Here's my situation. I am making some bumpers(10 to be exact) and I need to make some 1/2" square holes in them. I've been drilling 1/2" holes, then using a die grinder and file to make them square. With 6 holes per bumper, thats 60 holes, and it is going to take a long time to do them all. So, is there a faster way to do it? I have a small press avalible to me. Is there a tool I can buy or make that will make things quicker/easier/more repeatable? Thanks
Maybe try making a square punch from some 1/2" hard keystock and some sort of dye underneath and use your press. Just a thought. Then again maybe theres a machine tool supply that offers such a tool. Bob
Hey.. Years ago ( late 60s) I work'n in a machine shop. We used to drill (yes drill ) square holes. The drill chuck was a floater, you used a hard'n steel template. A special drill (look'd like a reammer) was used. Work'd out well most of time. Know this isn't any big help but wanted to tell ya there is a way. Maybe a machine shop can lead you in a viable direction. Maybe there is a machist on board that can help ya Pontiac Slim
They make square punches for punch presses. A pain in the *** to get them lined up right, but once you do they beat the hell out of drilling and diegrinding...
That square hole drill is a Watts Drill. I have used them before, they are designed to make very accurate holes and are difficult to use, you really need a milling machine with a power feed on it. Chip the drill and you have to send it back to the factory to have it reground if you do not have a tool and cutter grinder. Did I mention they are expensive. Find a fab shop with an iron worker and see if they have a set of 1/2" square punches. This is the easiest way. A set punches might set you back $100 or so if they do not have a set.
the iron worker is your best bet. we have one here with the square punches. just start calling all your welding shops. also could try vo-tec schools in your area with a welding or machining cl***. good luck
get a punch called a greenlee punch here are some on ebay. http://search.ebay.com/search/search.dll?sofocus=bs&sbrftog=1&from=R10&sa***le=greenlee+punch&sacat=-1%26catref%3DC6&bs=Search&fsop=1%26fsoo%3D1&coaction=compare&copagenum=1&coentrypage=search&fgtp=&sargn=-1%26saslc%3D2&sadis=200&fpos=89436&ftrt=1&ftrv=1&saprclo=&saprchi=
I'm ***uming square for Carriage bolt shoulders? Why don't you smooth your bumper now? Drill 1/2 rounds. Then cut your 1/2 allthread and weld the one end in. Grind on the front to smooth it and be Kustom! A lot of guys with Ironworkers usually have die sets with squares in them. That you just punch out.
Just dealt with the same problem. Drilling 1/2" holes and squaring it is a pain in the ***. I decided to drill a 11/16" hole, wich is just enough for the carriage bolt NOT to fit, with a whack of the hammer it was a done deal, the nut on the other end did the rest.
You can get a 1/2" square broach,drill the pilot hole and use the broach in a press. One p***,done. But the broaches are not cheap. Check Travers.com , Mcmaster.com ,Enco,KBC,or MSC for broaches.
I would, and we do make some in that style, but these are stock repro 55 T-bird bumpers I'm making, and restorers need their carrage bolts I'd have to measure, but I think they are thicker than 10 guage, and they are a fairly high carbon steel, not mild steel. Plus, once I get the holes made, they'll be chromed. Thanks all for the info.
Could you make a square jig (or several) for a Plasma cutter that would allow you to cut the holes to the exact shape, size and location?
No, and no. 1st, due to the initial stamping, and type of steel, their temper is close to that of spring steel. Heat would eliminate that around the bolt holes, and might possible cause warping. 2nd, I actually had that thought, and like the idea, but we don't have a plasma cutter, and again with the heat thing.
Cha-ching! Wow... McMaster's wants $168.18 for a half inch square broach. http://www.mcmaster.com/nav/enter.asp?pagenum=2398 .
Problem with that is the cost. We had a run done that were laser cut(very little heat transfer), but because of the curvature of the bumper, it needed to b a 6 axis machineeek: ). The setup cost was crazy high, and for a short run like this of only 10, it's cheaper to pay me to file holes than have them cut. Waterjet would run into the same setup cost issues. Good thought though, and I'll keep it in mind for if/when we need to do a large run. I think we need somewhere around 50 before it's more cost effective to have them lasered. I like that broach though. I'm going to have to suggest it.
Well, the obvious answer to your dilemma is to charge more! Seriously though, could you use a jigsaw with a metal cutting blade to square off the holes? Might not be any quicker than grinding, but it's a thought. Let us know what you end up doing, I'm sure someone else will need to do this in the future... Ben
Find a local wroughtiron fence shop, they use 1/2" square stock for fence pickets and are usually have an ironworker set up for punching the rails....my $0.02.....Stan
Got a big metal fabricating/machine shop nearby? There was one in the Central California town I moved from that had a laser cutter. Big table, computer driven, very,very small kerf after the cut. It might help if you made a support jig for it. I wonder too if drilling four 1/6" - 3/32" holes at the outer corners prior to drilling the 1/2" hole would make life easier if you end up grinding and filing the hole to shape
That is probably the best out of the box thinking I've heard on here in a while. That is absolutely right, so obvious, but I'd a never thought about it.
Thanks all for the suggestions. I'm going to look into the fence thing monday, if that doesnt pan out, we're going to try the broach that 29MurrayTub linked. In the mean time, I drilled, die grinded, and hand filed all of them that we had today(not an experience that I'd want to do again)
This hand punch has 1/2" square in it. Don't know if it suits your need. Probably will do 1/4" steel. Not for sale, but maybe you can locate a similar one.
I punched a dozen square holes in 3/16 mild steel for 5/16 carriage bolts using a broach made from a 5/16 square tool bit from the lathe. Used a 5/16 8 point socket to hold it, and another socket to back it up under the press. Ground the end of the tool round to fit a 5/16 pilot hole. Pretty crude, and required resharpening the tool a couple of times, but quick and cheap. YMMV. Jerry
Unkl Ian's got the answer, use it in an arbor press. I've used them, it will give a clean square hole. The punch idea is OK, but may leave a flat area around the hole, if there is a crown where you punch it. Most of the fence guys in this area are rude and crude, their equipment is the same, so their punches are real dull. Dull punch = ugly hole.
If you can't find an ironworker with a square punch here's an idea: Drill four small holes, one for each corner, then drill the 1/2" hole. The burrs that are left could easily be fixed with a square punch, file, etc. I'd look into using a plasma cutter. They are so fast heat isn't a big problem. I've cut steel that was galvanized and painted with one -- the paint only burns about 1/8" from the cut. Build a jig to guide the cutter tip and it would make quick work of the hole and the edges should be smooth enough to leave. There may be a place that rents one near you. Good luck!
EDM is always another option. A machine shop should be able to do it for you, but once again it's a costly setup.
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