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How to create raised tread pattern in stainless with a punch or chisel

nickfracture

Plastic
Joined
Feb 9, 2021
Hi all,

I am very much a novice at metal fabrication, and I'm looking for some advice on a small project.

I'm looking to recreate a motorcycle brake pedal from an old Harley out of stainless (see links below for good quality images). The pedal has a tread pattern on it, made from raised divots in the steel. They appear to have been made by digging into the steel on an angle with some sort of chisel or punch? Perhaps using a die or guide?

Can anyone give me some clues as to how I could go about recreating these? Ideally by myself with hand tools, or what type of shop I could take this to?

Thanks!!

Dropbox - IMG_5991.jpeg - Simplify your life
Dropbox - IMG_5992.jpeg - Simplify your life
Dropbox - IMG_5993.jpeg - Simplify your life
 

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I don't know about that pedal, it looks pretty crude, but for the look you want, I think you'd use a dimpling die pressed from the back side. Or, start with a piece of metal that is already dimpled.
 
If you use the dropbox links you can zoom in to see them better.

I would put a 45 degree angle on a punch and see if driving it at an angle to raise the bump, then hammer bump to smooth it a bit, heat for smoothing might help. Get a scrap piece and try to replicate, might have to try different angles or techniques to get it to look right.

Edit: It could be that the raised part was originally left kind of sharp for grip, the current profile is after years of wear.
 
I've seen it done with an ironworker punch station.
IIRC a 1/4" punch was installed, and the die button installed was a 3/8" dia.
 
If you use the dropbox links you can see they were not punched from backside. I would liken it more to the start of an engraving, just a bigger punch and deeper gouge.

I did not follow the linky. I just looked at the posted pix.

however, who cares if the backside of the originals is not punched ?
 
I would liken it more to the start of an engraving, just a bigger punch and deeper gouge.

Yes, you're on the right track. There is an oval-shaped gouge leading into each bump.. They have definitely been dug up from the front side, rather than being punched from behind.
 
Back in the day that's how rasps and files were made. The teeth were raised with a hammer and chisel, one at a time, in the desired size and tooth form..........Bob
 
however, who cares if the backside of the originals is not punched ?

If trying to match another piece, or make it look original (no idea if that is factory original), then you have to use the same techniques.

Nick, I would sharpen a punch at 45 degrees and come in at about 45 degree angle, your workpiece will need to be well secured so all the energy of blows goes into raising the burr, instead of just sliding the piece across the work bench. Probably going to take some practice so you don't punch all the way through.
 
Make a die that has the raised dot pattern
Then a punch to make the gouge that would be forced into the die to give the dot shape.

Or could be do the gouge then use a die to uniformly form the dot and gauge.

Wouldn’t be surprised if it was done hot
 
I don't think you have the tools at your disposal to press the dimples.

Have you though of Drill and Tap 6-32 holes, then install round head screws for the dimples. Fill the heads with 60-40 soft solder if required. Stack the screws in place on the back side and file smooth.

Roger
 
My earlier comments were made with the assumption that the goal would be to achieve a result that is attractive, uniform, and long lasting. That's why I said the part shown is pretty crude...it's someone attempt (I assume) to achieve a look but didn't quite hit the mark.

If the goal is only to have a pedal with bumps, then all sorts of methods will work. If you must use frontal assault, you'd need to find a way to ensure a very uniform location of each bump, and control the depth of each gouge. That's a lot of work, when starting with a dimpled piece of steel would most likely be better anyway. Lastly, a gouged-up bump will seldom last long due to the shape of the bump....a die-dimpled bump will have noticeably longer wear.
 
There are a lot of ways to do this but you specifically asked for a method that you could use basic hand tools. If I had to approximate what you have there, I would mark out the pattern you want and drill starter holes where you want the dimples. Not all the way through, just deep enough to start a half round cape chisel and keep it from sliding off the work. Support the work well and raise a divot where you want the dimples. You can dress them down if they are too sharp or look uneven.


chisel.jpg
 
Wood rasps are still hand made and here is a video of a French company that is well known for expensive and very good tools.

The Making of Auriou Rasps - YouTube

You can see that a skilled craftsman can create the teeth with a hammer and chisel very quickly without using any device to locate the punch marks. They say that the slight irregularity in tooth locations makes a rasp perform better.

Larry
 
I doubt it was done by hand. Who would make the bumps by hand, then cut the oval hole which ruins a bunch of the bumps they just made. I am thinking some kind of sliding press made the bumps then the oval hole was cut.
 








 
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