Dumb shoulder plane question

[Gary Herrmann]

I'm going to hone my shoulder plane iron tonight or tomorrow. I'm not an expert sharpener, so I use a honing jig. I've got the LV MK II. Obviously it won't work on the side bevels. I'll try to hone them by hand and see how it goes.

Heres my question. I assume the majority of the cutting work is done by the leading edge of the iron, and the sides clean up the dado. Obviously, they're good for getting right up to the dado wall. However, do the sides need to be as sharp as the leading edge? I'm asking in case I don't do a stellar job on the sides.

Thanx.

[Steve Beadle]

Someone more experienced than I will correct me if I am wrong, but I wouldn't try to hone the sides of the blade at all. The cutting is done by the bottom edge, clear out to the sides. On a shoulder plane, the sides of the blade should stand proud of the left and right cheeks of the plane by a minute amount--say, 1/64" or even less. You don't want to be removing any of the width of the blade unless it's too wide for the plane body!

[Mike Wenzloff]

As Steve says, the sides are not sharpened. Should save a bit of frustration...

With a shoulder plane, the sides of the dado won't be touched per se. That's why you need a pair of side rabbet planes <g> <G>...Old Stanley, new LN or great old woodies (if you can find a nice pair).

Even an actual dado plane, which a shoulder plane isn't, will not clean up the sides once cut.

Mike

[Mark Singer]

The sides should be honed to just over the width of the mouth....many companies like LN will leave the iron wide to allow for individual preference. Or you can try by setting it ....just slide it just over flush and see how it planes...that will tell you if you are there.

[Gary Herrmann]

for the information guys. I was somewhat hesitant to hone the sides, now I'm glad to know I shouldn't.

The dado example was a poor one. First thing that popped into my head while my wife was calling me for dinner. Penne Arabiata...

However, it does make me think about looking for rabbet planes for cleaning out dados. I've done it with a chisel before, but a plane would probably be easier and smoother.

More tools for the mounting list...

[Derek Cohen]

Hi Gary

A little logic here is also helpful in shedding light on the side bevels of shoulder plane blades.

The purpose of the projection of the side bevel is to make sure that the blade gets right into the corner of the shoulder or rebate. If it did not do so, the corner is in danger of not being cut at 90 degrees.

A rabbet (rebate) plane does something similar, but its primary purpose to to remove as much waste as possible, and as quickly as possible, to create a rebate. So the rabbet plane cuts downward in a progression of layers. To keep the inner rabbet edge square/perpendicular the blade is flush against the side of the plane (i.e. no projection) and it uses a fence (for uniform width). It may use a spur if cutting across the grain. The mouth is wide and there is no attempt made to cut very finely.

Then along comes the shoulder plane. Whether you are using it to clean up the rabbet you have just cut, or trimming straight the shoulder of a mortise-and-tenon joint, its goal is to do this with precision (hence the small mouth and fine blade projection). It should do its job in one (or two) passes. In other words, it is not hogging away waste - which is the job left to the rabbet plane. If it attempted to do this, you would create a ragged inner edge since the side bevel would dig in all the way down.

Some shoulder planes cut well enough without a side bevel projection. Some do not have a side bevel on the blade (e.g. HNT Gordon shoulder planes). Whatever side projection you have, it is still cutting with the front bevel, not the side bevel. You end up with an undercut (hence you don't want to do too much of this, that is, treat it like a rabbet plane). And the smaller the side projection the better - a "poofteenth". Just enough to make the finest of undercuts.

Regards from Perth

Derek