Boreing Bars

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De Brun

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Aug 23, 2016
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I'm looking for a boreing bar that can cut a 9.5mm or 3/8" dia hole 50mm / 2" deep in Acrylic.

Does such a tool exist?
If not, what is the deepest boreing bar of that diameter available?
 
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I'm not familiar with "boring bar" as you describe it.
I agree with JimB, it sounds like you need a 3/8" standard drill bit.
If you drill on the lathe, you can put the whole very straight at whatever depth you need.
Gordon
 
I haven't used a boring bar (I don't have a metal lathe) but my go-to place for buying this kind of stuff is Enco (owned by MSC). Their site has a decent set of filters, it looks like for a bar capable of boring as small as 3/8" the maximum depth would be 1-7/8".

Link HERE

Other vendors might have one that can reach deeper, but it's a place to start.
 
Blind Hole I presume -- other wise I would drill and use a reamer (chucking reamers are in my tool box).

That is a lot of small bar hanging out there. I looked at Shars and for a 3/8 hole, they spec to 1 7/8 and I suspect the last half inch will be a bit challenging with chatter.
 
Boring bars are sized by the smallest hole that they can fit in. A boring bar is used to size a hole bored by a drill or reamer. I use a boring bar size the opening of kitless pen caps.

EBay, LMC.con are a good sources for boring bars.

Good luck.
 
They make them. But for that diameter/depth combo they get a bit pricey, like up to $100, but that is for one with index-able carbide inserts. You could try an end mill and use it like a boring bar, but for the depth would not be the easiest.
0.285 Inch Min Bore Diameter, 1/4 Inch Shank 82553447 - MSC is one, plus inserts. Carbide inserts may not be the best way to go for acrylics in that small diameter, though.
You could do this 3/8 Inch Shank Diameter, 3/16 to 3/8 Inch 08061509 - MSC and do a little extra clearance grinding on the one that reaches the farthest. Good luck!
 
Thanks for all the pointers, suppliers and links. I was going around in circles searching with no success; must not have been using the right key words?

I'm trying to machine a bore smooth enough to work with a piston and o-ring seal. A reamer might be a better option, but not as versatile.

Much appreciated:smile:.
 
Boring bars

I have a couple dozen boring bars , and I have live cutters set up on two of my lathes from live cutting threads to tapering and machining wood parts .

I grind mine some of my boring bars to make them the size I want ...and to make sure they are sharp and will not vibrate or chatter while cutting the wood .

All the holes I start are cut with a drill bit , I use a 5/16 3 fluted bit for the SS steel 3x10 pin I set in my pool cues wood to wood joints.
I am drilling setting a 3in stainless steel pin to less then 0.003 run out on every cue I make .. .

The drill bit is a 3 fluted carbide bit I put in my tail stock .
Very special bit , to do one pacific job .
No offence to anyone but a production goes if given the choice of drilling to size or using a boring bar and boring to size , I would go with the drill bit .

The one and only pen making arbor and collets kit I bought and the drill bit was bent ..

I believe the kit had been returned that I had got .

Straight Up I only buy certain drill bits for certain jobs..
The market is flooded with cheap POS drill bits .

I buy allot of my stuff from machine shop supply companies direct.
And I think my money goes farther that way and I get higher quality cutting bits and drill bits ...

I ended up buy three arbors to find one company the sells one that is actually runs true .
Getting the right tools for the job is extremely important when it comes to machining fine cuts .

PS good example of shooting wide open or the lenses lowest F stops, make for a extremely shallow or thin focal plane.
Everything before and behind the saw blade which by taking this photo I realized I had mounded the saw blade on backwards is out of focus .
Which isn't the normal if you are doing pen photography ( F 9 to F 11 )
I swear I can do some Dumb @ss stuff at times.

Machine safely ... because all these open saws a router bits and lathe spinning around make me nervous .

If its that big of a issue you could use a reamer ??????
 
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