Cheap&Easy Long Drill Bits

[Tundra Twin Track]

These are some long Drill Bit Extensions that are real easy to make.First drill desired size in small shaft then grind flat on one side of bit,slide bit in hole and crush shaft slightly to grip bit.The shaft will bend slightly after being crushed,grip in lathe and true it as pic shows.

[BCRider]

Other than a hammer and lots of swinging I don't have any way to force that heavy of a crimp. What are you using to do the crimp?

Although I don't have a good way to swage a solid crimp like you have this gave me an idea that might work for me and others without heavy presses or big enough hammers....

A saw cut across about a third of the extension rod's diameter should allow for peening the two sides of the cut down into a notch as shown in my sketch below. And for small drills in bigger rod that leaves the wall too thick a few licks with a round file and then a pin pinch or strong center punch to peen in the edges?

[Tundra Twin Track]

[QUOTE=BCRider;n1977077]Other than a hammer and lots of swinging I don't have any way to force that heavy of a crimp. What are you using to do the crimp?

Nothing special to crimp just a dull chisel and one hit with a hammer,the upper ones in pic is 1/4” shaft and lower is 3/8”.

[BCRider]

They looked bigger to me despite you including the ruler. Yep, I do got chisels! Thanks for the idea!

[J Tiers]

Do a substantiial flat.... I have some he-mount drills that are made that way, and they regularly spin in the holders. I don't use them anymore, I have a chuck that goes in the hex adapter.

The ones I have are not steel hex portions, which may have something to do with it.

[BCRider]

I've got a couple of sets of those hex shank drills too. Mine were steel hex sections. Likely softer steel. The crimps spun easily on the two or three bigger ones. The drills came out and were not grooved at all so the crimp didn't do much anyway. Needing to use one of them to make my life easier for an immediat job I filed a slight flat along the length of the shank, degreased the drill shank and hex holder and glued it with some thin CA. The light flat along the length being to aid with the thin CA wicking down into place and fully through the joint. It was the 3/16 size as I recall. It's still in one piece and hiding around here somewhere.

It is my luck with gluing that one which makes me think that I can get away with using the 680 in this case with no need for crimping then straightening.

[Tundra Twin Track]

I haven’t had any issues with them coming loose in shaft,I usually drill first hole slightly smaller than desired size then go in quickly with finish size to keep tolerance as close as possible.

[Paul Alciatore]

This looks like a good idea. I had two thoughts after reading the original post.

First, if the extension tends to bend when doing the crimp, why not do matching crimps on opposite sides. This has two advantages; first you will get twice the holding power so there is less of a chance of the bit spinning in the extension. And, of course, one crimp can compensate the bending from the other. Rolling it on a flat surface and some extra blows can easily straighten any bend that was introduced.

The second thought was that I could make some vise jaws for doing the crimps. I have made magnetic jaws for my bench vise ("Magnetic Vise Jaws", Machinist's Workshop, Jun-Jul 2017) bench vise and another pair would be easy. I would make them somewhat thick, perhaps 1/2" or 3/4", and have a hole in the center where some swagging dies could be mounted. Perhaps a set screw in each to retain those dies. A pair of dies could be made from something like 4140, pre-hardened, or just buy a couple of chisels and cut the tips off. I do have a 12 ton hydraulic press, but the bench vise should be more than enough for this and, with magnetic jaws, faster to use.

Of course, additional dies could be made for other purposes.

[J Tiers]

I've got a couple of sets of those hex shank drills too. Mine were steel hex sections. Likely softer steel. ..................

I looked at them again.... I DO have a set that the holders are NOT steel (and that set has always worked fine, it's larger drills and a bigger hex portion with a different chuck), but the ones that failed were a set that DOES have steel hex portions. Set came with the hex chuck.

So, the steel ones failed, and the pot metal ones always work fine. Go figure..........

[Dan Dubeau]

I've got a couple of sets of those hex shank drills too. Mine were steel hex sections. Likely softer steel. The crimps spun easily on the two or three bigger ones. The drills came out and were not grooved at all so the crimp didn't do much anyway. Needing to use one of them to make my life easier for an immediat job I filed a slight flat along the length of the shank, degreased the drill shank and hex holder and glued it with some thin CA. The light flat along the length being to aid with the thin CA wicking down into place and fully through the joint. It was the 3/16 size as I recall. It's still in one piece and hiding around here somewhere.

It is my luck with gluing that one which makes me think that I can get away with using the 680 in this case with no need for crimping then straightening.

I've made a few drill/reamer/tap extensions before using loctite 680. I used to solder them all the time, then tried 680 on a whim and it worked so I started using it. I think I've only had trouble with a tap I tried to extend with it. Either 6-32 or 8-32 maybe 10-24 can't remember. Just couldn't get it to hold up for more than a few holes so ended up soldering it for the remainder of the run.

I'll have to remember this other method TTT too, I like it.

The last extension I made a few months back was for a 5/16" counterbore. It was quick and dirty so I just drilled out a chunk of steel to fit the shank and hit it with the mig for a nice quick tack. It worked great, got me through the job, and it's nothing that can't be ground off with no ill effect to the tool, but I definitely angered the machinist gods on that one......

[gellfex]

Grandpa would just silver braze them in. I have a set of hex shanks bits and bitholder extensions up to 12". Handy for drilling and driving. If it's not a fractional I have both a 1/4" chuck with hex shank and a set of 6 hex collet holders that run down to pin chuck size. This group solves most issues.

[Mr Fixit]

I made a couple a few years ago for a deep hole 12" that I needed to drill in some steel. I did as Paul A. suggested and ground 2 flats 180* from each other on the drill bits and then put 1/8" drill rod pieces in the bench vise with duct tape and pressed the shafts from both sides, worked like a champ and as others said there still in the shop waiting for the next job..

TX
Mr fixit for the family
Chris

[Mcgyver]

I see drill extensions like that in tool & die guy's boxes, to reach into a die I suppose. However every time I've need a long drill its been for a long hole....so the extension can't be larger than the drill. I've always silver solder an extension on, simple butt joint, and haven't had one fail yet

[mochinist]

Grandpa would just silver braze them in. I have a set of hex shanks bits and bitholder extensions up to 12". Handy for drilling and driving. If it's not a fractional I have both a 1/4" chuck with hex shank and a set of 6 hex collet holders that run down to pin chuck size. This group solves most issues.

not a grandpa yet but I used to do this and braze them in also. Nowadays I just use 609 loctite

[Tundra Twin Track]

I posted about this home brew style of drill bit extensions after seeing BC Rider ER 11 collet extension Post,unless I missed it no one mentioned this simple solution.Some good ideas mentioned here on fastening drill bit to extension different styles of compression,soldering,brazing&loctite.