Tuesday, March 28, 2017

Fixing and Fettling a Wooden Plow / Plough Plane - Part 3

Uh, Houston?  We have a problem.

Make that a few problems.  Last post I described getting the skates in line with each other.  Well, after plowing my test groove with the 1/2" iron, the rear skate was out of alignment again.
Front of rear skate (right) lifted
This next picture shows the skate not quite seated in its groove.  Enlarge the picture and you'll see a gap that shouldn't be there.
Arrow points to the gap
All it took was a tap with a wooden hammer to re-seat it.  But I found out that the simple act of tapping in the wedge when setting the iron was enough to knock it out-of-whack again.  I'm sure the act of planing would do it, too.

I have to think about what to do about this, but if anybody cares to comment, I"m open for suggestions.  I'm thinking I have two options: allow the skate to lift and from that position file it down to be even with the front skate (don't like this idea at all), or plug and re-drill the screw holes to make the skate more snug in its groove in the plane body.

UPDATE: I had failed to tighten the skate screws all the way down.  The screws are a little off center in the direction that should pull the skate into its groove, so I hope this is all I needed.  We'll see.
Screw holes are a little off center from the skate's countersunk holes,
which should pull the skate upward

The front of the rear skate is in line with the plane body's bed angle.  The lower front of it extends about 1/16" further than the upper front portion and is filed to a point so that the groove in the back of the irons can mate with it.
Portion of skate filed to a point - a little proud of the rest of the front of the skate
Here it is at a different angle (from above and to the right) to try to show the angle filed on the front of it.
The point filed on the front of the rear skate
The backs of the irons have a groove that sits on the pointed front of that skate.
Backs of the irons showing the groove that mates with the skate
Looking through the mortise hole that houses the iron and wedge, you can see that the pointed portion of the skate should be proud of the rear wall of the mortise.
Tip of rear skate just visible - it's just proud of the rear wall of the mortise
I think the purpose of the pointed front of the rear skate is twofold.  First, it keeps the iron from moving laterally.  The back ends of these irons are typically 5/8" wide, but the mortise for the wedge and iron is a little bit wider, so there is a little wiggle room.  Seating the groove of the iron onto the point of the skate keeps is steady.  The second reason for the skate shape is to center the iron.  When the iron, plane body and skate are properly constructed the iron will be forced to the center.  Not that it matters if the iron is perfectly centered though, because the movable fence determines its position on the work piece.

Regarding the irons I purchased, the jury is out.
My original 1/2" iron at top, and new (to me) irons in box
Plow plane irons are numbered #1 through #8 with sizes 1/8", 3/16", 1/4", 5/16", 3/8", 7/16", 1/2", and 5/8" respectively.  So my 1/2" iron is a #7.  I purchased the smallest 5 sizes.  Unfortunately, only one of them is close to the nominal size.
#1 iron by Dwights French & Co. should be 1/8", but is 11/64", way oversize!!
#2 iron by Wm. Ash & Co. should be 3/16", but is 13/64"
#3 iron by Peugeot Freres should be 1/4" and is more than 1/64" oversize
#4 by Meaney (or maybe Heaney, or Beaney?) & Wood should be 5/16" and is 1/64" oversize
#5 iron by James Cam is close to right size at a strong 3/8"
I've read that British plough plane irons often have a different taper than American made irons.  Dwights French is American, Wm. Ash and James Cam are British and Peugeot is French (could not find info on the #4 iron), so all bets are off that these irons will all have similar tapers to my Ohio Tool iron and fit in the Ohio Tool plane with the current wedge.

Here are the irons from the back end, highlighting how different they are.
All very different: #5, 4, 3, 2, 1 and my #7
Blurry pic of back ends in profile.  How are you supposed to strike the thin ones to advance the iron?
#2 iron is already folded over (see individual pic above)
The business ends - some different shapes
The grooves - all very different again
Well, the jury has come back.  I sent these irons back to the seller for a refund.  I contacted Josh at Hyperkitten, but he's got no American made plow irons right now.  Patrick at Supertool is trying to sell me on an English set.  Gotta keep looking.

Regarding the irons, I've got so many questions!
  • How well does the groove need to fit the point of the skate?
  • Should the tapered length of the irons be perfectly flat on back and front (grooved side) to mate with the plane bed and wedge?  I thought I read somewhere that the tapered length is typically concave on the grooved side.  If this is true, then why?
Bevel (grooved) side is a little concave
Back is fairly straight, but not exactly
(Man, is it tough getting decent photos of this!)
  • As a tapered iron wears down, it gets thinner, meaning the wedge will sit lower in the plane. This wedge has a groove to match with the plane body to eject shavings.  Does this matter?
This little curve at bottom of wedge is already lower than the matching curve in the plane body
Garret Hack's excellent book, "The Hand Plane Book" doesn't give specific information about my questions.  I don't know where to find the answers, even after searching the internet.  I wish there was somebody to talk to about this stuff, but this knowledge is rapidly being lost.

BTW, just to record this somewhere, My 1/2" iron's cutting width is dead-on 1/2" (0.498") and it is a little narrower at the grooved side for clearance in the cut.  At its thickest point (where the bevel starts), the iron is just shy of 5/16" thick (0.309"), three inches back from there it is just under 1/4" (0.242") thick and 3 more inches back it is about 3/16" (0.185").  A little trig gives a taper angle of 1.2°.

I'll post more about this when I finally get a better set of irons.  Then I'll try fitting them and may have to make new wedges.  I probably need a new wedge for the 1/2" iron anyway, as it's pretty mangled where you tap it out.


  1. Hi Matt,
    you shouldn't need a wedge for each iron. The irons for that plow should all be the same thickness with different individual widths. I take it you're adopting your herd of irons?
    I checked my Mike Dunbar tool book and my other plane books and there isn't anything helpful there. It's frustrating having questions and no answers. But sometimes it's fun to find them out for yourself.

    1. I sent the small herd of irons back to the dealer. They were all very different from each other and were just too far gone to be useful. I've been contacting other dealers to see what's available.

      I contacted Bill Schenher of the "http://www.billyslittlebench.com/" blog. He answered some of my questions. I just need to work with the irons available to make them work with my plane. Looking forward to it. Just gotta find some decent irons.