Required clearance angle on plane blade

[william sympson]

I didn't find a thread on the subject. I am intrigued somewhat by a 40 degree bed angle on a bevel down plane and using the cap iron as needed for tear out control. Seems like it would be a great option for good performance on both end and face grain. I sharpen free hand so I can get close to an angle but not exact, so I would like to hear from the more experienced on the required/preferred/practical clearance angle for a bevel down plane blade.

[Steve Voigt]

You should be fine at 40° in terms of clearance angle. The minimum clearance you'll need depends on a lot of factors (depth of cut, species, etc) and can vary, but will typically be between 10° (at a bare minimum) and 15°. There is good reason Stanley never went below 12° on their BU planes. But if you have 10° - 12° clearance, your iron will be beveled at 28° - 30°, and most irons will hold up in that range, even on end grain. You are more likely to have problems if you go for really low angles, say 37° or below. I speak from bitter experience. (head slap)

[Warren Mickley]

I did experiments with clearance angles in 1976. I found that with 8 degrees I was confident that there were clearance problems and with 11 or 12 degrees I was confident there were not. There is probably a slight difference in threshold with different woods.

I have used the same five bench planes for over thirty years; their beds are 42, 43, 43, 45, 45. I can see a very slight difference in quality between 42 and 45 on end grain especially. I would say that the closer you get to 39 degrees the less leeway you have for inaccuracy in your sharpening. If you can see a slight rounding of your bevel, you need a little more clearance to account for that. Also if you raise raise the iron up on your finest stone, so that you are only sharpening the tip, you should probably add 3-5 degrees to the clearance.

[Jim Koepke]

+1 on what Steve said.

To my knowledge there are only a few specialty planes that bed at less than 12°. Side rabbet planes from Lie-Nielsen have blades bedded at 8° according to the use information page on their site.

I sharpen free hand so I can get close to an angle but not exact, so I would like to hear from the more experienced on the required/preferred/practical clearance angle for a bevel down plane blade.

This would be a good reason to use a 25° bevel. Having 15° of clearance would leave room for either a secondary bevel or angle creep which can happen with free hand sharpening.

jtk

[Derek Cohen]

It is quite likely that planing softwood requires a slightly higher clearance angle than hardwood, however around 10 degrees should cover both situations well enough.

In a recent experiment with the new LV custom jointer it was possible to compare a few configurations that have been topics on this forum for a while. In particular I was interested in the performance of a BD plane with a 40 degree frog and using the chip breaker vs a BU plane with a 52 degree cutting angle (12 degree bed and 40 degree bevel). Associated with this was whether one could determine a difference in the quality of the surface after plane with each set up.

The wood used was a piece of European Oak (similar to English Oak but a little less dense in my experience). This piece had some sections of reversing grain and a small knot.

The other issue was that the BD blade was honed on a 30 degree hollow grind, leaving 10 degrees of clearance. Would this be sufficient?

BD - Using the 40 degree blade without the chip breaker: tearout in all the expected spots.

BD - Using the 40 degree blade with the chip breaker: Good finish. No tearout.

BU - Using the 52 degree blade: Good finish. No tearout.

Was there a difference in quality of finish between the 40 degree and 52 degree set ups? Looking for shine with the light reflecting on the wood I would argue for a slight preference for the 40 degree plane.

Then I added a single coat of Ardvos oil (my preference now since building The Chair) ...



I asked both my 21-year old son and my wife to tell me which they thought was the smoothest and clearest surface of the two choices on offer - in other words a blind test. Neither could tell the difference. When pushed to make a choice, one choice "A" and the other chose "B". It seems oil is a great leveller (on this occasion, at least).

Bottom line, however - 10 degrees of clearance worked just fine in this situation.

Regards from Perth

Derek

[william sympson]

Gentlemen, I really appreciate the insights and experience/wisdom.

Steve, I often learn by the brute force and awkwardness method (read mistakes) and then do the head slap- it's nice to know I'm in good company - great point on the bedding angles, i didn't stop to think about it... a good part of the answer to my question is there.

Warren, part of what has attracted me to the 40 bed angle, is a shoulder plane I have that is bedded at 15 degrees - I notice better looking end grain and ribbon shavings with a 25 degree flat bevel on the iron. I decided to raise it to around 30 degrees to save time and see if the occasional minor chipping would stop (A2) and noticed a visual difference in the surface quality, no more ribbons, and more effort to push it. You're correct on the minor rounding of the bevel when I sharpen.

Derek, your test is one that I couldn't do but found myself thinking about - great stuff. How does it work on a shooting board with the reduced size sidewalls? I look forward to one of your thorough reviews on that plane...that's the one I'm thinking about getting.

I am probably an oddball, but I use my #7 on a shooting board, large end grain surfaces, and smoothing. I've gotten used to the size and find it comfortable/easy to use in all these situations...so that 40 degree bed and cap iron option is appealing to me. Looks like I'll have to pay more attention to sharpening angles if i go the 40 degree bed route.

R/
William

[Winton Applegate]

angle creep which can happen with free hand sharpening.

Sounds creepy !

Japanese wood body planes are often less than 45 bed bevel down and work fine. But then the bimetalic blades (to apply a modern term to tools that are a thousand years old) . . . are self jigging while sharpening.

Ceeps the creep cowering in the creek.

[Winton Applegate]

have to pay more attention to sharpening angles

angle creep will get you

Ahhhhhhhhhhhhhhh
it is good to hear some faint echoes from my passionate pompous posts of the past.

[william sympson]

Winton, am I understanding you correctly...it seems as though you're implying that going commando is the way of the future for you?

[Winton Applegate]

going commando

Ha, ha,
No . . . just the opposite, for this thread anyway, . . .
I am advocating for control of the tool . . . sword . . . I mean blade.
Tie that loose cannon down to a jig
to prevent the creep.

PS:
I know this is a stupid place to ask but can some body tell me what happened to my thread titled : For Frank Fans.
?
Seems to have been removed.
I must have violated a rule or sumpin.
Or maybe it is here and I am blind.

[Jim Koepke]

PS:
I know this is a stupid place to ask but can some body tell me what happened to my thread titled : For Frank Fans.
?
Seems to have been removed.
I must have violated a rule or sumpin.
Or maybe it is here and I am blind.

Did you try the search box in the upper right hand corner? (at least that is where it shows up in my browser)

Picture 1.png

Type in > frank fan applegate < and you will find it after you either press enter or click on the magnifying glass icon.

jtk