Plasma torch?

G

grizzled gizzard

Joined
Aug 31, 2010
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726
First timer with stock removal.

I had a batch of S35VN blades waterjet cut, but I didn't ask for skeletonizing of the full tang blades. A mistake, I know for sure now.

I have a nice plasma torch, but I'm guessing that's asking for trouble. Can it be done minimally, then grind the tangs flat?

Could I take them to a waterjetter?

Should I leave them handle heavy, without epoxy holes?

I could not believe that I can't drill holes in annealed S35VN. Completely destroyed a new center bit in 3 holes, and I was using a mister. Broke a carbide bit just as easily.

What can I do?

I have three 3/32 pins going through. Is that enough for a medium duty blade?

As always, Thanks for any tips.
 
Since the blanks are still not heat treated I would look into a shop that does small tool setups with water jet or laser cutting. If the shop you originally had them done at only does full sheet they won't want to try and fixture each blade to make the cuts but you should ask them. If (it's a big if) they still have the scrape sheet they originally cut from they can possibly place the blanks back into the sheet and run the new program. It still might be cheaper to have a new batch re-cut.

I believe a plasma cut wouldn't be worth the cleanup involved in it.

Good Luck
 
You could use the plasma on the tangs as any decarb there will not effect the cutting surface and you should not get any warpage that you can't straighten before HT. I don't understand why you cant drill it in an annealed state. Didn't know it was that hard before HT. Anyway you work hardened it?
 
Thank you so much for the replies gentlemen!

Criminalhate, I did think about making a jig for the watterjetter, because I can easily see where that would be necessary.

Frank, I use a TW90, totally set up to grind wet, so it's not a grinder issue. I had never ground anything like S35VN, but I thought Aldo told me it wasn't too bad. I must have mis-heard.

SteelSlaver, I tried drilling the end of the full tang, so no work hardening, and absolutely no thermal input. I should post a picture of the bit. I've never seen a more completely destroyed bit out of many hundreds I've gone through.

I figured it wouldn't be easy, so I set up the mister with good coolant/lube added before I drilled a single hole.

The S35VN completely ATE the bit! As I drilled the first hole, I was tuning the speed of the press, and about 700 RPMs with a 1/2" center bit looked ok... at least for the first hole.

So the question is; How important is this in the first place? I've never made a full tang without drilling epoxy holes.

I've only forged full tangs with maximum distal taper, so it was never a matter of weight before, I was just trying to attach the scales as well as possible.

I've never put much thought into weight/balance before. Just the way I forged them seemed to work pretty well.
 
A center drill doesn't cut very well. 700 RPM is too fast for a 1/2" drill in this material.

A better suited drill turning an appropriate speed and fed properly can cut it.

Try a USA made 1/4" split point drill turning 500-600 RPM and fed hard enough to keep a curl coming out of the hole and reduce feed pressure as the point exits the back of the work.

Be warned, under feeding a drill in material like this leads to rapid wear and work hardening.
 
Thank you very much for your input, Nathan. I have no doubt you know exactly of what you speak. You're kinda one of my heroes, so it's great to get your input.

I didn't hear anyone against it, so I went ahead and skeletonized the tangs with the plas.

I must say I was very pleasantly surprised. It probably took 15 seconds to move from blade to blade. I skeletonized the whole tang in less time than it took to drill one hole. Warpage was very minimal, and the blades never got warm enough to handle without gloves.

It made a big difference in the balance and feel of the blade. Moved the balance point about 5/16" forward.

I hope to remember to take a couple pictures so you can see the difference. Truing the tang on the belt grinder went almost as well. I didn't spend a minute per blade.

IMHO, it worked very well.

Thanks again for the information guys. Much appreciated!
 
I didn't think the skeletonizing needed to be pretty, so I get no points for that. It was fast and IMHO, very effective. They all came out similarly.

I don't know if you can make out the center bit, but I've never seen one so thoroughly destroyed. It was a high quality bit too.

Nathan, I hope you don't mind if I ask you before I need to do drill an inordinary hole again. I can see that you were exactly right. I have a couple of good machinist friends, but they've never heard of S35VN. :thumbup:



 
That bit was chewed up because it is HSS that you heated to the point where it was softened. If you are seeing chips any darker than straw with HSS tooling, you are getting too hot. With carbide mills even fairly dark blue is ok, but you are trying to cut soft tool steel with tool steel that you have softened.

One other thing to keep in mind is that a center drill is only intended to start and chamfer a hole. Using the the full diameter for a drilling operation goes well beyond that.

-Sandow
 
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