Compass Plane Irons

[custard]

The iron in my Stanley compass plane is much thinner than the irons I've come across in Record/Stanley bench planes.

Doesn't stop it doing a great job in all manor of timbers, but does anyone know why the iron is so thin?

 

[Phil Pascoe]

Maybe the iron thickness is governed by the size of the mouth? I don't know without going out to look, but iirc the mouth is quite tight.

 

[AndyT]

Same here. The iron in my Stanley 20 is 1.66 mm at the edge. ( 1.55mm at the top.) A little thinner than the iron on my No 3 (1.90 mm throughout.)

I guess that does make it easier to keep the mouth narrow, which means that the solid bit where the mouth is held onto the frog, can be as short as possible. That's a good thing, as it's a flat spot on the overall arc.

 

[PAC1]

I always assumed it was because otherwise it could restrict the minimum internal radius. I have the same Stanley compass plane as you and find it a pleasure to use.

 

[Rob Platt]

My record compass iron is 2mm. same as most of my other bench planes.
info for what its worth?
all the best
rob

 

[matthewwh]

I'm not sure why they are so thin but my Record 020 also has a very thin iron. I suspect Andy may have hit upon the thinking behind it.

I wouldn't attempt filing the mouth on one of these in order to fit anything thicker as there is already perilously little material around the rivetted joints. The original tungsten blade on mine is just lovely and nearly new, so no need to change it, other than to test which of our our irons would or wouldn't fit.

I did however try installing a thicker 1-3/4" low profile cap iron which has markedly reduced it's propensity to flutter at the transition from with to against the grain at the top or bottom of an arc. It wasn't doing it all the time, but enough that when I used it I was kinda waiting for it to happen, now I can concentrate on hitting the line without worrying about spoiling the work on the final pass.

 

[Phil Pascoe]

My Stanley Victor No.20 has a nice "Sweetheart" iron that is just over 2mm, it's parallel. The mouth is 4mm give or take that accurate unit of measurement, a smidgin.

 

[Woody2Shoes]

I wonder if it's thinner than otherwise might be expected because of the fact that it's tungsten steel:
- more rigid/stiff than ordinary tool steel?
- more expensive than the ordinary?

What bevel angle do people use on their compass plane blade?

Cheers, W2S

 

[D_W]

It's probably thinner literally because the engineers at stanley found that it was fine for it to be thinner. It's a plane that's never going to take a 3 hundredth thick shaving.

I had a 020 years ago, but I don't remember the era. The iron was tall and thin. Thanks to this thread, I went out and got another one :? Sunday night impulse, I guess. Good thing is, at least in the states, the 20 costs marginally less now than it did when I sold mine.

I have an old wooden one that works fine, though I'll admit that the 020 is a bit more appealing to me because it's easy to use. It wasn't quite so easy before learning to use the cap iron, though!! (at least not as easy to use it quickly with nice thick shavings as custard has shown in another thread).

As far as tungsten steel vs. water hardening vs O1, I don't think it makes much difference in how much an iron will flex - I think hardness determines that.

 

[Biliphuster]

As far as tungsten steel vs. water hardening vs O1, I don't think it makes much difference in how much an iron will flex - I think hardness determines that.

You are right in that o1 and Tungsten steel will deflect the same amount for the same load (i.e. they have the same stiffness) as they have almost the same Youngs Modulus (which will also be almost the same as pure iron).