honing jig projection distance for 13 degree

[luckduck32167]

whats the projection distance in mm if i want to get 13 degrees? that is from the front of the jig to the cutting edge of the blade.

[stevemc32]

I'll have a go.

It depends on the height of your honing jig.

So measure the height of your jig perpendicular to the blade mounting surface and then divide that by Tan 13 degrees ( =0.231 ) to get your total blade projection from the point on the jig at which the height was measured.

To get the blade projection from the front of the jig, you'll have to minus off the distance from the measurement point to the front of your jig.

Makes perfect sense to me but not sure if I've explained it too well.

Maybe a diagram will help.

[luckduck32167]

I'll have a go.

It depends on the height of your honing jig.

So measure the height of your jig perpendicular to the blade mounting surface and then divide that by Tan 13 degrees ( =0.231 ) to get your total blade projection from the point on the jig at which the height was measured.

To get the blade projection from the front of the jig, you'll have to minus off the distance from the measurement point to the front of your jig.

Makes perfect sense to me but not sure if I've explained it too well.

Maybe a diagram will help.

please draw pic

[seanz]

Cheat.

Take a new one (if available) of whatever it is that you're sharpening and rest the bevel on the grinding wheel and adjust the jig to suit.

I have a brand new never used Stanley plane blade for this purpose when doing that type of blade.

What are you grinding/sharpening?

[luckduck32167]

Cheat.

Take a new one (if available) of whatever it is that you're sharpening and rest the bevel on the grinding wheel and adjust the jig to suit.

I have a brand new never used Stanley plane blade for this purpose when doing that type of blade.

What are you grinding/sharpening?

im sharpening a stanley 60 1/2 low angle block plane blade

[stevemc32]

Ok.

Measure the distance in Red and divide it by 0.231 to get the calculated distance. Then take off the distance from the top of the Red line to the front of your jig for the projection distance.

Attachment 154316

There is a bit of inaccuracy introduced when you tilt the jig over to 13 degrees which is dependent on the radius of your honing jig wheel but I suspect it really won't affect your result noticably.

Hope this helps.

[stevemc32]

Cheating sounds good if that option is available, otherwise just line it up with a protractor if you can find one.

I don't know how long a 60 1/2 blade is but the calculations indicate that it will need to project about 130mm if your jig is 30mm tall. Might be a stretch for it.

[luckduck32167]

ye that helped, thx

[Mr Brush]

Just curious why you want such a shallow bevel angle - 25° is standard for that blade; bedded at 12° bevel up gives a 37° cutting angle. This works fine even for end grain paring.

I would have thought any cutting edge with a 13° bevel wouldn't be very durable?

[luckduck32167]

Ok.

Measure the distance in Red and divide it by 0.231 to get the calculated distance. Then take off the distance from the top of the Red line to the front of your jig for the projection distance.

Attachment 154316

There is a bit of inaccuracy introduced when you tilt the jig over to 13 degrees which is dependent on the radius of your honing jig wheel but I suspect it really won't affect your result noticably.

Hope this helps.

Just curious why you want such a shallow bevel angle - 25° is standard for that blade; bedded at 12° bevel up gives a 37° cutting angle. This works fine even for end grain paring.

I would have thought any cutting edge with a 13° bevel wouldn't be very durable?

now that u mentioned it, the shallower the angle the less metal particle there is therefore its alot less durable. So yes i think ur right.

[Mr Brush]

Plus you'll have to remove an awful lot of metal to get from 25° down to 13° !

Seriously, I've never heard of a plane iron being sharpened at such a shallow angle. Hardwood end grain will wreck such a fine cutting edge in no time.

[luckduck32167]

Plus you'll have to remove an awful lot of metal to get from 25° down to 13° !

Seriously, I've never heard of a plane iron being sharpened at such a shallow angle. Hardwood end grain will wreck such a fine cutting edge in no time.

ye that is alot of metal and ill b like when i c how short my blade become. To my knowledge, hardwood requires a steeper angle bcuz it wants that engagement from the blade, softwood not as much. I think my current secondary bevel angle is close to being aight.

[derekcohen]

Deneb will show you how to do this here: [ame=http://www.youtube.com/watch?v=yzeAsX-09o4&feature=related]YouTube - Sharpening Part 1: Plane Irons[/ame]

Regards from Perth

Derek