veneer was coming up in big football size,and shape bubbles all over it within a 6 month period.

I think the original idea was that it would increase the surface area. But since wood is porous essentially all it does is reduce the area that is in contact between the surfaces. A non toothed surface will have more surface area in contact with the veneer. If you were gluing a super smooth non porous surface (a plastic) roughing it up would help the glue stick. But since wood is super porous it already has a huge surface area.

I'm not surprised your craftsmanship hasn't come apart George... Something tells me your tools will outlive many many many generations to come. (which by the way, has to be a pretty cool feeling) Just goes to show you, shortcuts are never really worth the time they "saved". Do it right the first time, and do it once! Take a short cut, and pay for it in the long run!

Staffan, Lee Valley makes a nice cabinet scraper with a toothed blade for scraping very difficult grain. My guess is that will be the best use for your horned wooden plane. Be careful not to break the teeth when sharpening your iron, Only forward and backwards... never sideways!

[george wilson]

It is good to leave a legacy. I should have been a stone cutter if I expect my stuff to last,though!!

[Andrae Covington]

I had forgotten, but R. Bruce Hoadley mentioned the same thing in Understanding Wood, but did not elaborate.

Here's the USDA study:
http://www.fpl.fs.fed.us/documnts/fpltn/fpltn-227-1957.pdf

The gist of it can be summarized in these two paragraphs:


Under good gluing conditions, smoothly planed surfaces have slightly stronger joints than tooth-planed surfaces on two of three species. The differences, however, are not great enough to conclude that tooth-planing weakens the joint to any marked extent.

Under conditions that normally produced starved joints, tooth-planed surfaces on two of the three species gave higher joint strength than smooth surfaces. The joints produced in this way were not so strong, however, as the smoothly planed joints made under good gluing conditions.
The testing was conducted with sitka spruce, white oak, and sugar maple, using hot animal glue.

[Rick Markham]

haha, true. Though I'm not sure you would have lasted as long as you have... I'm sure that craft takes a quick toll on it's craftsmen. Back breaking dirty work to say the least.

I have my suspicions yours will live on for longer than most... Your tools you have made all have an artistic value, of which even non craftsmen can tell they aren't "ordinary or common" Yeah, insturments allways will require repair as they age... hopefully part of your legacy will be leaving your knowledge with people to pass it along so one day there is a Luthier with the proper skills to fix your life's work.

People tend to take care of high end instruments and tools, Art always tends to be cherished and well cared for. I'm hoping one day to leave a few things behind myself that hopefully someone somewhere will enjoy :o

[Rick Markham]

I think a lot of it comes down to perception. Our perception of "smooth" is a limit of our senses (not a reality of the surface on a microscopic level.) No matter how smooth you make a wooden surface, if looked at under an electron microscope it's going to look like a giant sponge. Most glues work on a molecular level. There are plenty of areas for it to grab onto a super smooth wooden surface, even when we can't feel or see it.

Granted, if you starve any joint of glue it will weaken it. The toothed one would trap pockets of glue making it at least noticibly stronger than a smooth starved joint. I personally haven't ever had any luck starving a joint of glue, but then I don't skimp on the glue, and have learned that over tightening of clamps only causes warped joints and more headaches later.