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bigloudvtwin

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#1
I'm going to be chucking uo a piece of steel round stock 4" dia x 10" long. I want to bore into it approx. 8" deep. Final bore size to be 1.675 (golf ball interference fit). I don't have any drill bits this long to make a pilot hole for bar clearance.
Can I do the entire hole with a boring bar from a flush face to final cut?
I can either buy a bar or build a tool holder for a smaller bar. Just need the right angle on the cutting face. My experience with cutting angles is a trial and no chatter/galling error process.
Thanks
 

Richard King 2

Master Machine Tool Rebuilder & Instructor
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#2
What kind and size lathe do you own? What type of tool holder? Do you have a boring bar? What size taper in your tail stock ?

Have a steady rest? It's hard to help with out know these things..... Rich
 

RJSakowski

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#3
I'm going to be chucking uo a piece of steel round stock 4" dia x 10" long. I want to bore into it approx. 8" deep. Final bore size to be 1.675 (golf ball interference fit). I don't have any drill bits this long to make a pilot hole for bar clearance.
Can I do the entire hole with a boring bar from a flush face to final cut?
I can either buy a bar or build a tool holder for a smaller bar. Just need the right angle on the cutting face. My experience with cutting angles is a trial and no chatter/galling error process.
Thanks
When I need an extra long drill bit, I make them. Turn down the shank of the drill bit to around 2/3rds the diameter of the drill. Select a rod equal to or smaller than the diameter of the drill and bore a socket to fit the turned down shank. Insert the drill into the socket and fix by brazing, silver solder or Super Glue.

I would make the hole starting with a small diameter pilot and stepping up the size until it was convenient to bore with the boring bar.

You can bore a hole without a pilot with the right shaped bit. It is more tedious due to the zero radius cutting.
 

Asm109

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#5
You need a 5 inch long drill. Drill from each end then use a boring bar from one end to clean up the hole and make it one size from end to end.
 

BtoVin83

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#6
IMHO trying to do it straight away with a boring bar will give you nothing but grief. Three choices come to mind, make a longer drill as RJ suggested (I always piloted them together and silver soldered), use tubing and make a breech plug, make/buy a spade drill. Spade drills work really well we had one 4 feet long.
 

chips&more

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#7
Making a golf ball cannon are you? To just make this a boring bar operation would be VERY challenging. I would pre-drill then bore to size…Dave
 

RJSakowski

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#8
You need a 5 inch long drill. Drill from each end then use a boring bar from one end to clean up the hole and make it one size from end to end.
I believe the OP stated that he wanted to bore a hole 8" deep in a 10" bar, the implication being that it is a blind hole.
If it were a through hole, I would definitely drill from either end.
 
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