Talk to me about bevel up smoothing planes

**IanW** · 23rd September 2021, 10:27 AM

Originally Posted by Tom trees

A tight mouth will stop the plane from working, even with a fine shaving....

Tom, that is manifestly not true. If it were so the old shoulder or box-mitre planes with absurdly narrow mouths wouldn't work. I have a couple of planes with mouths so fine you can't really see a gap at all unless you put a strong light behind them, yet they can take 8-10 thou shavings easily. Most of us cannot resolve less than 0.2mm which is roughly 8 thousands of an inch, so a gap somewhere between 6 & 10 thou looks like no gap unless you shine light through it. I've made quite a few planes these last dozen years or so and spent a lot of time mucking about with mouths & escapements. What has been most instructive to me is making 3 smoothing planes to essentially the same pattern & having all 3 behave radically differently, initially.

FWIW, these are my ideas, which I'm perfectly happy to have contested. The mouth itself (i.e. the gap between the projecting tip of the blade & the edge of the sole) is not so important, as longs a it's wide enough for the thickest shavings to pass though, it's unlikely to be a source of trouble. You are unlikely to get a mouth finer than 15-20 thou on a typical old Bailey plane. It's the geometry of the area above the mouth opening that really matters. If the front of the mouth doesn't slope forward enough, so the gap between it & the cap-iron is too small, it can be a source of endless problems - shavings will tend to catch and not clear that first mm or so after the mouth smoothly & you'll get choking problems. These can manifest only occasionally or constantly, depending on the wood you're planing and it can be quite independant of cap-iron angle. The angle at which the cap-iron meets the blade is also important, of course & needs to be in the ball-park for the wood you are planing. These two factors have the biggest impact on how shavings exit, in my experience

Down here we tend to work with a very wide range of woods in terms of their hardness & planeability & I'm afraid there is no one-size fits all, or if there is, it has eluded me. For some of the hard eucalypts & acacias I work with, a really close-set cap-iron can be counter-productive. If you try to take decent thickness shavings the hard fibres seem to be able to force their way under the best-fitting cap-irons and that, of course does no good whatever for your plane's performance. For these woods, a compromise setting of 0.5mm or even a bit more works best - minimal tear-out, all else being equal, and you can get the job done.

Even with the best of what I call 'real' cabinet-grade woods things can vary. "Queensland Maple" (Flindersia brayleyana) is one of the finest cabinet woods in the world, and also one of the most variable. It varies in hardness (old growth vs younger trees) and has a huge range of figure. It's usually easy to plane with a close-set cap-iron no matter how wild the figure, but occasionally I've struck pieces that have defied my best set-up planes & I retreat to other methods. I very rarely use my scraping plane nowadays, it's almost like conceding defeat, but there are some pieces of some woods where it's the most efficient way to get where I want to be.

I suggest to any newbie that you don't get too hung up on cap-iron settings to start with. A moderately- coarse setting (we were taught "a 32nd" which is roughly 0.8mm) works well enough on reasonable wood and will give you the least trouble. As you become more proficient at sharpening and generally setting up your planes (getting the cap-iron meeting angle right is a major factor), you can set it closer to 0.5mm and sneak it up closer still as the situations demand. It all becomes second nature after a while, you'll get to know your planes (they're like people, they all have their quirks & character, especially the old ones), your techniques will develop & you'll wonder what the fuss was all about!

Cheers,

PS. Apart from planing highly figured woods, there aren't that many situations in general cabinetmaking where you can't plane with the grain, which is the common-sense approach. The main exception I encounter is book-matched panels or table-top boards, where the grain necessarily runs in opposite directions at the join. Quite often I'm using such wildly-figured woods or there isn't enough contrary 'slope' to make much difference, but whatever the situation you can plane all but a half blade-width of each board from the best direction, & in many cases, you can plane over the join itself without tear-out even with a sub-optimally set plane (I managed it for 25 years or more

). Just occasionally, you'll strike big trouble, and that's where the super-set cap iron will be the ticket. But if you can't get your plane to play ball, you have other choices like scrapers (or even [shudder] abrasives). I reckon there's no shame in getting good results by whatever means are within your skill & tool set; when it's all done & dusted, it's impossible to tell from a typical casual inspection how you got there if your finishing is at all up to scratch.

