Cosman Blade

[Pat Meeuwissen]

Guys, here is a pic of my Frankenplane. Its a Bailey #5 with a Cosman blade which I finished sharpening and honing. Now have get it to fit this plane. I found a video by Rob Cosman that says you have to file the throat to get a proper fit as the blade and back iron are so much thicker actually over twice as thick as the original ones. In the video he never says how much to file that heard or saw.
Has anyone done this type of retro fit and is your throat opening beyond .260 inches? In the pic of the throat and blade the back of the blade is bottomed against the sole of the unit and the blade is still not projecting. I have a small amount that I can still move the frog forward and try to bring the blade thru again but it would most likely hit the front edge. Just want to ask b4 I take away too much material. Any thoughts advice welcome.

[Greg Wease]

I haven't done it myself but have a friend who had to increase the opening by 1/8" on a Bailey #5 before his blade projected. That convinced me I didn't need a Cosman (IBC) blade.

[Pat Meeuwissen]

Greg is there any chance your friend has a set of calipers and could give me an idea of how big it should be?

[Mike Brady]

Personally, I would pass on any product that required that much modification of a tool. Hock and Lie-Nielsen both make Stanley replacement blades that are direct fits, without modification. I found them to offer significant improvements in planing performance and edge retention. The Hock blades are easier to hone. The Cosman products promise a lot and cost you a lot, but much of their performance comes from the hand and eye of Mr. Cosman. An example: The plane irons that cost a premium because they were personally honed by him. If he will drop by weekly to refresh those edges, it might work out to be a fair deal. Otherwise you end up with a dull blade that you ​will have to hone yourself.

[Jim Koepke]

Howdy Pat,

Your pictures didn't come through.

As far as setting the frog is concerned, it should be set forward so the bed of the frog and the back of the mouth are aligned.

If the mouth needs to be filed, only enough to allow shavings to pass needs to be removed.

jtk

[Pat Meeuwissen]

Well after thinking for 2 hours that the blade was bottoming out on the shoe of the frog, it turns out it s hitting the cap iron retention screw and won't allow it to protrude far enough even with the frog beyond the base of the throat. Will be on the phone to Mr. Cosman REALLY SOON. This is just not right. Like Mike said the amount of work to fit a new blade (which by the way in his YouTube channel videos says it works) is just ridiculous. Now to solve this I would have to grind the hole in the blade and cap iron into an oval to allow it to pass further forward. I don't own machining equipment to work on tool steel.

INFO: I spoke to Rob and it turns out that they make the blade in 2 different configuration, actually the chip breaker. One came with a round hole and one came with an oval version. He said that there were many variations of Stanley #5 and some worked with round holes others did not.

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[Frederick Skelly]

Personally, I would pass on any product that required that much modification of a tool. Hock and Lie-Nielsen both make Stanley replacement blades that are direct fits.....

I agree with Mike. Suggest you return the iron if possible. LV also makesca very nice replacement blade and chip iron. Put those in my own #5 restoration and they work lovely.

[Derek Cohen]

Hi Pat

There are a couple of illogicalities here.

Firstly, a #5 Bailey is generally used as a jack plane, which means that it is a coarse tool. This involves a strongly cambered blade (typically around 8" radius) and a wide open mouth. So, opening the mouth should not be an issue - it needs to be wide enough for thick shavings.

Secondly, the blade is totally overkill for such a plane. It is a expensive blade that one would consider for a smoother, rather than a muck-about coarse plane. I think that a thicker-than-Stanley blade is better, but there are others to choose from.

Thirdly, the blade was designed before the chipbreaker came back into fashion as a means of controlling tearout. Should you choose to use the #5 as a smoother (in my opinion it is too long for this task), then you would need to open the mouth wider anyway to allow shavings to pass by a mouth blocked by the chipbreaker.

Personally, I would find a nice Stanley #4 and put this blade in that. Both the #4 and #5 are so cheap that you could screw them up and find another. It is possible that you could finish with a magnificent #4 (with the Cosman blade), and a fantastic #5 (with a LV or Hock blade).

Regards from Perth

Derek

[bridger berdel]

Over thick blades are just more steel to grind away when sharpening. I'm sure cosman's blades are quality steel, but the thickness is totally unnecessary. The Bailey pattern plane was designed for thin blades, have worked perfectly with thin blades for 150 years and will continue to work perfectly for far longer than you will be working wood.

[ken hatch]

Over thick blades are just more steel to grind away when sharpening. I'm sure cosman's blades are quality steel, but the thickness is totally unnecessary. The Bailey pattern plane was designed for thin blades, have worked perfectly with thin blades for 150 years and will continue to work perfectly for far longer than you will be working wood.


That's known as cutting to the chase :).

ken

[Chuck Hart]

For all of you that think this is not a good idea I did install a Cosman blade and chipbreaker in a no. 6 that I own. Yes I did have to modify the mouth of the plane to get the blade to work but after filing and fitting the blade I have a awesome heavy Stanley 6 that cuts .001 shavings and works much better than it did before I swapped out blades. I like a heavier plane. I am glad I made the conversion and think that if you need a heavier iron in a Stanley plane it is a reasonable conversion. Not hard to do at all.

[david charlesworth]

Pat,

I put an IBC Cosman blade and C/B in an old no 5 and wrote about it in F&C. My memory says about 1 mm was filed from the front edge of the throat. Final width about 15/64".

This filing work is easy, with a little marking out and care!

I have almost all my no 5 & 5 1/2 planes tuned up as smoothers because I have planing machinery in my shop. I am generally just refining or perfecting the machine results.

I think you will like your plane a lot.

David Charlesworth

[Mike Holbrook]

Interesting thread. Derek, as is always the case, makes an excellent suggestion. Then Mr. Charlesworth, obviously also a very accomplished woodworker, approaches the topic from almost the direct opposite position. So much depends on the environment we work in and the tools, particularly any machines, we may use. I happen to have a small lunchbox planner, I will admit, so maybe I am in the middle somewhere. I am glad I have a Stanley #5 with a large radius in the blade for making the tapered legs for Windsor Chairs and Tables.... If I had a jointer (machine), but I don't and do not want one.

I use green wood tools on white oak a good amount. When that oak dries though I may swap over to hand planes, particularly ones with radiused blades. I am now thinking that I might leave a #5 type plane with less/no radius for working tougher drier wood. Although I have a Veritas BUS smoother so I have a good heavy smoother for tough grain. So much depends on the specific work at hand.

[John Gornall]

One of the best discussions of handtool understanding and with few posters and few words. Too often one "side" takes over and a different position is crushed when actually there are numerous positions that could be discussed and expanded. So much great understanding available here when it flows. Thank you.

[Tom M King]

You could camber the Cosman iron just enough to use as a smoother, and put a Jack camber on the stock iron. The wider mouth won't hurt you a bit with the big cambered iron, and you might not even have to move the frog. I'm not sure if this would work, but might be worth a try. The reason I have so many planes is that I don't like having to spend time switching things around. Once I have one set for one purpose, all I want to do is sharpen the iron when it needs it.

[Jim Koepke]

... The reason I have so many planes is that I don't like having to spend time switching things around. Once I have one set for one purpose, all I want to do is sharpen the iron when it needs it.

A big +1 on that!

jtk

[bridger berdel]

I have a 5-1/2 (early version) that I fitted with a thick tapered cast steel iron from a woodie. it was a lot of work to make it functional, but it now behaves like a panel plane- basically a monster smoother capable of taking a big bite.

I filed as much of the mouth as I could at the back of the mouth, moving the frog back as far as fettling allowed before filing the front of the mouth.