method for bolster/guard slots

S

Skiller1nc

Joined
Jun 27, 2016
Messages
302
I am about to do a run of kitchen knives and would like to do copper guards/bolsters in front of my wa handles, my plan is to use some .1-.15" thick copper. I've always done the slot by hand, drilling, and then hand filing (no mill access). How feasible would it be to have them water jet? I haven't been able to find any info about this being done and I can see the inner corner radius being a potential problem but since the knives will be waterjet and basically identical, could I have a slot waterjet a few thou undersized to make fitup much easier?
 
A water jet would do the trick but a CNC mill would be much quicker and produce a better quality slot. The biggest issue with a mill would be the corner radiuses left inside the slot. Though if you’re only going .15 thick a 1/32 end mill could be ran to leave a 1/64 radius in the corners. A mill also has the capability of at least roughing in a radius on the guard that matches the radius on your water jet blades. Like you said it doesn’t make for perfect fit up but it gets you 95% of the way there. That’s how I normally do it.
 
Contender Machine said:
A water jet would do the trick but a CNC mill would be much quicker and produce a better quality slot. The biggest issue with a mill would be the corner radiuses left inside the slot. Though if you’re only going .15 thick a 1/32 end mill could be ran to leave a 1/64 radius in the corners. A mill also has the capability of at least roughing in a radius on the guard that matches the radius on your water jet blades. Like you said it doesn’t make for perfect fit up but it gets you 95% of the way there. That’s how I normally do it.
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Do you do these yourself or have a shop do them? I got a few quotes online for a batch of 50, they are 1"x.75" with a .1x.75 slot, and the quotes are like $30-50 per part, which for a $1 piece of copper and the little labor it would take seems crazy.
 
Yeah I do them myself. Unfortunately most machine shops wouldn’t want to mess with a small job like that. I might be able to help you out though. Send me a PM if you can.
 
Skiller1nc said:
Do you do these yourself or have a shop do them? I got a few quotes online for a batch of 50, they are 1"x.75" with a .1x.75 slot, and the quotes are like $30-50 per part, which for a $1 piece of copper and the little labor it would take seems crazy.
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They ask $30-50 for cutting just ONE slot in copper ???????????????
Why you don t cut them on laser fiber ? Laser fiber is much much cheaper than a water jet ? If you are here in Macedonia they will cut say 100 guards with slots like that for 10 $ for 30 seconds !
$30-50 for just this ???
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Natlek said:
They ask $30-50 for cutting just ONE slot in copper ???????????????
Why you don t cut them on laser fiber ? Laser fiber is much much cheaper than a water jet ? If you are here in Macedonia they will cut say 100 guards with slots like that for 10 $ for 30 seconds !
$30-50 for just this ???
5CmuicM.png
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Yes, $30-50 per piece for one of those. if you only order one it's like $180, and if you order 50 it was like $30/per. Can you laser cut copper I thought I recalled reading somewhere you couldn't do to its reflectivity or something idk?

Edit: i googled fiber lasers, they can cut copper, IDK what I was thinking about but it wasn't correct

Edit 2: I am not crazy, old lasers did have problems with reflectivity, "Traditionally, a CO2 laser was used to cut copper due to its ability to cleanly cut thick material. However, the sheet of copper had to be coated with a graphite spray or milk of magnesia in order to prevent reflections, which could damage the laser."
 
The smaller desktop style marking lasers have more trouble with reflectivity. Engraving through the color red is harder to do than the color black for example.

The biggest downside to a laser is the surface finish. It’s not as nice as a machined finish.
 
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Have you thought about a jewelers saw? You can cut into the corners and get really close to a precise scribe line since these pieces are so small. Or since the knives will be a precise size from water jet why not punch the slot? Copper is pretty soft you could probably make a custom punch to make a near perfect slot that could be press fit onto the knives.
 
I use a jewelers saw and #0 blade to #2 blade (depending on the material and thickness).
Mark the slot slightly undersize on the guard.
Drill four small holes at the corners of the marked slot.
Use saw to cut out slot.
Use an equaling needle file to clean up slot for a perfect fit. The whole process takes one to five minutes (depending on the material and thickness).
 
Stacy E. Apelt - Bladesmith said:
I use a jewelers saw and #0 blade to #2 blade (depending on the material and thickness).
Mark the slot slightly undersize on the guard.
Drill four small holes at the corners of the marked slot.
Use saw to cut out slot.
Use an equaling needle file to clean up slot for a perfect fit. The whole process takes one to five minutes (depending on the material and thickness).
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Hey Stacy can you recommend a brand of jewelers saw blades?
I've come to realize that the cheap ones I bought are not a good deal.
 
I use The Stuller House brand. Pike's platinum is a good commercial brand. Pikes' gold works pretty well, too.
 
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