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drill bits

Started by coxy, October 31, 2014, 06:26:09 AM

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scsmith42

Quote from: elk42 on November 02, 2014, 11:51:26 AM
IT could be a Hougen Rotabroach® Annular Cutters, Look it up.

That was my thought as well.

For smaller holes, I prefer to purchase machinist grade bits.  For years I bought Butterfield (and they are great bits), then I moved to Magnum bits mfg by Norseman here in the US.  These bits will drill both spring steel as well as many grades of stainless steel.

A Darex Drill Doctor is a great tool for most folks to keep the bits sharp.

I have a Hougen Rotabroach magnetic drill, and it is a great tool for drilling larger holes or drilling holes through thick metal. 

One thing to keep in mind is bit speed.  Basically the larger the diameter of bit, the slower you want to turn it in order to keep from burning the tip.
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Al_Smith

--conversely the opposite is true if drilling wires sized holes like with a #27 bit .Going too slow is a sure way to break a bit .

Holes are  holes .For those not so well equipted as some of us a hole saw could be an option.They come in just about every size and are easy to use with just a hand held drill motor .Use plenty of oil .

coxy

north river energy thanks for the link going to give them a call   thanks every one for the help  :)

36 coupe

Step drilling is a sure way to break the corners off a drill.Friend borrowed my 5/8 bit and broke the end off trying to open up a 1/2 inch hole in a trailer hitch.The drill caught and broke the drill about 3/4 from the point.I found a reference to step drilling in a 1940s manual.A writer copied the info word for word in a metal working book later on.You will break drills step drilling.Big drills need a small starter hole to get the cutting edge of the big drill started.Ive been sharpening and using drills since the early 50s.I will not do step drilling.Friend replaced the drill bit,If I had known he was going to step drill a 1/2 inch hole with a 5/8 bit I would not have loaned him the drill bit.The corners of the cutting edge dug in and snapped the bit.

Al_Smith

Perhaps your buddy was a clutz .Just as general information the standard method of drilling holes in cast iron engine blocks was a three drill process followed by a finish bore reamer and a tapped hole Must have worked because it's still done that way .

I'd also speculate your bud was using a half inch hand held drill motor and a turned shank bit .More than likely went off kelter drilling the hole .With a drill press,mag drill or milling machine that doesn't happen unless you forget to clamp down the work piece .T'aint what you do 'tis how it's done  ;)

North River Energy

Coxy,
That link is for the bit in the photo.  Fairly certain I purchased that from Travers Tool co. a number of years back, but they (and MSC Industrial) now carry the Hougen product line. 

More or less the same thing, give or take a few dollars.  They don't give those away, but the savings in time and hassle are totally worth it if you have the need for the holes and a means to drive the cutter.

Al, thanks for trying on the photos.  I was ' conducting a job interview' with a large Cincinnati-Gilbert Saturday morning, and your mention of 'radial drill' and '5 MT' simply added heat to the case of iron fever.

Step drilling per se isn't the problem, it's how the cutting edge is loaded that leads to breakage/dulling.

Al_Smith

Well you can regrind the outer edge of the drill flukes to alleviate the possibilties of breaking them .

I just didn't want to get carried away too much in the conversation .There's a trick to everything ya know . ;)

As far as a big radial they aren't that hard to find .Fact the one I have was given to me by a buddy .He only had 240 three phase and this one uses a straight wired 480 volt .Not a problem for me .If I had enough transformers ,a good set of diodes and a big enough capacitor I could build a bolt of lightning . ;D

Keep in mind old Ron is a junk yard dawg like myself .I gave him a Vickers hydraulic unit ,60 gallon tank,7.5 HP to run his 200 ton press .We kind of help each other out from time to time .Junk yard dawgs you know run in packs ,it's an undeclared fraternal brother hood .

brianb88

As someone else mentioned the annular cutter bits are very good for use in a magnetic drill.  I don't know what the best brand is but we generally use FMT production and they work well if you keep them well lubricated.  They are pretty salty though.  I bought 6 - 1 5/8" diameter x 2" length bits for $1,125.44.  Did I mention not to forget to lubricate liberally?   
Measure twice, cut once

hackberry jake

I have a few solid carbide drill bits and they work great! You have to run them really slow breaking through the back side of the hole or they will shatter. They cut great for a loooong time if you're careful with them.
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Al_Smith

I think Milwaukee calls them a "slugger bit " .Pricey but the cats meow on a mag drill .

Actually a mag drill in itself is the cats meow .Without it I cannot imagine drilling 3/4"-13/16"  holes in structural steel by swinging  around an I beam into a radial or stationary drill press on the end of a chain fall.You darn sure aren't going to do it with a 1/2" drill motor and turned shank bits .

Al_Smith

Since it's been mentioned I also have a bunch of solid carbide bits .They all came from the scrap tubs at work .Once they get too short for the CNC machines they get discarded .

About the only thing I use them for is drilling chainsaw bars and drilling out grade 8 bolts .A grade 8 is so hard a standard high speed steel bit won't even touch them .If it does it only makes to bolt get harder from the heat .

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