Krenov style plane jams

[Jim Matthews]

I'm working my way through "someday" projects including a laminated Krenov style kit. I can take a shaving, and adjust thickness.

The problem is it frequently jams. The shaving looks like the corrugated layer in cardboard.

Backing off the cap iron makes no difference.

Before I adjust anything - what should I be looking over?

[Ben Ellenberger]

How tight is the mouth? That is another thing that can jam up shavings.

[Tom Trees]

As Ben said how tight is the mouth?
I would think this combined with a possibly higher bed angle, and possibly compounded again by a steep leading angle on the cap iron would cause this
to happen.
Is there chattering involved also, I would guess so.
If it is, that's what happens when you have a close set cap iron and a tight mouth on a Bailey.
The tight mouth being the main thing that leads folks to think the cap iron is too close, when for some timbers, it wouldn't be close enough atall.

I would wait to see what Derek says, as he has a range of planes with tight mouths and higher bed angles.
I wonder if he finds a use for a tight mouth, since he does some rather delicate work.
Chamfers on proud tenons maybe?

Tom

[Andrew Hughes]

My guess is the chip breaker is not shaped correctly as in perfectly matched with the blade. If your plane doesn’t have one then i don’t know ?

My Krenov plane has a large mouth opening I’ve not found that to matter much. It’s the iron and chip breaker I focus on.
I think others call it a cap iron? Weird

[Jim Matthews]

My guess is the chip breaker is not shaped correctly as in perfectly matched with the blade.

Blade and cap iron from a well known contemporary maker - no gaps in the mating surfaces.

I have smoothed the milled faces where the edges were ground. The consensus is the mouth needs more clearance.

[Derek Cohen]

I posted this reply on the WoodCentral forum ....


Jim, basically, there is no room for the shavings to escape, and they are becoming trapped between the chipbreaker and the escapement.
The choices are these:

1. Change the escapement, or

2. Change the chipbreaker.

The escapement can be dealt with in one of two ways. David suggests that you make the wear steeper. I do not think that the Krenov plane has a traditional wear.

The wear might look like this ...

https://brfinewoodworking.com/wp-content/uploads/2017/04/WoodenPlaneGeometry02.jpg

... and David is suggesting you do this (this is a high angle bed Krenov plane I built quite a while back). Note the wear is a higher 90 degrees here ...

http://www.inthewoodshop.com/ShopMadeTools/BuildingaKrenovSmoother_html_4d0ead90.jpg

Many Krenov-style planes are not built with a traditional wear, but instead with an escapement that ends in an angled corner. This cannot be opened for fear of opening the mouth. I built a 60 degree infill with an escapement like this ... of course, in that plane, there was a steel sole as well.

https://i.postimg.cc/fW0RjJhV/The-Brese-Small-Smoother-Kit-html-28a5c2c2.jpg

To maximise the escapement space, where it was not possible to make this shallower, what I did instead was to hollow out the escapement ...

https://i.postimg.cc/4NkN8sJB/The-Brese-Small-Smoother-Kit-html-m7e706fc7.jpg

You could do this using a scraper ala the square-ended chisel of Bill Carter (grind the end of a chisel square and use it as a push scraper).

2. Change the chipbreaker: Either pull the chipbreaker back, or lower the leading edge of the chipbreaker. Both these provide more clearance. Neither eideas are great for tearout control, although the latter idea is feasible still ... reduce the thickness of the chipbreaker, but leave the leading edge steep..

Regards from Perth

Derek

[David Bassett]

An experiment, (NOT a Fix!), occurs to me. To confirm a clearance problem between the chip-breaker and the, erh*, wear you could pull the chip-breaker back and experiment in a "nice" piece of wood. Good luck (and please report back.)

(* I'm so far from an expert I'm learning from these other posts. It just occurs to me an additional data point won't hurt before you start carving on the plane body....)

[Jim Matthews]

Thanks to everyone for setting me on the right track.

Most of the problems were solved by smoothing interior surfaces and refitting the wedge.
The plane was assembled by the previous owner with both skew in the mouth and twist in the base. No wonder they gave up.

It *looked* fine.

Knenov plane rescue https://imgur.com/gallery/5Bo60Ip

https://i.imgur.com/Z54o68o.jpg