Cambering a Toothing iron

[bacchanal]

Hi all,

I am writing to ask for some advice, from those of you who use toothing irons regularly. I make musical instruments, and find a toothing iron to be an excellent tool to take more stubborn woods down to thickness (usually to around 2mm). I then use a scraper to get rid of the toothing marks.

I recently learned about cambering my plane irons, and have had wonderful results. I can't see myself going back to a straight blade ever again.

Would there be any cons to also cambering my toothing iron? (I use it on a no. 5 jack plane). I am thinking it could help with greater accuracy of flatness, but perhaps given the tooth's, there may well be a reason not to camber it, that I do not know...
Could anybody with more knowledge on this matter fill me in on the pro's and cons of this?

Any advice would be very gratefully received.
Theo

 

[ED65]

I can't see that cambering would help with one of these used for this purpose (I'm thinking it's an either/or proposition). But if you have plenty of length left in the toothed portion of your iron it won't hurt much to try it and see and if it's not helpful to go back to straight across.

 

[Ttrees]

Does anyone who uses the cap iron to its full effect have the need for a toothing iron ?
Bacchanal, I suggest that you look up David Weaver (David W on utube) and his efforts to make it widely known about the cap iron effect.
I recently made a toothing iron by accident (hitting a staple), and I cannot see why anyone would want one for fine work.

Tom

 

[Racers]

I needed a scraper plane on some Box recently even with a razor sharp blade and the merest glint of blade exposed it still tore out.
Luckily my infill scraper plane came to the rescue.

DSCF0011 by pete maddex, on Flickr


Pete

 

[dzj]

I used one a few months ago, when flattening my benchtop. No camber.
The Jack resulted in tear out, a smoother worked well, but it was slow.
A high angle toothing plane worked best in this instance. A few passes with a card scraper
after and all was well.
Not a finish ready surface, but adequate for a workbench.

 

[bugbear]

Would there be any cons to also cambering my toothing iron?

I have no answer for you, but that is the most interesting question I've seen in months! =D>

BugBear

 

[matthewwh]

The only con I can see is that you would end up with toothed valleys, so when you scrape you will end up with a mixture of smoothed high spots and tooth marks remaining in the hollows - i.e. you'll end up spending longer scraping than you would have without the camber.

Then again, if you've got a scraper as nice as Pete's then that could be a happy problem to have.

 

[Ttrees]

I needed a scraper plane on some Box recently even with a razor sharp blade and the merest glint of blade exposed it still tore out.
Luckily my infill scraper plane came to the rescue.

DSCF0011 by pete maddex, on Flickr


Pete

Interesting, I've not had any experience with tearout since I've learned to set the cap iron.
So much so, that find your comment hard to believe.
I'll admit only trying this on iroko, meranti, sapelle, afrormosia, but these can tearout really bad if the caps not set.

Have you experimented with the angle of the leading edge and the relationship of it, in regards to the closeness of it to be set?
It can be done with the original leading edge angle, but it has to be closer than one honed at around 50 degrees.

What angle do you like best ?

Tom

 

[profchris]

I think there is a particular problem with musical instrument making. If you've taken your wood to 2mm thick and are now doing the final thicknessing down to 1.8mm, then even a little tearout can spoil all the work so far! Plus the plate will inevitably flex a little as you plane (though I know some luthiers have vacuum hold-down systems, those might be OK), and the plane can catch a little as you go. On top of that, we're often using highly figured wood.

So to protect the several hours of investment at this point, I use a toothed blade set just off the vertical in my woodie smoother plane body, working across the grain otherwise it clogs with strings of wood. This takes off the excess fast without risking damage, and I finish off with a scraper.

I don't think a camber would help my scraper plane - but I guess it might if using the blade at a conventional angle.

 

[Ttrees]

Any luthier who thickness planes their plates, their bench should not flex ..
Personal opinion though

 

[Derek Cohen (Perth Oz)]

The reason to camber a smoother-type blade is to prevent tracks. A toothing plane is all about making tracks - very fine ones. Therefore, it makes little sense to camber a toothing blade in this regard.

On the other hand ...

How deep can one use a toothing blade? My limited experience says not as deep as a jack with cambered blade. Cambering a toothing blade to create a narrower blade to plane deeper may be reasonable.

Regards from Perth

Derek

 

[Racers]

I needed a scraper plane on some Box recently even with a razor sharp blade and the merest glint of blade exposed it still tore out.
Luckily my infill scraper plane came to the rescue.

DSCF0011 by pete maddex, on Flickr


Pete

Interesting, I've not had any experience with tearout since I've learned to set the cap iron.
So much so, that find your comment hard to believe.
I'll admit only trying this on iroko, meranti, sapelle, afrormosia, but these can tearout really bad if the caps not set.

Have you experimented with the angle of the leading edge and the relationship of it, in regards to the closeness of it to be set?
It can be done with the original leading edge angle, but it has to be closer than one honed at around 50 degrees.

What angle do you like best ?

