Gallery, Projects and General > How do I??
long hole with a short drill?
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redhunter350:
Hi Skyrocket, Consider purchasing a Morse taper extension then machine down part of the female end so it is just under the drill size you are using. These are about £10 from Arc euro trade, don't know how hard they are but probably machinable with carbide or maybe HSS. You will need to weigh up the sizes to evaluate whether this will work but I have seen it done. You may also be able to use the same socket for your pilot drill as well -- depends on the MT size of both drills

No need to grind the flutes just keep clearing the drill as you proceed to depth.

If you drill does not have enough travel I would consider doing it in the lathe with a 4 jaw chuck.

Good luck with your project
John
 
BaronJ:

--- Quote from: Skyrocket on February 09, 2014, 05:34:08 PM ---hi chaps, yes another video :wack: , can anybody suggest a way of drilling a deep hole in aluminium with the drill bit I have? regards chris

--- End quote ---


Hi Chris,


The easy way as you suggest would be to mill a suitable channel in each piece of bar.
Seeing that you have a lathe and a mill,  why not make a milling cutter ?


This is how I would do it.  Obtain a short length of steel bar of a suitable diameter or a little larger.  Turn it down to the correct diameter.  Part off a disc, say 3 or 4 mm thick.  Make a spindle from a bit of 1/2" rod and mill a slot in the end to take the disc. Braze or weld the disc into the end.  Now grind a relief on opposite edges, like a spade drill, so that it will clear the work when cutting.  Heat the disc up to red heat plunge into a tin with some sugar in it.  Repeat, then dunk in water.  This will harden it.  Use like an end mill with plenty of lube.


The other way would be to put it in the four jaw on the lathe and use jubilee clips to keep it together. True it up and then drill a pilot hole as deep as you can and then use the big drill.  You will still need to use lube.  I use paraffin for alloy.


HTH.





geoff_p:
Jonny has the answer if you combine his ideas:  Round-nose end-mill along each half, then clamp them together on your lathe saddle and open-up to size with a boring-bar between centres. 

If your lathe doesn't have sufficient between-centres (a tad over twice the length of the workpiece), then put the job on the saddle and the tool in a 4-jaw - in the video you seemed to suggest you have a long-enough boring bar.
Geoff,
Thailand
BillTodd:
The simplest method would be to drill from both ends.However, a cheap drill press is unlikely to drill straight or square.

You could probably drill and bore on a lathe  by clamping the pieces to the cross slide and line boring (I ve used this method to make long semi circular channels for a pipe bender). You'll need a lathe with twice the part length between centres.

Bill
BaronJ:

--- Quote from: Baron on March 30, 2014, 06:18:06 PM ---
Hi Chris,


The easy way as you suggest would be to mill a suitable channel in each piece of bar.
Seeing that you have a lathe and a mill,  why not make a milling cutter ?


This is how I would do it.  Obtain a short length of steel bar of a suitable diameter or a little larger.  Turn it down to the correct diameter.  Part off a disc, say 3 or 4 mm thick.  Make a spindle from a bit of 1/2" rod and mill a slot in the end to take the disc. Braze or weld the disc into the end.  Now grind a relief on opposite edges, like a spade drill, so that it will clear the work when cutting.  Heat the disc up to red heat plunge into a tin with some sugar in it.  Repeat, then dunk in water.  This will harden it.  Use like an end mill with plenty of lube.


The other way would be to put it in the four jaw on the lathe and use jubilee clips to keep it together. True it up and then drill a pilot hole as deep as you can and then use the big drill.  You will still need to use lube.  I use paraffin for alloy.


HTH.

--- End quote ---


Attached drawing.  May help !



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