Chris Dehmer, owner of Dark Horse Woodworks in Atlanta and a board member of the Cabinet Makers Association, recently answered our questions about transitioning from outsourcing CNC work to having his own CNC router. Before a live audience of about 150 CMA members at the CMA’s 20th-anniversary conference in Denver, Dehmer talked about many issues including how he deals with tooling on the new machine. Here’s a transcript of that part of the interview, edited for length.
Will Sampson: What were your decisions on tooling and tool holders?
Chris Dehmer: Because we had been using someone else’s machine, I had a pretty good idea of the tools we were using that we needed for that. We actually use a lot more now than we did then, just because it’s easy for me to do. We also have a 10-position tool changer, so we can put more in it. Despite universally pretty much everybody telling me I should have bought a drill bank, I didn’t. Some of that was money. Some of it was, “Do I really need that – $10,000 to be able to drill those holes a little faster?” I will admit when I’m watching that thing do this (makes up-and-down drilling motion) it gets a little bit maybe I should have bought that, but we’re just not a production enough shop to where it’s not a big deal to walk off and do something else while it does that.
Sampson: What kind of tools are you having in your tool library that you can use on the machine? For guys starting out, what’s the kind of basic tool kit that you’ve got to have?
Dehmer: Well, it probably varies for everybody, depending on what you do. We do a qualified blind dado. We predrill. I’ve had issues in the past with guys who would screw – we do plant-on backs – we’ll have guys that will put one screw in each side and think that’s good. We’ll have other guys who will put, you know, 35 screws in. Somewhere along the line I said, “OK, I’m going to put a hole where I want a screw, and you’re going to put a screw in it.”
So, we have that bit, which is the 3mm. We have a 3/8-inch compression bit. We have a 1/2-inch downcut and a 3/4 -inch downcut just for the Legrabox, because it’s got that thing that’s got to get routed, and the 3/4 does it in two passes. And an 8mm and 10mm. I’ve got all the places to hold them, so if we use it, I bought a drill for it so it’s perfect, and it’s not trying to wallow it out. We’ve also got a 35mm drill for doors.
Sampson: Do you have a system set up for tooling management as far as replacing or resharpening bits?
Dehmer: I don’t resharpen them. It seems like trying to figure out the offset when it changes would be more difficult than it’s worth. The 3/8 is the one we’ve clearly changed the most. We have a 3/16-inch that we use for our qualified dado, and that one gets changed out.
I got laughed at. I don’t know if it was on the (CMA) forum or just by somebody else on the board, but I sent a picture of it, and it was blue, of course. I asked, “How many sheets should I get out of this?” “I don’t know, 40; how many did you run?” “I don’t know, 120 or something.”
Sampson: That was going to be my next question: How do you determine when you change out your bits? When they turn blue? If it’s smoking?
Dehmer: Yeah, I just look at the quality of the cut. At a full unit, we start looking at what the quality of the cut looks like. I think we get 60 sheets usually. Because of our 5-1/2 horsepower spindle, we do two passes with the 3/8 bit. So, we’ll cut half of it, then we’ll go cut it again, but I can run it at 850 inches per minute with that 5-1/2 horsepower and it’s not that much slower than running it twice. I think it helps with parts moving, because it’s not trying to cut through the whole thing at once.
Sampson: Especially with the low vacuum (17-horsepower vacuum system) that you’re using.
Dehmer: It’s not low. (laughter) It works. Everybody says that! They assured me that it would work. I just figured I could buy another one if I needed it. But I also had a power problem still. With only 200 amps coming in, going up was just like, well, that’s where all the power is, in the vacuum.
Sampson: What is your advice for folks taking this leap to CNC routers? What do they need to do, that makes it more successful?
Dehmer: You can’t be ready enough for it. You place the order, and it’s going to take a while to get to you. Don’t spend all that time just doing your regular thing. Spend the time learning how to make that machine work, so that when it does get there, you’ve got a clue of what you’re doing. Like I said, we were way ahead of it, but I still spent a lot of time reading about it and reading forums.
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