Tom

It was a slice of box about 7mm thick from small branch, I only got two blanks out of the piece.
It had side branches so the grain went in all directions and after resharpening the blade and adjusting the cap iron made no difference I got my scraper plane out, sharpened it until I had a burr on the blade and it worked a treat.
I have successfully used the cap iron before on difficult woods like burr silver birch which is soft and difficult to plain.

I made the scraper plane years ago and its a lifesaver.

Back to the original question I think no canber because the different depths of the grooves.

Prte

 

[Droogs]

Hi Bachanal, very good question. I use a toothing plane on almost every project I do. My favourite is one I got from Dodge of this parish. The toothing plane was basically developed for surface preperation by ebiniestes to give better mechanical keying of hide glues and for allowing you to remove often quite a large amount of stock material without causing tearout on wild grain woods (particularly tropical hardwoods that were all the rage in the 1700s) after sawing to size. It's main purpose is to give you a level straight surface onto which you can then immediately apply glue to. It's very design, in that it has lots of points that take of strings of wood rather than shavings and leaves score marks negates any need for a camber. As said above by Derek the purpose of cambering a plane blade is to eliminate the very thing a toothing plane is designed to produce.
Toothing planes come in various sizes and at different bed angles, usually the lower the angle - the larger the teeth and the more you can hog off with each stroke. So a lower angle toothing plane is used in much the same way a highly cambered #5 would be for fast removeal and then you would switch to a higher angle plane to finish off both the veneer piece and the substrate. Remembering the substrate would be made with much cheaper and usually softer wood and would only be toothed where the venner is to be applied as a key for the glue.
When it comes to using modern man-made boards and glues (PVA) etc with the micro thin cut veneers we now have there is no real need for using the toothing plane at all. It does shine when using your own sawn veneers or contruction thickness veneers and you really don't want the veneer to move during cramping up.

So really long answer short - no leave it as it is and get rid of the tracks using a scraper like great great great great grandad did

You can see a really enjoyable article here:
https://anthonyhaycabinetmaker.wordpres ... -our-time/


hth

 

[whiskywill]

Any luthier who thickness planes their plates, their bench should not flex ..
Personal opinion though

I use one of these.

Should I camber it?

 

[sunnybob]

As is often the case on this site , I had never heard of the item under discussion, and might have considered it an april fools if it wasnt november, so i did a quick surf and found this interesting (to me anyway) paragraph......


This toothed plane blade is for working wood with difficult grain and/or lots of knots. After surfacing with the toothed plane, the wood can then be worked flat relatively easily with a smoothing plane, scraper plane or a cabinet scraper.

The blade is not designed to be used in a normal bench plane however. The cutting angle of a bench plane is normally 45 - 50 degrees. But the body of a toothed plane is normally made to give a cutting angle of about 75 degrees, and so mounting this blade in a normal body will not give good results, as the higher cutting angle is needed to allow the blade to cut properly and reduce the chance of tear-out.

 

[AndyT]

We're starting to go round in circles here.
What Bob has just looked up, ie use of a toothed iron at near-vertical pitch, is relatively well known. Old toothed iron planes, like coffin smoothers but with the iron straight up, are not uncommon.

But the OP is asking about use of a toothed iron in an ordinary common pitch metal bench plane. Thus is something which was practically discovered/rediscovered fairly recently.

There was a long and useful discussion of it back in 2008, sparked by a demo by Deneb Pulchalski of Lie Nielsen.
This is the old thread, which may be of interest.

toothed-blades-for-bevel-down-planes-t25170.html

Jump to page 7 for the discussion of cambering a toothed iron.

 

[profchris]

As is often the case on this site , I had never heard of the item under discussion, and might have considered it an april fools if it wasnt november, so i did a quick surf and found this interesting (to me anyway) paragraph......


This toothed plane blade is for working wood with difficult grain and/or lots of knots. After surfacing with the toothed plane, the wood can then be worked flat relatively easily with a smoothing plane, scraper plane or a cabinet scraper.

The blade is not designed to be used in a normal bench plane however. The cutting angle of a bench plane is normally 45 - 50 degrees. But the body of a toothed plane is normally made to give a cutting angle of about 75 degrees, and so mounting this blade in a normal body will not give good results, as the higher cutting angle is needed to allow the blade to cut properly and reduce the chance of tear-out.

I'm not sure this is correct. I have a toothed blade for my Veritas apron block plane, and that works pretty well for small areas of squirrelly grain. However, if set too deep it can catch and tear the wood. The near-vertical blades don't run that risk.

BTW, my bench doesn't flex! But a 2mm thick board clamped at the edges can still flex in the middle if the plane blade hits some reversing grain. If I were more than a hobby maker I'd be building a vacuum hold down for planing.

 

[Ttrees]

That's why the cap iron is so useful !
Another unmentioned attribute of planing with the cap iron effect, is the ability to
clamp the work at one end only irregardless of grain pattern, and plane away from the clamped end.
This is important for very thin stock that needs to be flat against the bench.

I remember trying to clamp an Indian rosewood guitar fingerboard before...
I was planing it down to the bottom of the fret slots , it flexed and snapped at the
slots, lesson learned !.