Drilling a thumbstud hole in M390?

arskrg

arskrg

Joined
Aug 15, 2011
Messages
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I like my Lionsteel TRE-g10, but I'm thinking of adding some thumbstuds.
Is this something I could easily do with a drill press?
I'm guessing I should start with a smaller bit and work my way up.

Should I worry about cracking the blade up toward the spine??

Going to remove the studs from a mini-grip to use on the TRE (and then grind a bit of the spine off to wave the mini-grip).
 
Although I don't have any experience drilling M390, I do have a lot of experience drilling hardened stainless steel.

I assume that since you are installing a thumbstud that you are drilling a small diameter hole. It shouldn't be necessary to use more than one drill bit. Just use one carbide bit in the same diameter as the hole you want to drill. And make sure you clamp the blade down tight.

I have a 5 speed drill press. I use 1100 rpm for anything smaller in diameter than 1/8th". I use 620 rpm for 1/8th" or larger. And I've always had great results and never burned or ruined a bit. 620 rpm is the lowest speed my drill press has, 1100 is the second slowest. Go too fast and you burn out the bit. Go too slow and you won't get the hole drilled. I also use plenty of cutting/tapping/drilling fluid.

I get all my carbide bits from McMastercarr.
 
Yea, I didn't think about hole size. That ram I stated would be for a larger bit, like 1\2" size. For a hole rought 1\8" you would want a higher rpm, say around 4-600 rpm
 
If M390 is a high speed steel (I'm not up on every latest knife steel these days) then yes you can drill it with a tungsten carbide drill, but you'll want to keep the speed very low - in the 200 RPM range would be great for a drill around ⅛" diameter.

HSS contains quite a lot of differing carbide forming alloys, so there are plenty of carbides present that are very hard on drills. Drilling HSS is going to be pretty much use the drill, then sharpen the drill. I would definitely recommend using a cutting oil as already recommended by another user.

If you hear any weird crunching noises or high pitched squeaks/squeals, get the drill out of the hole immediately and inspect the cutting edges for damage. Resharpen if necessary. You might make it through in one go, you might not.
 
Perfectly stated.
I will add two sentiments.
One, check and see how much the drill bit is, carbide bits are not cheap.
Second, be VERY careful with ANY side torque. Those carbide bits will snap in a second if any side movement is present.
Somebody correct if I am wrong but dont carbide bits like to be run at a higher rpm than hss to be effective or maybe it is just that you can run them at higher rpm than others
 
Wow, It's only been a week since I started this thread? Feels like it's been two or three.
Lame-o update, I decided to sell the knife rather than modding it.
Mostly because I didn't like the weak flipping action.
Also because I had too much trepidation toward drilling this hole.
I would be so mad if I'd effed up a $200 knife.

Thanks anyway for the advice, everyone.
Maybe one day your thoughts will come in handy for someone else.
 
nick_30 said:
Perfectly stated.
I will add two sentiments.
One, check and see how much the drill bit is, carbide bits are not cheap.
Second, be VERY careful with ANY side torque. Those carbide bits will snap in a second if any side movement is present.
Somebody correct if I am wrong but dont carbide bits like to be run at a higher rpm than hss to be effective or maybe it is just that you can run them at higher rpm than others
Click to expand...

An ⅛" TC drill won't be too expensive, probably under $20. For drilling soft steel, one would normally run carbide drills at about 300% - 400% of the speed you'd run a HSS drill. Running too slow can cause cold welding of the steel to the drill's cutting edges, and once this breaks away it will often take some chunks of carbide with it - et voila, dull drill. However, just as with HSS drills, the harder the material one is attempting to drill, the more the speed needs to be reduced.

For carbide it's especially important not to get the drill too hot while it's being intermittently doused with coolant or cutting oil - if this does occur, it can cause micro-fractures and crumbling of the cutting edge on a micro level, which will result in instant dulling of your drill and possible tool breakage.

It is even possible to drill HSS with this small of a TC drill using a hand drill - I just did it the other day while making a straight razor from HSS as my drill press was down. However, the warning by nick_30 is not wrong. Using carbide tooling is best when everything is rigidly mounted and held - if the TC gets in even the slightest bind because of misalignment and grabs, it will snap crackle pop. Case in point: to drill the ⅛" hole in my razor with the hand drill, I needed to resharpen the drill 8 times to get through!
 
Artu is a brand name, yes? Then properly one ought really to say Artu Tungsten Carbide or TC-tipped drill, to avoid any confusion amongst neophyte members, as Artu does make HSS drills also, and you know that someone somewhere would try one if it wasn't made perfectly clear.
 
Artu is indeed the brand name, and i wasn't aware they also made standard HSS drills.
I got pointed to this brand by an Australian knifemaker and just ordered a couple from E-Bay.

It's indeed a carbide tipped drill but i don't know what type of carbide is used for the insert, as when touching it up on the Tormek silicon carbide stone it feels both harder and more wear resistant compared to the carbide insert in an average stone mason drill (which i also tried on the M2 knife)

This is the 6 mm Artu drill bit i have:

 
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