To groove or not?

[zuludog]

I've been watching Nigel Armitage's review of Craftool Pro stitching chisels. He makes the comment that we shouldn't make stitching grooves so much as -

They weaken the leather; and as the stitching is set in a channel that restricts the sideways expansion of the stitching so that it is less able to develop the typical zigzag pattern

He just uses a line made with dividers, and then goes on to say that when the stitching is flattened and has time to settle as the item is used, there is not much of the stitching protruding above the surface of the leather anyway

Interesting; any comments?

I make mostly knife sheaths and I have always used a stitching groove, but I think that for the next couple I might just make a line with an edge creaser

[bikermutt07]

He is a member of a master's guild, so I listen to his opinion.

When I first started I was making a groove. But I was also using a hole punch to make my holes.

Now I just scribe a line. Then use chisels.

[JLSleather]

I don't care for that angled stitch, but he may be correct that the groove could "straighten" the stitch line.  Sounds like that could be right. 

But I do not believe that "use" causes stitching to recess.  In fact, thread stretches.  The idea for a groove was to recess and protect the stitching from catching and rubbing, which causes fraying and stretching.  I don't believe snagging or rubbing of the thread would cause thread to get tighter or deeper.  I have never seen any leather item that needed repair due to the stitching becoming too tight, or recessed too much.

Having said that, I don't generally use a groover (though I own a couple of them).  The bit about weakening the leather is correct.  In fact, that is true of about anything.. any time you cut it you weaken it (even a 2x4 is easier to break if you score it first).

 

[fredk]

Does it really weaken the leather so much that it matters? Perhaps in some items it does matter, but in a shoulder bag or belt pouch?

When I was involved in medieval re-enactment I had a regular flow of items to repair. Mostly it was where the thread had worn away and broken and the two parts had separated as the stitching had become un-done. In all these cases the original maker did not use a groove. In the repair I grooved before re-sewing. I never had one of my repairs come back to me.

[JLSleather]

46 minutes ago, fredk said:

Does it really weaken the leather so much that it matters?

Keep in mind also that the stitching holes themselves are already weakening the leather

I did have the opportunity to see a notebook (3-ring) that I made years ago, with a groove.  No issues.  But that was an item which is generally laid flat on a table, or stuck in a book bag, most of the time.

AND, it likely matters which way the stitching runs -- stitches running down a belt tend to be fine / stitches across the strap maybe not so good.

Edited May 12, 2017 by JLSleather

[alpha2]

I've gone to an impressed groove and don't use the cut groove these days. With soft leather, I don't use a anything but a scribed line. I did once cut a groove in a piece I'd already stained. That was a mistake!

Some items are a lot more likely to get abrasion of the thread, some quite a bit less so. 

[gmace99]

I tend to put a groove in the leather, where there is a lot of wear.  In a saddle I would do it on the flap. The leg is moving back and forth wearing the stitch out...
As to weakening the leather.  I doubt it will weaken it enough to matter. After all we thin the leather out when we are turning it. We do this when making belts to help the leather fold.
You will not get a nice slopping stitch in a small groove. However a straight stitch will look nice if done correct.
I would never use dividers to mark leather because they can scratch. I much prefer to use a single crease or a screw crease.
When the leather is getting flattened . Then that is wear. If it is doing that then you would be better putting that groove in

[Tugadude]

3 hours ago, alpha2 said:

I've gone to an impressed groove and don't use the cut groove these days. With soft leather, I don't use a anything but a scribed line. I did once cut a groove in a piece I'd already stained. That was a mistake!

Some items are a lot more likely to get abrasion of the thread, some quite a bit less so. 

That's a nice middle ground.  A crease compresses but does not weaken the leather and yet allows the thread to sit down a bit.  I agree with Nigel but don't get dogmatic about it.  If you groove and are happy with the results, then keep on groovin'.