I was hoping to reach out to someone with more experience on this subject. I have been using the fireball tool, fixture table drill guide to build my own table, however, as I have been using it, I have gone through 3 carbide cutters in less than 200 holes. I have been making sure that the bit goes in smoothly before operation, and have also been using plenty of lubricants. Specifically WD-40 as mentioned in his video.
Am I missing something? What could I be doing wrong? Any help would be amazing as this project could turn incredibly expensive, and/or just might make me pay for a company to laser cut my top for me, and then I will just ream them out with a 3/4” reamer.
Can you give us more information, like the brand, shape and style, speed and feeds. Does your drill have power feed? What material and thickness are you drilling?
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This is probably where my inexperience will definitely show lol
The brand is Nitto, it is a 2” depth cutter, with a 3/4” diameter. As for speeds, I was using it on the “recommended cutter speed” at 475rpm (Milwaukee Brand) it has a twist drill speed of 730rpm. It does not have a power feed unfortunately, so it’s all by feel. I try not to apply to much pressure, so as not to create excess heat. The material thickness I am drilling is 3/4” plate steel.
You can use WD-40, but Nix Stix or some other metal cutting lubricant is much better for steel.
Also, I haven’t heard of Nitto, but it sounds like a cheaper Chinese brand. You’ll probably end up spending less money if you go with a better brand of cutter like Hougen or Fein. I’ve found these types of cheapo ones okay for the occasional use but once I started buying quality blades it was obvious they actually cost less per amount of work one will last through.
The brand is one I sourced from McMasterCarr. Attached is the link to the brand. However you may be correct and I just need to purchase a higher quality cutter. The one used in the demonstration video was a champion cutter, and perhaps they will work better and evacuate chips better with the reduced shank design considering it’s already 1” down in the drill guide.
https://www.nittokohki.com/tools/products/cutters/jetbroach-carbide-annularcutters/index.php
I may be quite wrong about those being cheaper cutters. I’m just serious about my home shop but there’s a ton I don’t know. I would definitely try some better lubricants and slower speeds as a first go at it, though. Since you’re using carbide you probably don’t have to drop the speed a ton, but less heat means it’ll definitely last longer regardless.
There seems to be a sweet spot in pressure, too, where the bit is digging in but not too aggressively.
It’s definitely worth trying everything you suggested. Which brand have you had the best longevity out of?
I’ve not done what you’re doing so I don’t think I can offer a good comparison, but I’ve been asking around and eyeing a set of Hougen cutters as I’ve got a pretty old set that was used before I got it and hasn’t shown much wear to spite punching a lot of 5/8" and 3/4" holes in A36. However, when I say “quite a few”, I’m probably only talking about 50-60 each in the year I’ve had them mostly in 1/4" and 3/8" plate or angle. I’ve run them on my hand drill at maybe 70-100rpm and at similar speeds on my mag drill with nix stix cutting lubricant and some flood coolant setups I jury-rigged.
In short, try some purpose made lubricants and dropping the RPM and you’ll probably see improvement but I think what I’m doing is a lot of apples to oranges compared to what you’re doing. Hopefully somebody with more experience than me can weigh in on comparisons since I’m mostly passing along what I was taught by old timers.
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You said you try not to apply too much pressure, but it’s possible that could be part of the issue. You need to be making big enough chips for the heat to be carried away with them. If you don’t feed aggressively enough you’re making small cool slivers and all the heat is staying in your cutter and material. Shooting from the hip, I’d use better lube and more pressure when you’re drilling, but I could be misdiagnosing the problem due to not being there seeing it in person.
@HenrysWorkshop suggestion of lowering the rpm effectively allows you to be a bit more delicate like you want, while having a speed/feed combination that still produces larger chips.
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I will definitely try all of your suggestions once I have some new bits in the mail. Hoping for some better results this time
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I am not a machinist and have used almost no carbide but from my HSS drill experience, low speed and relatively high pressure results in the longest drill life. I also agree about using a better cutting fluid. Even Ridged Cutting fluid might be a better choice.
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I’ll start off by saying I’m no expert and I’m just sharing my own recent experience.
Last week I drilled a 1” thick piece of plate steel 15 rows by 15 rows for 225 total holes with the Fireball drill guide. I used one Hougen HSS 3/4”x2” cutter for 220 holes and one “Steel Dragon Tools” carbide 3/4”x2” cutter for the remaining 5 holes, using only WD-40 as cutting fluid. The mag drill was a borrowed Hougen 904 which did not have speed control.
I found that feel is the key here as well as making sure the drill is sitting flat in relation to the drill guide. If the top is bowed or there are metal chips under one or the other, that slight misalignment would make the cutter not want to start cutting no matter how hard I pulled on the handle. Any slight misalignment wouldn’t allow the cutter to grab and it would just be spinning against the drill bushing. I had to move the drill guide and drill the hole from another angle. I speculate that could potentially wear out a carbide cutter quickly if the carbide is chipping due to bad alignment.
But when everything was good, you’d feel the cutter grab and you’d kind of know how much more or less pressure you need to sustain that cut. I’d start the cut with a flood of WD in the hole with moderate pressure and I’d retract the cutter every now and then to spray it with WD and then keep going til it was through.
Oddly enough, about 200 holes in I decided to try a thick cutting fluid like rapid tap on a few holes and the cutter wouldn’t even grab. I actually thought I had burnt out the cutter, I was hanging on the handle trying to get it to start cutting. Switched back to WD and it cut fine again.
I only bough the carbide cutter because the HSS one would not cut a few spots that had weld repairs and were thus hardened. It’s a cheaper cutter, got it on eBay for $30 and it worked very well. I can’t speak to the longevity of it but I was impressed given the price.
Long story short, if you’re cutting mild steel, HSS and WD-40 can work very well. If you’re burning through carbide cutters, I would imagine something else is the issue. As someone else said, too light of pressure is also bad and can wear out a cutter prematurely because it gets hot instead of cutting and also work hardens the metal as it’s just rubbing on it.
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