Blade angle for a #5?

[Charles McKinley]

Hi All,

I have just started the slippery slope and am amazed by my new diamond and water stones!

What blade angle do you suggest for a #5 jack plane? As the Lee book stated the angle on it is 20 degrees. He suggest 30 to 35 degrees.

I want to use this for removing the bandsaw marks from slabs and rough lumber. The bed angle is 45 degrees.

Do I redo the entire angle at once or can I take it back a little at a time as I sharpen the iron until it is at the new angle? I have the Veritas guide and jig to help set the new bevel.

Thanks

[Michael Campbell]

Hi All,

I have just started the slippery slope and am amazed by my new diamond and water stones!

What blade angle do you suggest for a #5 jack plane? As the Lee book stated the angle on it is 20 degrees. He suggest 30 to 35 degrees.

I want to use this for removing the bandsaw marks from slabs and rough lumber. The bed angle is 45 degrees.

Do I redo the entire angle at once or can I take it back a little at a time as I sharpen the iron until it is at the new angle? I have the Veritas guide and jig to help set the new bevel.

Thanks

On a standard Bailey style #5, the blade goes bevel down, so the grind angle isn't all that critical... (is it?); the angle at which the blade contacts the wood is the bed angle, regardless of grind.

I've always done my jack planes at a 25 degree bevel angle. If I need to re-bevel a blade, I use a bench grinder with a white aluminum oxide stone for the initial bevel, then either waterstone or Scary Sharp after that.

[Bob Smalser]

"so the grind angle isn't all that critical... (is it?); the angle at which the blade contacts the wood is the bed angle, regardless of grind."

Yes, the angle is critical...draw a picture of how the combined bed and bevel angles cut the wood and you'll see.

To answer the question...for your purposes, I don't think it matters much. I believe my jacks are gound at 25 degrees and secondary-beveled to 30 degrees.....I'll measure them this afternoon and post if they are different from that.

Edited to add...."Yup."

http://pic3.picturetrail.com/VOL12/1104763/3302194/40548925.jpg

[Charles McKinley]

Thank you both for the relies.

Bob I'm looking forward to your article.

[David Klug]

Bob, thats a neat guage you have there. Where did you get it?

Dave

[Bob Smalser]

Just and old drill bit gage from General in Canada....look under machinist tools. I love machinist T-shaped depth gages as mini squares, too.

[Michael Campbell]

"so the grind angle isn't all that critical... (is it?); the angle at which the blade contacts the wood is the bed angle, regardless of grind."

Yes, the angle is critical...draw a picture of how the combined bed and bevel angles cut the wood and you'll see.

I did, and I still don't see it.

The angle at which the blade contacts the wood is the bed angle, period. The bevel angle, is on the "back" side of the blade.

Not arguing, I just don't see what you're getting at. (I'm assuming no back bevel or micro-bevel, as I don't use either, and it simplifies this discussion.)

Given the same depth of cut (and reasonably sharp blade), the only thing I can see a bevel angle affecting is how much metal is behind the shaving, which might change it's cutting characteristics, but that's not the question at hand. Or have I misread.

[Bob Smalser]

You are correct about the flat side of the blade contacting the wood at the frog angle...but can't you visualize how different bevel angles will either slice into the wood too deeply/too quickly...steep bevel...or not bite in deep enuf and the fragile edge break off...shallow bevel?

[Charles McKinley]

According to Mr. Lee,

If you go below 30 degrees you encourage blade chatter, higher than 35 degrees he says the blade dulls faster. (paraphrased)

I was asking what other people found worked well for them and the best way to change the angle on my iron.

Thanks

[Michael Campbell]

You are correct about the flat side of the blade contacting the wood at the frog angle...but can't you visualize how different bevel angles will either slice into the wood too deeply/too quickly...steep bevel...or not bite in deep enuf and the fragile edge break off...shallow bevel?

No, I can't. I guess I'll just have to use the experience of those ahead of me and trust.