How To Cut a Small Deep Slot?

ddavelarsen

ddavelarsen

Joined
Dec 7, 2000
Messages
5,179
Okay folks, here's one that's giving me fits. I need to make a slot about 95 thousandths wide and 3/16" long; the kicker is it has to be almost half an inch deep.

I've drilled two holes but have broken about half a dozen saw blades trying to connect them and have hardly made a scratch.

I haven't spotted a mill that small that long and doubt whether my setup could be accurate enough to cut one side then connect from the other.

I'm beginning to consider making a mortised guard but that really bugs me.

Any other suggestions how I might pull this off?
 
Square drill bits? Does it have to be rectangular all the way threw? If it doesn't why not drill most the way from the back and make a punch the size you need and punch from the finished side.
 
EDM [electro discharge machining ] would do it and probably water jet machining.
 
Mill from the back way oversized (as long as it will be covered by the handle) leave about .090 on the front. Now use a 1/8" end mill to rough in from the front a couple thou undersized then file to fit.
 
shape a piece of steel like the knife tang, and pound it through the guard while its at a yellow heat. thats how i do it. anyone ever notice the hardest part on a knife is the hilt?
 
Dave, perhaps I am in error but I thought you had a small mill. If that be true all you need is a slitting saw.

RL
 
Dave, I measured the depth of cut on a 5/64 2-flute endmill at about .275-.290. Perhaps that would allow you to at least connect the dots form front and backsides and allow you to finish with a ground down sparkplug file? Slow, but it would get you there.
 
oops! I missed the part about only being .095 wide. You could use a 3/16 or 1/4 mill from the back and then drill small holes and connect the dots from the front. That way you only have to cut and file a very thin section.
 
Well I knew you guys would figure this out for me. :D I'll make a bigger hole in the handle end and mill the blade end. Sheesh - I've probably asked this same question before. For sure I've read the answer. :rolleyes:

Thanks for the help gents!

Aside: My son Adam and I took a break to punch holes in 25-yard targets. Dang newbie made me look like I had a bag over my head! He flat put .45s through about the same hole, over and over...
 
You guys will have to excuse me, but what's a slitting saw?

I am always looking for better ways to slot guards...usually I drill a series of holes in the guard and then mill the "webbing" out. I have some end mills in 3/32 the length of cut is 1/2". They break pretty easy though.

Matt
 
It's like a circular saw blade on a table saw only real stiff like a mill. Using the right tool for the job is a wondrous thing. You'd use one if the guard had a slit for a full tang as opposed to a hole for a stick tang knife. I described my need poorly; if I were actually making a slot that's what I'd have used but of course I'm making a rectangular hole.
 
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