Best way to put a deep Blind hole in something.

[kvt]

Ok, another question from a self taught hobby person. It is probably simple but.
I have a large piece of steel round that I need to put about a 10 inch deep blind hole in. But do not have a drill bit long enough, and large enough to get hole started to even bore it out. The hole I need will be approx. 10 inch deep, and just over 3/4 inch 0.750 in dia, with a steel ball in the end that another shaft just under the 0.750 size would ride against. (other though was a thrust bearing rather than the steel ball). Any ideas. I know I could go purchase a long drill bit, but have not found one that is about the right length that I can get/afford at present. Any ideas/suggestions would be greatly appreciated.

 

[markba633csi]

Probably would need to make an extended drill bit by welding a shaft onto a standard size bit. It's commonly done.
Mark S.

 

[EmilioG]

Extended length drills past 9" cost about $100 from McMaster Carr. Maybe an extension holder can be used to reach the 12" depth with a long drill.

 

[kvt]

Mark, I would have to be a better welder than I currently do. have not done much in years, thus not very good at it any more. But if it comes down to it I may give it a try.
EmilioG, I though of an extender, but all the ones I have seen are for 1/4 inch stuff not something like a 1/2 inch shank on a large drill bit.

 

[Bob Korves]

Here are pics of a couple that have been brazed together. They need to be jigged in a straight line before joining them, and it is a good idea for the added shank to be a little smaller diameter than the drill.

 

[Bob Korves]

For your job I would get a 3/4" Silver and Deming drill (1/2" shank) and use a 5/8" extension to drive it. The extension could be drilled to fit the 1/2" shank and then the drill brazed into it, or instead could be connected with a 5/8-1/2" sleeve brazed on to a 1/2" extension and the drill.

 

[4GSR]

Ken,

I have a selection of extra length drill bits here at my place. Some are straight shank, some have either a 2 or 3 Morse taper shank. If you're interested send me a PM and I'll make arrangements to get one to you.

Ken

 

[RJSakowski]

Ok, another question from a self taught hobby person. It is probably simple but.
I have a large piece of steel round that I need to put about a 10 inch deep blind hole in. But do not have a drill bit long enough, and large enough to get hole started to even bore it out. The hole I need will be approx. 10 inch deep, and just over 3/4 inch 0.750 in dia, with a steel ball in the end that another shaft just under the 0.750 size would ride against. (other though was a thrust bearing rather than the steel ball). Any ideas. I know I could go purchase a long drill bit, but have not found one that is about the right length that I can get/afford at present. Any ideas/suggestions would be greatly appreciated.

I have made numerous extension bits by turning down the shank of a drill bit and boring a socket into the end of an appropriately sized piece of round stock. For securing the assembly, I have used a number of techniques including brazing, and superglue. I have most recently resorted to the superglue because of convenience and have never had one let go. The largest extension that I have made was a three foot extension for a 1-1/16" S & D drill bit. I made the drill by making a coupling from 3/8" black pipe and used superglue to fasten a 3' length of 1/2" SS rod and the drill bit together. In spite of the fact that I had interrupted cuts ( I was drilling through 3" steel channel at an angle), the drill held together with no sign of failure.

 

[RJSakowski]

I would add, that given the task the OP is attempting, I wouldn't use super glue for fastening. Drilling a deep hole like that will generate a lot of heat which will soften a superglue bond. Pinning or brazing would be the options that I would consider.

 

[Jimsehr]

You can buy a 8 piece set of S&D type drills from Harbor Freight tools for $34.99.
They have half inch shanks. You can then take a piece of stock and drill the end about an inch or more deep a few thousands smaller then half inch shank and then heat stock cherry red and insert drill shank and let it shrink fit to S&D drill of size you need. If you don't get a good fit pin it. You then have a long drill and 7 more for 35 bucks.
Jimsehr