**derekcohen** · 23rd September 2021, 10:58 AM

Ian, I believe that Tom was referring to a Stanley (or similar) plane using the chipbreaker to control tearout. He is correct to state that a tight mouth can impact negatively on smoothing. What happens here is that the chipbreaker blocks the escapement and shaving jam up. Open the mouth, and all is good.

Many years ago, I read an article by Chris Schwarz stating that he could not get a closed chipbreaker to work - all he achieved were wrinkly shaving, and that the plane was an effort to push. What he did not understand was that he had continued to set the mouth tight .. as one might when this was considered to be the main tearout control mechanism.

The mouth size has no positive effect when using a high cutting angle or a closed chipbreaker. HNT Gordon planes do have a tight mouth, but they also do not have a chipbreaker. It is not the mouth which has the positive effect, but the high cutting angle. You can test this out using a BU plane and pull the mouth open.

Regards from Perth

Derek

**Tom trees** · 23rd September 2021, 11:24 AM

I'll stand by what I've said about the tight mouth being the biggest factor in not getting the cap iron to work flawlessly.
Specifically talking about a Bailey style, and not any other plane,
so it's I who is likely being off topic I suppose.

I was doing just as you say before that, as tight a mouth as I could push, even bought a no.3 and scraper plane,
thinking I could plane the opposing ribbons with fine set, and blend with the no.80.

I know you can get fast at sharpening a scraper, David's video using the buffer is quite something impressive, compared to anything else I've seen, and I'm no slouch when I'm on the couch

What a lot of work even getting a tiny bit of tearout removed is such bother, if one works tropical timbers like you guys.
I had to take a break from the shed, as the iroko and even the easy to work by comparison red meranti dust was giving me irritation, and I was sweating it into myself.
Now I don't have dust all over myself, and dont have to sweat it out, as planing is easy now.

I have some stuff which is twice as heavy as the iroko though, don't know what it is, few hundred years old windows, probably lead paint on them. can take some shavings some time again.
This stuff is about as hard to plane as you will get, and I'd have no qualms whatsoever with making the cap iron steeper in this case, as the cap is too close for comfort really, if not very steep for this application, i.e 50 somethin degrees might likely be a bit low.

You can still comb the fibres with this setting, which shows up well in these old pictures.
I'll bet I could do a better job now, as I wouldn't be adverse to going steeper with the cap iron.
Kinda misleading to show, as one might get the impression that's still tearout, just noting that it works
on timbers likely equal to your most difficult examples.

I even bought a measuring scale to get an ID on this gorgeous timber.
Can't wait to work with it, from a very old building in town, never seen it anywhere else
Shown next to some meranti and iroko.

Tom

**IanW** · 23rd September 2021, 01:34 PM

Originally Posted by Tom trees

I'll stand by what I've said about the tight mouth being the biggest factor in not getting the cap iron to work flawlessly.....

Well Tom we are not really disagreeing, but I'll stand by what I said, too, and try to explin myself better. I said that it's not the mouth width per se that causes trouble, & I believe this is correct. At the point where the shaving enters the mouth, nothing has affected it yet, it's what happens to it after that that matters. If everything is sweet, the shaving hits the cap-iron while there is still sufficient stiffness in it & it is turned & passes up the throat. It may not if the front of the mouth is rough, or it doesn't slope away enough to provide adequate clearance, or the cap-iron meets the blade at too steep a tangent and you've got it set very close, or there is not sufficient stiffness of the shaving because it is too thin or the wood is too friable and doesn't hold together sufficiently as it's turned.

As I said, you can get a much thicker shaving through a tiny slit of a mouth than you may think. But remember, the shaving is compressed to some extent as it's cut, then de-compresses as the pressure is released on entering the mouth. If the front of a fine-ish mouth is at all rough, this can lead to catching and send the shaving astray so isn't pushed squarely into the chip-breaker, and obviously, opening the mouth will usually solve that problem. If the front of the mouth isn't sloped forward enough to cope with the decompression, that could also be a source of trouble. I suppose you could mount an argument that a very fine mouth might exacerbate the problem because the shaving will be more compressed as it enters the mouth - with a wide mouth there is more time for it to decompress and it doesn't matter anyway. But shaving de-compression is probably a minor factor when it comes to choking.

