Curved Clips: Cut on the wheel or the platen?

Josh- Thanks for taking that the way you did. You always inspire me with your open minded and "defenseless" approach. I always have it in mind that even someone who knows nothing about knives could, even accidentally, give me a great idea.... but I definitely need to work on the part about not being offended by some other makers' comments. :eek:

I don't draw file my clips because I like to do them post hardending, and can typically start sanding them with a fairly fine sand paper. BUT, there are times when one just doesn't want to cooperate, and when that happen I use a draw filing motion--- but with a piece of steel that I slap PSA paper onto and cut trim the paper so it's flush to the edges of the bar. I use a 1" wide bar for straight clips, and a little 5/16" wide bar for curved clips.


On a side note, oftentimes many of the issues a fella is having getting his clip grinds even are stemmed from his blade not being straight, evenly tapered, and with a centered edge.

It all goes back to my Dad's house framing days mantra- "Start square, stay square." :)

There's no other way to end up with a square building or square knife, for that matter. Good advise!
 
My radiused platen idea came directly from my friend Mike Vagnino. It's just a piece of some 5/16 or 3/8 tool steel (I think I used O1, it was whatever was in my "too short for a knife, but too good to scrap" tool steel bin at the time ;) :) ). Drilled and tapped it to bolt up to the KMG flat platen tool arm. I'd guess the radius is equivalent to a about a 6" to 7" wheel (keep in mind, the radius is oriented so that it's round from side to side, not top to bottom).

Nick, I've read this three times and I can't picture what you're describing. Do you mean a 3/8" round bar, or a 3/8" plate that's radiused to 6 - 7"?? :confused: :eek:

Edit: NM, I figured it out: 3/8" plate, radiused 6 -7" across it's width. You bolt it on and use a J-Flex belt, right?
 
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Patrice Lemée;10733656 said:
How do you make the radius on that? Eyeball it on the grinder? :(

I was wondering that too! :)

Either take a slice out of a 7" diameter cylinder, eyeball it, or get Nate to make a platen radius'd in the other axis ;)
 
Nathan would clearly be the most precise source. :)

I made a redneck radius gage and used it to check the platen while grinding it on the belt grinder. I did a little truing up by draw filing. There are several things you could do that would involve more precision... but mine is smooth and consistant, which is what matters.

BTW- I had forgotten that I made it more like a 10" wheel, not 6"

(and yes, my grinder bench is really that dirty! ;) )

DSCN4080.jpg DSCN4081.jpg
 
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Thanks Nick, I really appreciate you taking time to take pics and describe your process. Invaluable for slow folks like me. ;)

I must say I am a little surprised though. With how ana...errr I mean perfectionist ;) you are with everything in your shop (it's a compliment believe me, I am the same if just not as good), I thought dust extraction would also be top of the line. :(

Nathan would of course make a perfect platen but he is pretty busy as it is.
 
Nick,
Like Patrice, I also really appreciate it when you -- or any of the other makers that I really respect -- take the time to post photos of their specialty tools and equipment. It is helpful to read a description; but, for me, there's nothing like a photo. :thumbup:
Thanks.
Erin
 
You bet guys. :)

Patrice- I would like to get some type of dust extraction set up when I get the new shop set up properly, but the grinders are in a temporary setting right now.

I think I want to just get a blower to extract everything through some ductwork and blow it out of the shop. But I've also been keeping an eye out for a Torrit dust collector. They had them in the fab shops at the mill, and they really worked great... but they should considering those units are about $5k! :eek:

I also get a bit hung up on the fact that most photos I've seen of knife shops with dust collectors--- look to have a lot of dust all around the grinding area anyway. :confused: :foot: My grinding bench is normally pretty clean even without a collector of any sort, but my shop-vac seems to have been relocated to other areas for puppy cleaning, LOL. ;) :)





BTW- The nice thing about a clip grinding platen like this, FOR ME, is that you can do a curved turn out, even with a straight clip profile. Like this one. Of course there's some geometry going on with the curve of the "harpoon tip/raised clip" and the distal taper in the blade... but no matter, it would be 100 times harder to grind a clip like this with a flat platen.
cf4.jpg

Not to overplaster this photo on the forums, but Buddy's pro photo shows what I mean a lot more clearly. :)

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...most photos I've seen of knife shops with dust collectors--- look to have a lot of dust all around the grinding area anyway.

I think that this has mostly to do with the fact that people don't seem to put a lot of effort in the collector part. Sometimes you just see an open duct in the general area. Of course there is a limit to what you can do and not get too much in the way of the work. But still I am sure we could do a lot better. That's why I can't wait for your ingenious mind to start working on this. :thumbup:

And blowing outside if possible is much easier or in the case of the Torrit, much cheaper too.
 
Did like Nick suggested. Still need a little polishing but it's roughly a 10" diameter. 2 alignment pins and one small rare earth magnet pressed in. Now I need to fab a angled toolrest for good measure.

clip_platen1.jpg



clip_platen2.jpg


I can't wait to try it.
 
I do curved clips on a 4" contact wheel on a Rockwell 1X42 grinder. I use a lot of water. I notched out the base plate so I can move the blade downward with the tip leading.
 
It seems most of you guys are afraid of using a contact wheel! Contact wheels are your friend.
I grind clips vertically and generally grind swedges the same way, unless there needs to be a defined start on the swedge.
 
I'm not afraid of contact wheels. When I find a better, more consistant way to do something I stick with it. :)
 
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