Coffin Smoother

[George Bledsoe]

I bought a couple of old wooden planes on e-bay. One is an old coffin smoother I think, it was beat up pretty bad but I thought it would be fun to fix (I have no idea why). I cut off the damaged bottom and replaced it with a new piece of beech. Re-cut the throat opening and cleaned it up good. I sharpened the blade and flattened the chip breaker and gave it a try. It will cut good but it keeps clogging up with shavings. I am not sure what is causing it to clog I don't want to joint the bottom to much and have to big of a blade opening. It is about 3/8 now but I have nothing to compare it too. It really is just for fun but I would like to see if I can get this going (again, why I have no idea) but now it has become a CHALLENGE :confused:

I will entertain all your words of advice.

Thanks

[Jerry Palmer]

You don't say how thick of shavings you're taking so it is really hard to say exactly what the problem might be.

The important part of the mouth opening is the space in front of the edge of the blade. Too big and it doesn't sufficiently support the wood fibers being cut. Too small and it will clog.

Not to say that the problem is definitely a too small mouth. Could be too great a depth for the mouth opening as well as an improperly spaced chip breaker. If the cutting depth is too great, the mouth will open more as the iron is retracted.

The chip breaker needs to be set pretty close to the cutting edge of the blade. That the plane has a chip breaker indicates it is a bevel up plane. On my metal planes I set the chip breaker about 1/16" from the cutting edge. IMO going closer to that doesn't make a lot of difference since if you're takeing shavings thin enough to believe you need it that close, you really don't even need a chip breaker as the super thin shavings will bend up and out of the way just based on the angle of the blade.

[Rob Millard]

George,

My first thought is are the shavings hitting the wedge? As far as the throat opening goes, I find that a super tight throat has no effect on the quality of the cut. On my standard Baliey type metal planes I set the frog so as to give maximum support to the iron, with no regard to the throat opening. On the wooden planes I've made, the throats are quite large, yet they will produce a shaving equal in every way to my finely set LN 4 1/2. Bed angle and rigidity are far more important in obtaining a good cut, than a throat opening.
Rob Millard

[Louis Bois]

George,

Another possible problem area could be that there's too much wood in front of the blade (see diagram). I've run into this problem on a few occasions where the sole was mended by adding a new section. The problem was easily remedied by filing away a more acute angle to open up the clearance inside the mouth. By doing this, you effectively don't change the mouth opening on the bottom of the plane.

You may also want to re-examine your wedge to make sure the leading edge sits firmly on the blade cap...and of course, also make sure the blade cap is properly mated to the blade.

Hope this helps.

[Leif Hanson]

Excellent suggestions so far.

One problem I've also had is the chips gathering underneath or at the outside corners of the blade. The slightest malformation of that area can catch a few slivers, then they compound the problem and pretty soon the whole thing is plugged up.

Re-examine the iron and make sure it's bedding across the opening evenly. To do that, take some Sight-Black or soot from a burning candle and coat the bottom of the blade and chipbreaker assembly. Gently put it into place, trying not to get the carbon all over the place, then drive the wedge in. Remove the whole affair - gently again, so as not to smear the carbon black around - and you should see black spots where the iron is in contact with the bed and bare wood where it isn't.

From there you can use a planemaker's float to remove the high spots, and try the process all over again.

Note - if you don't have a float, you can make one using these instructions (http://www.norsewoodsmith.com/img/float/Floats.htm), or another method is to take a cheap chisel and anneal it, then cut the end off at 90 degrees. Re-harden it, but don't temper it - leave it hard, and use it as a scraper. This is an alternate method to planemaker's floats, and has been advocated by planemaker Bill Carter:

http://homepage.mac.com/davewe/PhotoAlbum2.html

http://handplane-central.alphalink.com.au/main.html

HTH
Leif

[George Bledsoe]

Louis

That is a fantastic drawing, I was thinking about perhaps changing that angle to allow shavings to leave the mouth area.