Having read with great interest all the comments in the “Plane Characteristics” thread I began to wonder why most infill planes are furnished with 3/16 thick plane irons and most high end metal planes like Lie-Nielsen are furnished with .125 to .140 thick irons. Would a thicker iron in these planes improve performance? Does it have to do with the fact that the thinner irons are bedded on a iron frog in lieu of the wooden infill? Another question that’s been preying on my mind.
Ron
Replies
Ron
Interesting question. There is a bit of a fashion for thicker (up to 3/16) irons, and also heavy back-irons/chipbreakers.
There's a practical limit to thickness - to do with sharpening and having to remove increasing amounts of metal. Thinner irons sharpen quicker (but run an increased risk of heating up if ground - not that I do!).
There are cost considerations. Thinner is cheaper.
To my mind the major benefit of thicker irons is that they have greater damping characteristics - dont resonate/vibrate/distort under pressure as much as thinner irons.
Upgrading to a thicker iron will also close the mouth of a fixed-frog plane (and some planes won't accept thicker irons without filing open the mouth).
My two cents worth!
Malcolm
.125" is okay and 3/16" is pretty good, but for the ultimate check this out: http://www.leevalley.com/wood/page.aspx?c=2&p=49588&cat=1,41182
Is that the ultimate or overkill?Ron
It's a joke, right?
A few days early for April 1st!?
Malcolmhttp://www.macpherson.co.nz
Hit the "Click here for more information" link for the answer.
David C.
I think that's from last year? I remember seeing it somewhere before.Handplane Central
I believe that was their April Fools from two years ago as last year was a personal favorite, the "Dodecagauge." Hope they're doing it again for this year.
Ahh, the years seem to flow into one another the older you get :)Thanks for the clarification.Handplane Central
Rick, what is this gauge? (I know that dodeca means "twelve" in Greek)-but?Philip Marcou
Here's the gauge in question: http://www.leevalley.com/wood/page.aspx?c=2&p=51633&cat=1,42936 I could have used this myself today as I had some rather complex mortises and tenons to lay out.
I'd like to make myself a set of wooden planes, and I'm torn about what to do for the blades. I could order Hock blades (easy), or try to make my own (the hard way -- the type of choice I often make and almost as often regret). I have some leaf springs I pulled at the junk yard for this purpose. Leaf springs are made from high carbon steel. The ones I have are 1/4 inch thick -- ideal for plane blades I think.
Now, I'm no blacksmith, but I have been reading up on basic blacksmithing techniques, annealing, hardening, tempering, etc. I'm wondering whether making my own blades (good blades that will take and hold an edge) is within my abilities as a complete rookie blacksmith.
The sensible practical side of me says go buy the blades (though it is not an insignificant expense for a set of 6-8 planes). The steel is probably hardened and tempered better than I can do, and I'll save myself a lot of time. But, 1/4 inch thick blades would be better I'm sure, and it would be really satisfying and fun if I could make my own.
Personally I would buy the Hock irons. You could buy the 3/16 thick irons that they sell for Infill type planes and also get the chipbreaker. You could pursue making your own but if they don't turn out you'll have a lot of time invested in blades that you can't use. With the Hock irons you could already be making shavings. I recently made a wooden mockup of a plane that I intend to make in metal. I put the 3/16 Hock iron in it just to prove it out and I was amazed at how well it worked. Had I been intending to make a wooden plane I would of course have had a body with more mass and it would have probably worked even better.I'm assuming that you will have to have the leaf spring material surface ground and if that's not something that you can do in your own shop that may cost as much as the Hock irons.Ron
Well, I went ahead and decided to do it the hard way (will I ever learn?). I did some research and found out that the 80s vintage leaf spring steel I have is most likely 5160 -- great for knives and axes, but can't be hardened quite enough for a superior plane iron. 1095 spring steel is the way to go, so I ordered some 1/4" thick by 3' long blanks in 1-1/2", 2", and 2-1/2" widths. All I will have to do is anneal/normalize it (if it isn't already), shape the bevel, then harden and temper it. I'm sure it will take some experimentation to get it right, but assuming I don't waste too much of the stock in the learning process, I'll have enough to make a lifetime supply of irons for just over the cost of one Hock blade.
But I may buy one Hock blade just to have a basis of comparison.
I've seen wooden planes without the chip breaker, so that's what I'm going to try. I'll be aiming for just a few thousandths gap between the throat and the blade. I'm actually thinking of using 3/16" flat mild steel for the sole. I figure it will stay flat better than a wood sole, and I'll be able to better fine tune the gap
I'll try and post some pics of my progress. Any suggestions before I start would be more than welcome.
Thanks.
I think that the steel sole is a good idea. With the bed side of the opening in the sole cut and filed at a corresponding angle with the infill side where the iron will be bedded you will get great support on the back side of the iron, much superior than what can be achieved with wood. In fact you may want to extend the benefits of this by adding a metal ramp similar to the ones used on infill smoothers to increase the area where the iron will be supported by metal. The steel sole will also give you some much needed mass that is hard to achieve with a wood only body. Fitted with a tight throat this should make a quite nice plane. I'd surely be interested in seeing some pics and hearing about how a plane of this configuration works.Ron
Since posting this thread I have done a good bit of reading about planes and have especially paid close attention to what is written concerning iron thickness. It seems that the benefits of a thicker iron have a lot to do with how well the iron is supported. A wooden bodied plane would most likely not have the rigid support that a metal plane would provide so it would most likely benefit the most from the thicker iron. A metal plane that provides good solid support to the back of the iron all the way down to the bevel would most likely not benefit much from the upgrade from say a .125 to .187 iron. There may be some benefits obtained from the thicker iron in situations where the frog is adjusted forward in a metal plane to tighten the throat and therefore leaving a small upsupported space on the back of the iron just up from the bevel. I however have not actually put this to a practical test so I couldn't testify to first hand knowledge. I personally like the thicker irons because of the increase in the size of the bearing surface on the shapening platens. It makes it easier for me to achieve accurate honing while free handing the sharpening process.Ron
Update:
After spending two days building and trouble shooting my forge, I've got it running great. Now I'm experimenting on two blades that I made -- one for the wooden bodied, steel soled plane, and one for a Record #4 smoother that I'm modifying to accomodate the thick single iron. My first attempt at hardening was not entirely successful. I used an oil quench which may not cool the 1/4" thick blade quickly enough. I got the cutting edge very hard, but the rest of the blade can still be filed. I'll try water next -- hopefully it won't crack.
I've been taking pics, and I'll try to do a post documenting the whole process soon.
I'm quite anxious to see it.Ron
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