Bolster fitting with Lauri Leuku blade

[Drumgerry]

Hi all

I wonder if I can ask a bit of advice. I have a Lauri Leuku blade as shown below and on contemplation of starting a bolster for it I came across something I haven't before in my short knifemaking career so far. I noticed that the tang has been partially ground away so that it's thinner at the bottom just where I need a gap-free join ie at the start of the blade. So if I was going to leave the tang as it is I'd need to cut the bolster to get over the thicker part of the tang which would then leave a gap with the tang being thinner further up. So am I just going to have to grind the tang to even it up (never having ground much in the way of metal before)? Or is there something I'm missing which would get the job done?

http://i30.photobucket.com/albums/c321/drumgerry/laurileuku.jpg

Cheers

Gerry

[Stew]

That's the reason why I won't buy a lauri again. Grinding the tang is not easy if you don't have a suitable power tool.

You could try casting a bolster out of pewter (http://www.britishblades.com/forums/showthread.php?t=7672).

[Drumgerry]

Well I do have a belt sander and I can mount a drum sander in my drill press. Is grinding my only option?

Gerry

[Drumgerry]

Oh and I don't think I've got time to master pewter-casting - I'm trying to get this knife and sheath making mullarkey as good as I can get it just now!!

Gerry

[Stew]

I can't think of any other unless you're prepared to do a mortise tang?

[ElThomsono]

You can get a cheap angle grinder for £5, would that be suitable?

[Drumgerry]

Please forgive my ignorance Stew but what's a mortise tang?

Cheers

Gerry

[Stew]

Please forgive my ignorance Stew but what's a mortise tang?

Cheers

Gerry

It's basically 2 blocks sandwhcihed around the tang.

ZDP-189 did a good tutorial with a spacer in between the 2 blocks.

Hidden Tang (http://www.britishblades.com/home/articles.php?action=show&showarticle=23)

JM has a tutorial for a lauri over at OMF where he mortise tangs it and a bolster. (He grinds the tang down)

Tanga knife (http://forums.outdoors-magazine.com/viewtopic.php?t=486)

[Judas]

Avoid grinding the tang if you can. I use a knife-edge needle file– the ones with a narrow wedge profile for the bolsters on blades with an edge grind that carries onto the tang. Like this:

http://shorinternational.com/images/ImagesF/filesknifecrossection.gif
http://shorinternational.com/images/Images31/31551.gif

A few minutes of filing can make a perfect fit, you won't weaken the tang/bolster junction, and the strongest part of the blade (right before the bolster) will be avaialble for cutting. :)

[Stew]

The thing is Judas, that lauri blades have a wider tang at the end than at the bolster area.

If you look at the picture, the silver area on the tang has been ground back - that's how it comes.

[Hepotec]

I have recently had the same problem. I ground down the tang to a uniform profile using a bench grinder. An angle grinder might be a little aggressive unless used very carefully.
However, you might also want to try using a different bolster. For a smaller Lauri scandi I bought two bolsters. One wouldn't go on and I considered grinding the tang. Then I tried the other bolster and it slid right on as if it had been made for the job.

For future reference the Kankaanpaa Leuku blade blank doesn't have this problem and is an excellent buy.

[CPShines]

I used a Lauri blade for my first and had the same problem. I tempered the tang with a blowtorch, and then used a 12" second cut file to file it down.

Took about an hour to file the tang down, and the big gouges in it meant that the epoxy had something to grab onto when I bonded the handle onto it.

If I were doing it again I'd use a b*stard cut, but for now I'm buying blades with uniform tangs and ricassos precisely to avoid this problem.

[Drumgerry]

My plan is to make an antler or wooden bolster for the blade - not too keen on the brass jobbies which are nominally supposed to fit the specific blade but seem to be miles out most of the time.

A quick pass or two on the belt sander might be the way I go with this one to even things up or I might hand file depending on my mood at the time!!

It does seem bl***y stupid that they haven't just kept the grind going right up to the end of the tang. And I have made a Leuku from a Kankanpaa blade without this problem.

Thanks for the great links Stew and to everyone else for their help.

Cheers

Gerry

[Judas]

The thing is Judas, that lauri blades have a wider tang at the end than at the bolster area.

If you look at the picture, the silver area on the tang has been ground back - that's how it comes.

Ah yes, sorry, I misinterpreted the problem. Thanks.

[dBu24]

I 'd NOT rush to grind that tang down: you will weaken it and might break off in use.

Unless you plan to never use that knife.


First go and measure the cross section of the tang, cut the slot to those dimensions and you might discover that miracously, it fits nicely! The thick part is narrow enough to fit thru that slot. You wil see yourself how it fits into place.

Good luck


David

[Drumgerry]

Right I've measured with my micrometer - the tang at the blade join is 3.2mm tapering to 1.96mm. Where the grind finishes the tang is a pretty uniform 3.2mm from top to bottom. So if I cut the slot a uniform 3.2mm and slide the bolster on I'll have an unsightly gap of 1.24mm - not too desirable I'm sure you'll agree!! If I cut it to 3.2mm tapering to 1.96mm there's no way the bolster will slide on at all. I don't think that there can be a miraculous fit in these circumstances!

It sounds like plenty of people are carefully filing/grinding their tangs to even them up and the resultant knives I am sure must still be strong enough to be fully useable.

Of course there is that mortised tang idea!! But knowing me I'd mess it up!

Cheers

Gerry

[Drumgerry]

I'm sorry David but I've thought a bit more carefully about what you've said and I think you might be right!! The slot I need for a gap free fit for the bolster has a section of about 18mm of 3.2mm wide. The remaining bit (about 7-8mm) is where the taper to 1.96mm takes place. But that 18mm of 3.2mm width is more than enough to get over the first bit of the tang.

Man I couldn't see the wood for the trees and the solution was staring me in the face all the time!!

Thanks for your help.

Cheers

Gerry

[dBu24]

he he he... I knew you'd be back after seing the truth:rolleyes:

Unfortunately (or not) I don't have at hand an unassembled Lauri blade to follow your carefull measurements, but I see you found the solution and what I meant.

I had once that very same problem, but then it occured to me that those folks cannot be THAT dumb and there MUST be a right way to put that thing together without ruining the blade with the sanding belt or an acetylene torch

It sure is easier to fix a blade with a proper rectangle at the base , but with the Lauri design , if well done, it looks neat.

All the best

David

[CPShines]

The other way I've heard it done is this, if you're using a brass or nickel silver bolster. Make the slot in the bolster wide enough to get it over the tang and pushed up against the blade, then carefully squeeze it with a vice or a pair of pliers to squash the slot until it fits neatly around the blade.