I guess I should have made it clearer that I was talking about my own infill planes, where I had total control of the geometry & was able to change each variable independently as I struggled to figure out why one plane did all it was supposed to do effortlessly & another behaved badly (with identical-sized mouths as far as I could see). However, I think my thesis would still hold up with Baileys. One of the problems with them is that the front of the mouth is usually as-cast, there has been no attempt to smooth the 'wear' & if you try to close the mouth too much the rough surface can contribute to shavings catching & choking. Opening it up fixes the problem because it greatly increases the clearance. On the two old Stanleys (both type 11) that I use every day, I don't think I could close the mouths enough to cause any trouble, there is still an awful lot of daylight with the frog as far forward as it will go, so I'm guessing you blokes are talking about somewhat less bruised & battered specimens...

Cheers,

**qwertyu** · 23rd September 2021, 06:55 PM

Been playing around with the chip breaker again and Ive opened the mouth so its huge now too. Today I am planing fiddleback redgum and fiddleback cypress.

With a perfectly set CB will the plane also be slightly more difficult to push compared to a plane with the CB set far (say 1+mm) away?

I am finding that when I have the CB set to cut with minimal tear out its harder to push. When I back the CB off a bit tear out increases. I wasnt looking as closely yesterday but today Ive been looking really closely and I can still see a tiny amount of tear out on the 'best setting'.

I'm also having trouble keeping the plane in the cut and having a continuous shaving. It is coming out when it tears out. I also cant take those super thin shavings like I was able to with a closed mouth and stock chipbreaker at 25deg - when I go really thin the plane seems to exit the cut (even on straight grained timber planing with the grain)

So now I am confused... I have the CB set to around 0.3-0.4mm and I am finding I its a bit harder to push, I still get a tiny amount of tear out, and cant make those shavings that float in the air when you throw it out.

Maybe I need a bigger microbevel? its about 54deg

**Tom trees** · 24th September 2021, 01:43 AM

That's a rather interesting comment about the wear in front of the mouth, Ian
I don't imagine that they way I had my planes set before ...as close as I could push,
(1/32" distance from edge, & cap honed @50),
was anywhere near the level of closeness as the mouths in your creations.

I'm finding it hard to imagine that it's the geometry of the plane casting which was making things so difficult,
and I've never even looked to see if it had any rough casting there, or witness polishing.

Some tearout, and serious warming of the sole was present, I didn't ask myself more questions than that.

All the best
Tom

**Tom trees** · 24th September 2021, 02:11 AM

Sounds kinda strange that it's not working perfectly Qwertyu
So the frog is all the way back now.

I can think of a few things
1. the frog got skewed when the plane was set with a tight mouth.
2. the leading edge of the cap iron may have had a remaining burr which got a bit bent, possibly due to same as above.
3. the camber if you like a teeny one, is not bang on gradual, and your cap iron setting figures is related to the centre of the iron.

Presuming you are getting the sign of the cap iron working, i.e straight shavings

Without being sure of your planing knowledge/technique...
Presuming you still are keeping things flat, Charlesworth has some of the best publications in regards to accurate planing,
should you be watching some other folk.
Even though there is nothing about cap iron's, his videos are purely based around technique, he could teach the dog how to plane accurately, and I haven't seen anyone come close to that, he won't see you wrong.

If you haven't watched Charlesworth, then I'm presuming that it could be something to do with the work methodology,
material deflection and related issues to that like cutter projection.

One might get all caught up in the pursuit of tearout elimination that the work is not flat,
and it's actually working, but can't plane down to the bottom of the pocket of torn grain as the work surrounding is still proud.

Another thing might be making sure the heel of the bevel of your cutter isn't rubbing on the work.

Did I say Charlesworth's videos are great?
Sounds like you have it to me, just one wee niggle or another.

Good luck
Tom

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