Having trouble with a motorized edge burnisher

[blackmad]

Hey all -

 

I know this question gets asked all the time, so my apologies in advance if anyone is bored of answering people about how to burnish edges. I've tried to read a bunch and still found myself a bit stuck.

 

I work with thick harness-style leathers and I'd like to get nice rounded burnished edges on them. I've never had great luck with burnishing by hand, so I thought I'd try a motorized burnisher. I bought this cocobolo burnisher: http://proedgeburnishers.com/index.html and put it on a 1/2hp motor from harbor freight that seemed to be commonly recommended https://www.harborfreight.com/6-in-buffer-61557.html

 

I took ~10oz leather, went over the edges with a #2 (I think) edge beveler - https://photos.app.goo.gl/uAs6X5AHpAomKu9y8

 

and then, trying a combination of different saddle soaps on the burnisher, tried to round the edges, but I ended up with a much more visible, lumpy, not smooth, not even especially round edge - https://photos.app.goo.gl/qs1qacQ1Wz6ptCsb8

 

I'm not happy with that edge. I've read a bunch about how to burnish and am still a little stumped.

Reading over the pro-edge burnisher FAQ, I'm realizing that perhaps I did the wrong thing by putting the wax on the burnisher first rather than on the leather. I will try that next. Anyone have other suggestions of how to get a better edge?

 

A related question is - is there some trick I'm missing to using an edge beveler? The best approach I've found for myself is to put a metal ruler over the piece I'm working on, close the edge, and try to use that as a guide for the beveler. Otherwise I find myself making waving lines that I can see in the finished product, or occasionally veering off entirely and taking a nasty bite out of the leather.

 

Thanks,

David

[Matt S]

Hey David, the trick with edge bevelers is to keep everything as equal as you can. If you change pressure or angle the amount of leather it removes will vary. I keep the strap still and walk along the bench, keeping the beveller at the angle I've found most effective by keeping the fingertips of that hand in contact with the bench. It's also essential to keep your tool as sharp as possible, I strop every few belts using a piece of string with abrasive paste rubbed into it.

Burnishing can be a right pig until you got the right combination of pressure, compounds and speed for each particular leather but I've never had much success with paste saddle soap. These days I mostly use diluted PVA glue, but most water based glues will work. That's what him tragacanth gum is, but again I never had much success with that stuff. Also, with motorised burnishers, the leather needs to be wetter than with hand burnishing.

[steelhawk]

The tool you bought runs at 3450 RPM. My understanding is that this RMP level is too fast for burnishing.  The burnishing machines I have seen can operate much slower. The Cobra one has a variable speed motor from  2000 to 3450. The machine Weaver Leather sells operates at 1725 RPM.

Edited February 16, 2020 by steelhawk

[Hildebrand]

I have a similar set up. You have to be very careful with how much pressure you use.  To much pressure and it’s not going to give a nice finish. That’s the way I combat the speed issue.

Todd

[Matt S]

12 hours ago, steelhawk said:

The tool you bought runs at 3450 RPM. My understanding is that this RMP level is too fast for burnishing.  The burnishing machines I have seen can operate much slower. The Cobra one has a variable speed motor from  2000 to 3450. The machine Weaver Leather sells operates at 1725 RPM.

That's pretty commonly said but it's my experience that there is no speed that is too fast for burnishing, it's just that there are different techniques for different speeds. The important speed is the surface speed not the number of revolutions per minute. RPM is a factor in determining the surface speed but literally three times less important than wheel diameter (pi*diameter*RPM). I find that faster wheels tend to be less forgiving of mistakes than slower ones but if you have your technique dialled in they produce just as good results, and far quicker than slower ones. For me there's the added benefit of not being tempted to over-wet the edge and create mushrooming. It's also quite essential to keep the edge cool and lubricated -- after all the heat is what does most of the burnishing, but the temperature at which leather burnishes is pretty close to the temperature at which it burns.

I've been using a 2" diameter wheel on a 3000RPM motor for several years now. There was a bit of a learning curve at the beginning but it works well, and fast. I use different compounds and techniques on different leathers -- veg or chrome, thin, thick, soft, hard, it all works but each works differently. As @Hildebrand says, careful and consistent control of the pressure is half the battle.

[chiefjason]

Based on that edge pic I have some assumptions.  Too much pressure.  Too much time spent against the burnisher.  Not enough lubrication.  

When I burnish my holsters I use moderate pressure but kind of swipe the edge back and forth a couple of times.  I keep the piece moving.  

I've started using Tokonole for my burnishing too.  I've tried lots of things and it is far and away the best thing I've found.  I usually wax the edge afterwards to fill in any of the small inconsistencies that don't get burnished out.