Best way to put a deep Blind hole in something.

[jim18655]

Could you drill from both ends and then close one end?

 

[kvt]

Thanks for the responses one and all, I would be afraid to use super glue as would be afraid that it would turn loose and get jammed in the hole some how. the old adage something about if I did not have bad luck I would have no luck at all. Well that is me. So bad my wife and I both entered a drawing. one other person entered, and we did not win.
My brazing is prob just about as bad as my welding at this point. I would have to go lease a O2 tank just to fire up the torch, and use propane. I have been out of doing thing so long it is the pits. My welder even needs the carb and fuel pump rebuilt.
Ken If I do not figure something out this week end will send you a PM.

 

[rgray]

I use a gun drill for such things. Drills straight and the large bit will follow the hole.
I usually use 5/16 or 3/8.
http://www.ebay.com/itm/Eldorado-Gu...875693?hash=item43ea0306ad:g:wFsAAOSwG-1Wx2bw

 

[mikey]

Thanks for the responses one and all, I would be afraid to use super glue as would be afraid that it would turn loose and get jammed in the hole some how. the old adage something about if I did not have bad luck I would have no luck at all. Well that is me. So bad my wife and I both entered a drawing. one other person entered, and we did not win.
My brazing is prob just about as bad as my welding at this point. I would have to go lease a O2 tank just to fire up the torch, and use propane. I have been out of doing thing so long it is the pits. My welder even needs the carb and fuel pump rebuilt.
Ken If I do not figure something out this week end will send you a PM.

You can always use soft silver solder and heat with a propane torch to join the drill to the extension. It would be more than strong enough for that job.

 

[tq60]

Here you go...
Having a shaft rotate in this hole means cut needs to be clean.

First get the hf set as they are decent and cheap.

Please note...Do NOT step up as it will cut off center and chip the drill.

Pilot drill with a 1/4 bit and this can be as a single shot or rotating back and forth.

1/4 X 12 are not too expensive and very handy to have.

Get a chunk of round larger than 3/4 by 2 inches long and drill 1/2 hole through it.

Drill and tap 2 or 4 set screws to secure the drill and 1/2 round extension.

Grind a flat or drill a pilot hole in side of extension and secure the above part to extension and place in lathe holding by extension and turn to 0.745 OD.

The bit should have 3 flats on tge shank or make a pilot hole as in extension.

Make part.
Start with stock an inch longer than needed and face off.

Center drill then drill in pilot with 1/4 standard length.

Now use the hf drills and drill in next smaller than 3/4 a depth of 2 inches.

Place boring bar in and bore out hole until 3/4 but just fits.

This insures it is in center and straight.

If you can drill deeper in step above.

Now the hole you bored will he a guide to keep drill on center and straight.

You will need to be sure to keep the 1/4 inch hole ahead of the larger one and use it to determine depth as the big one will change when it bottoms.

Look at the large bit and notice the flutes STOP.

you will need to operate your lathe in slowest speed with heavy pressure and lots of oil and peck the cut.

The coupler you made will also support the drill as it goes into the hole.

Go slow and it should have a clean cut.

You can polish it with a wheel cylinder hone if needed

Sent from my SAMSUNG-SGH-I337Z using Tapatalk

 

[Wreck™Wreck]

One of this mornings jobs, 7/16" hole through an 8" length. Spot drilled then went all the way through with a 12" long 7/16" drill, if I had stopped at 7 3/4 it would have been a blind hole.
2" OD 4140 annealed with a 3/4-14 British Standard Pipe Parallel external thread on one end and an internal thread on the other just to make it more fun. They are a 55 Deg. Whitworth thread form for which we had exactly one insert.
Some species of hydraulic adapter.

You should have no problem drilling 8" deep with a suitable length drill. If you require a more accurate sized hole drill slightly small then ream.

 

[Plum Creek]

I have a torch and brazing tip at the shop near Kyle that your welcome to use if you decide to solder or braze.

 

[Charles Spencer]

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.
View attachment 233699

Good idea. Combined with grinding a flat and using set screws I think it would be pretty solid.