Tweak your cap iron

**Thumbthumper** · 27th April 2009, 09:19 PM

I wasn't happy with the way my Stanley 4 1/2 was performing when I closed up the mouth to smooth gnarley figured woods. It seemed to clog with each stroke. Even an old toothbrush couldn't clear the shavings. I'd have to undo the lever cap, and pull out the iron to remove the shavings, and back the frog off a bit to get it to work

. Closer inspection on some work showed the beginnings of tearout when I opened the mouth.
I wanted to achieve that hairline mouth and super fine cuts.
I'm fairly careful when I initially fettle my planes... so I thought.

Surgically sharp blade...check
Flat base...check
Clean mouth with no dags, and the right angle...check
Cap iron sitting properly across the iron...check

After a bit of online research, I stumbled across this video
http://woodtreks.com/how-to-use-a-hand-plane/21/

Special attention was paid to fettling the cap iron. Now I was always careful to hone the end that sits across the iron, but when I looked at the cap from the side, it almost had a bevel on the front edge. It wasn't a graceful curve.
The author of the video states that the edge should be sharp enough to cut.
So I took to the cap with a fine file and removed the bump and refined the curve. Then down through the grades with wet and dry till I achieved a mirror shine and a sharp edge.

I put the plane back together, and advanced the frog to the super fine mouth position.
I held my breath, put the plane to some figured cedar, and advanced the iron bit by bit (still holding my breath

).

Wow !

Fluffy tissue-like shavings shot almost vertically out of the plane. My 4 1/2 now works better than it ever has.

I will no longer neglect my cap irons.

Sorry if this is old news for most, but it was a revelation for me
(and sorry for the long winded post

)

Regards all,
Stu

**Groggy** · 27th April 2009, 10:12 PM

Two things I disagree with in the video. firstly, I would not crank down the frog as tight as possible, I'd be worried about stripping a screw. Tight yes, tight as possible - no.

The second issue is with the flattening/sharpening of the cap iron. If the cap iron is flattened on a stone in the manner described then, when pressure is applied to the cap iron, the leading edge will lift free of the blade and catch shavings underneath. When flattening it is better to have the back of the cap iron slightly below the stone to create a higher angle. In this way, when applying pressure to the cap iron the leading edge remains in firm contact with the blade and there are no openings for shavings to get under.

I'm sure others will join the discussion.

**bluegum30** · 27th April 2009, 10:16 PM

It's never long winded to explain something in detail, because when you explain it like you did its like looking over your shoulder and understanding the problem as it happened and how you corrected it.

Lloyd

**Thumbthumper** · 27th April 2009, 10:22 PM

Originally Posted by Groggy

Two things I disagree with in the video. firstly, I would not crank down the frog as tight as possible, I'd be worried about stripping a screw. Tight yes, tight as possible - no.

Absolutely agree. Stripping a screw, or cracking the cast iron.

....it is better to have the back of the cap iron slightly below the stone to create a higher angle. In this way, when applying pressure to the cap iron the leading edge remains in firm contact with the blade and there are no openings for shavings to get under.

Agree again. This is the way I've always done it. I use a block next to my stone to ensure the correct angle.

The main thing I took away from this video was the sharp cap iron edge. It definitely improved performance for me.

I must admit, I did skim over a lot of this video (I was looking for a solution to my particular problem).

**Groggy** · 27th April 2009, 11:44 PM

I should have also said it is a good video, which it is. I haven't seen many that get it all right and couldn't do better myself. I feel it is too easy to criticise at times, but on occasion it helps to clarify a point or two. There are some other very good videos on that site, definitely worth a look.

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