Plane Iron Grind Angle for BDs

[Anonymous]

In theory at least, there's nothing to even put a secondary bevel on!

In practice there is and it has been working very well for me for a very long time...........

 

[Anonymous]

Here you are bugbear - this one is ground at around 26.5 degrees it turns out (I don't check too carefully, as I don't really care if it is a couple of degrees out on the primary bevel grind)

I grind all blades on the same grindstone with the guide set to the same angle (not adjusted it for ages)

 

[bugbear]

Here you are bugbear - this one is ground at around 26.5 degrees it turns out (I don't check too carefully, as I don't really care if it is a couple of degrees out on the primary bevel grind)

Yep - that's measuring the chord, which (as discussed) is OK as long as the wheel is "reasonably" large.

BugBear

 

[bugbear]

In theory at least, there's nothing to even put a secondary bevel on!

In practice there is and it has been working very well for me for a very long time...........

My comment on theory applies to the limiting case of a small wheel (as illustrated).

BugBear

 

[Wanlock Dod]

Yep - that's measuring the chord, which (as discussed) is OK as long as the wheel is "reasonably" large.

So Bugbear, are you going to reveal how big "reasonably large" needs to be before this isn't an issue any more?

Cheers,

Dod

 

[Anonymous]

Yep - that's measuring the chord, which (as discussed) is OK as long as the wheel is "reasonably" large.

So Bugbear, are you going to reveal how big "reasonably large" needs to be before this isn't an issue any more?

Cheers,

Dod

Dod

My wheel started out at 150mm and is probably quite a bit smaller by now after 4 years occasional use, and that works fine as shown in the photo above - maybe that defines "reasonably large"?

 

[Wanlock Dod]

Tony,

I usually aim for a slightly steeper angle, hoping that this will accomodate the reduced angle at the tip, although in practice I've little confidence in it making a great deal of patience. I did wonder if anybody cared stringly enough to calculate that the minimum radius of "reasonably large" is actually 137.2^14 thousandths of an inch (and yes I'm sure that would be the unit of choice for the radius).

Cheers,

Dod

 

[bugbear]

Yep - that's measuring the chord, which (as discussed) is OK as long as the wheel is "reasonably" large.

So Bugbear, are you going to reveal how big "reasonably large" needs to be before this isn't an issue any more?

Cheers,

Dod

If I work it out, I'll reveal it!

BugBear

 

[David C]

Rod,

I am not aware of getting Chatter. If I was I would not recommend this slightly lower than UK convention (25 deg ) grind angle.

The advantage in my system is more honings between regrinds. I reckon to get at least 7, using an eclipse type side clamping honing guide.

I would suspect that Jim Reed has ground your blade for freehand honing.

best wishes,
David

 

[Harbo]

Thanks for the comments everybody - I tried not to get dragged into the hollow ground debate but most of the books I have read seem to recommend it as it allows a secondary bevel to be formed without taking off too much steel (that's after a 25 ish primary bevel has been formed?). The argument against it was that a straight bevel in theory offers more support and therefore reduces the risk of chatter? But DavidC teaches a 22.5 bevel and has confirmed no apparent chatter.
I generally use a Tormek for grinding which starts off with a 10" wheel so I reckon that must be reasonably large?

One thing I experienced today (and it was confirmed on Alf's Blog site) was that the bevel angle on Plough Cutters (Record 43's) should be 35 degrees. This in practice equates to the bevel being parallel to the sole and therefore offers maximum support.
I tried out a cutter which had been ground with a 25 degree bevel and a tiny piece of wood became jammed between the iron and the frog - reducing the performance considerably - it was quickly reground to 35!

Rod

 

[Paul Chapman]

One thing I experienced today (and it was confirmed on Alf's Blog site) was that the bevel angle on Plough Cutters (Record 43's) should be 35 degrees. This in practice equates to the bevel being parallel to the sole and therefore offers maximum support.
I tried out a cutter which had been ground with a 25 degree bevel and a tiny piece of wood became jammed between the iron and the frog - reducing the performance considerably - it was quickly reground to 35!

The same with combination plane blades. It's best to keep to 35 degrees and not hone a secondary bevel. That way it helps you to not lose the shape of the shaped part of the blade.

Cheers :wink:

Paul

 

[ydb1md]

One thing I experienced today (and it was confirmed on Alf's Blog site) was that the bevel angle on Plough Cutters (Record 43's) should be 35 degrees. (snip)
I tried out a cutter which had been ground with a 25 degree bevel and a tiny piece of wood became jammed between the iron and the frog - reducing the performance considerably - it was quickly reground to 35!

Rod

Are you saying that a piece of wood became jammed between the frog and cutter on your Record 43? I'm pretty sure that my Record 043's, and my 044's, don't have a frog in the lot of them. :roll: :wink:

regards,
Dave

 

[Harbo]

How about a toad? :wink:

Frog or bed - the sloping bit that the iron beds on.
What do you call it?

Rod

 

[ydb1md]

How about a toad? :wink:

Frog or bed - the sloping bit that the iron beds on.
What do you call it?

Rod

The bed. :wink: