CPM154 Issues

Discussion in 'Knife Steel Reference' started by BrandantR, Jun 20, 2017.

  1. BrandantR

    BrandantR Well-Known Member

    I tried some CPM154 steel from a new supplier this last weekend and I ran into some problems that I've never seen before. As I was drilling some pin holes through my blanks for a set of kitchen knives that I'm getting started on, I got that high-pitched screeching that happens when an HSS drill bit hits hardened steel. This happened on about one hole per knife blank and the other holes went just fine. I probably should have just thrown the blanks into the oven and annealed them, but I was stubborn and in a hurry and burned through several new bits before busting through with my holes. This whole thing got me to thinking, does CPM154 work harden, or did I just get a bad piece of steel that wasn't fully annealed?

    I usually buy my steel as HRA (hot rolled annealed) but the new website where I purchased this particular steel from didn't specifically say what state the steel was in when I bought it. This might be the reason they were so much cheaper than other websites. I've been working with CPM154 for several years now and this is the first time that I've encountered this problem. Can anyone shed a little more light on what the problem may be?
     
  2. bladegrinder

    bladegrinder Well-Known Member

    I've never had problems drilling thru CPM-154 Brandant and that's my main steel. I'm sure it would work harden if your using a dull bit.
    I use a drill doctor sharpener a lot, especially on my lightening hole bits, for pin holes I use cobalt bits.
    I get all my CPM-154 thru Admiral steel.
     
    Last edited: Jun 20, 2017
  3. BrandantR

    BrandantR Well-Known Member

    Yeah, I've never had any troubles drilling CPM154 either, and my drill bits were new and sharp. I think I just got a bad piece of steel that just wasn't fully annealed and still has a few, small hard spots. Just thought I would put the question out there.
     
  4. John Wilson

    John Wilson Well-Known Member

    I've never had this problem drilling CPM154, but I have had some with inclusions in the steel that didn't show up until hand sanding. They showed up as spots that were easily seen under decent lighting and no amount of sanding would get rid of them.
     
  5. bladegrinder

    bladegrinder Well-Known Member

    Is it possible you got something other than CPM-154 from this new supplier, I would think with the technology required to make CPM steel they would have the annealing part down, of course sometimes things slip thru the cracks. the only drilling problems I seem to have sometimes are with Damascus and mosaic bolsters, depending on who made it.
    Drill speeds make a big difference too.
     
  6. Smallshop

    Smallshop KNIFE MAKER

    Perhaps if the material were at the extreme tolerance of the alloy content on one of the tougher/harder components or at the high of the annealed hardness spec, it would drill tougher and work-harden quicker even though you are keeping drills sharp with the drill doctor...possibly it is not a tough spot but a drill getting dull quicker than usual. If the screeching drill cuts the next hole fine without resharpening then I would think it could be hard spots.

    Try drilling with a slower rpm and not doing as many holes per sharp as you were previously.
     
  7. BrandantR

    BrandantR Well-Known Member

    I suppose it is possible that I got something other than CPM 154, but that's what the label on the steel said when I got it. I just ran the blades through heat treat. I'm going to slip out to the shop tonight and test the hardness. That will tell me for sure if I have some other type of steel.

    Thanks everyone for you input. I appreciate you taking the time to comment.
     
  8. BrandantR

    BrandantR Well-Known Member

    Well, I broke out the hardness tester last night and all four blades were spot on for hardness. So, I guess the metal is definitely CPM 154. I have quite a bit of steel left over from this project, so I'll just have to watch it on the next project to see what happens.
     
  9. bladegrinder

    bladegrinder Well-Known Member

    Try cobalt drill bits, I think they make a world of difference. you can find good prices for them on ebay.
     
  10. BrandantR

    BrandantR Well-Known Member

    Cobalt bits are definitely a much better bit than HSS. If I run into more problems, I'll have to grab some cobalts and go to town.
     
  11. samuraistuart

    samuraistuart Well-Known Member

    If cobalt is still giving you problems, you might want to consider a carbide bit. A little expensive, but worth it when you need them. Also, many masonry bits have carbide tips on them, and will drill thru hardened steel as well. The advice given is to run at full speed with no coolant, and that the hole will be a smidge larger than stated bit size. Not exactly accurate, but for example a 1/8" carbide tip masonry bit will drill a .130" hole instead of .125", more or less. I've done that once a few years ago when I had the same problem. It worked.
     
    Last edited: Jun 23, 2017
  12. scott.livesey

    scott.livesey Dealer - Purveyor

    did you use oil/water cooling when drilling? ordinary M2 HSS bits can heat quickly when drilling steel. CPM154 does not work harden, But you could get a small area under your drill bit hot enough that when you paused, it cooled and hardened. you should also be running your drill press at the slowest speed and be gentle on the feed.
     
    Last edited: Jun 23, 2017
  13. BrandantR

    BrandantR Well-Known Member

    Thanks for the replay, Scott. I always use plenty of oil, slow speeds and slow feed rates when drilling. I'm 99% sure that the piece of steel that I got just wasn't fully annealed.
     

Share This Page