Drilling technique

In one of my classes we're reflooring a trailer. Lucky me I get to
drill all the holes. #16 drill bit. 2" boards on top of steel frame
members about 1/8" thick. I'll drill the wood, clear the chips, then go
through and dill the frame. So far I've been sticking with relatively
low speed and high pressure. Is that the best way to do it, or should I
trade off for more speed/less pressure? A HSS bit will go about 40-50
holes before getting uselessly dull, but occasionally I'll strike a weld
over and old hole and that'll significantly shorten the drill's life
Is 40-50 holes expected? Anything I can do about the welds short of
dumb luck?
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Try high speed (around 2500 rpm) and enough pressure that the drill is cutting continuously rather than just spinning against the metal. You should get a lot more than 50 holes out of a bit unless you hit a weld.
Reply to
Steve Dunbar
My drilling technique is this:
I watch the cuttings. I NEVER use high speed. As long as I can see cuttings, I just keep up the pressure. Most of my drilling is at medium speed or less. I think that when I am cutting at my best speed/pressure combination, I see spiral cuttings.
Works for me, anyway.
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When you're reflooring a trailer (or truck body) the first thing to do is grind all the rust off the top of the cross member. Don't know why, but drilling through rust will eat the day lights out of the drill bits. After you have the cross member clean, the flooring laid out, start making holes and install the floor. I used to own a trucking company and we replaced and patched floors on a regular basis. It didn't matter whether we we installing apitong on flatbeds and lowboys or laminated oak in vans, be prepared to sharpen or change out the drill bits regularly. I used to buy good bits and the if we "only" used 8 or 10 to do a floor I felt lucky. It didn't seem to matter whether we used 1/2" Milwaukee hole shooters or CP air drill, we got about the same mileage out of a bit. Greg B.B. wrote:> In one of my classes we're reflooring a trailer. Lucky me I get to
Reply to
Greg Postma
Unfortunately, I can't see the cuttings because I have a plank of wood in the way. Upon reading more I think I'll stick with the way I've been doing it.
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How many trailers are you doing? A single trailer? If so, you've probably found the best method already except for maybe the addition of some cutting fluid of some sort if you can get away with it...
If you have lots of trailers to do, I have an comparitively expensive, but proven method that folks use. Maybe $3000 minimum depending on what you actually need to do.
I just talked to a fellow that does the full length trailer boards all at the same time across the short way, moves over X number of inches and does the next row... Finishes a whole trailer with aluminum or wood planks in less than an hour from what I can tell... Like I said, it depends on your actual need.
Regards, Joe Agro, Jr. (800) 871-5022
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Joe AutoDrill
Drill all of the wood holes in a piece of lumber, making sure that you dimple the frame underneath. Then slide the wood aside and drill the metal, using lubricant andd a fair bit of pressure. You want to use enough pressure at a moderate speed so that you get nice curls from the metal rather than dust. Some steels do tend to work harden and that is made worse by not drilling the hole with enough metal removal at a turn of the drill. You also get to redrill any holes that hit welds without problems. Redrilling the wood to a #3 drill and pounding in a 1/4" dowel will fill those misdrills.
-- Why isn't there an Ozone Hole at the NORTH Pole?
Reply to
Bob May
I'm afraid I can't do it that way. The frame is distorted, so we have to clamp a section, drill & screw it down, move the clamps over, and repeat. There's no way I could talk everyone into letting me go over everything twice, clamping everything along the way. I'll just continue the way I have been (low speed/high pressure) and see if I can get them to let me keep the drill doctor near the trailer for a day.
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