Strap Cutter Curving

[TomG]

I've been using the popular strap cutter for many years and have meant to ask this question, but never remember when I am on the boards <g>
Whenever I buy a new side, I use a straight edge and clamps to cut a perfectly straight edge. As I cut my straps, that edge begins to curve inwards.
I have racked my brain trying to figure out why and how to stop it.
Any clues or suggestions?

 

[tsunkasapa]

It is caused by the stretch of the leather. I know of no way to stop it.

[fredk]

As I pull the cutter along I also slightly turn the handle part into the uncut leather, I also push the leather forward into the blade and also the uncut area into the handle part of the cutter, just gently. Just enough to make the leather to handle a tight fit

[Scootch]

Is this the common wooden type of cutter?  I've never had a problem with curving but only on the last 3 or 4 inches of the strap just before it releases from the cutter.  One issue I had has the strip would get slightly wider as I cut.  The part that held the blade would slip a little under the wing nut. The firmer the leather the more it would slip.  Keep a sharp blade, tighten the wing nut with pliers and set the opening width to where it's not pinching on the leather that way you're not pull harder than you need to.

Scootch

[Matt S]

I have found that some hides tend to have "hidden" tensions that cause the strap to curve a little. Grain direction (and where/what direction) the pieces are cut seem to have an effect, as does the general quality of the hide.

Slight bend in straps tends to be stretched out or overridden by use quite quickly. Further manufacturing steps can eliminate or exacerbate the issue -- I've had laminated straps corkscrew when I've forced excessively curved pieces together with glue. Unless it's really bad it all tends to come out in the wash after sewing, and if not I can force the issue by running it through my roller machine, or hammering, or staking it round a post. You could also aid the fibres slipping past each other by wetting or heating the strap but that risks damaging or marking the leather.