# Boring Bar Setup That I Can Use In My Mt#3 And My R8 Mills



## motofool33 (Apr 10, 2016)

Hello i am looking to get a boring bar that i could use on either my mills or on my Lathe. 

i cant find any adapters that go from MT3 to R8, but i can find r8 to MT3 but they are very long and you lose alot of z axis travel.  

Is there a setup that has changeable tapers?


----------



## awander (Apr 10, 2016)

There are boring heads that have interchangeable shanks-I have one, for instance, that has MT3, R8 & B&S9 shanks. Another with MT4 and R8 shanks.

What do you want to do with the boring head on the lathe? It's probably just easier to hold a boring bar direct, on the toolpost, rather than try to use a boring head in the tailstock....or are you thinking of installing the boring head in the lathe spindle?


----------



## motofool33 (Apr 10, 2016)

awander said:


> There are boring heads that have interchangeable shanks-I have one, for instance, that has MT3, R8 & B&S9 shanks. Another with MT4 and R8 shanks.
> 
> What do you want to do with the boring head on the lathe? It's probably just easier to hold a boring bar direct, on the toolpost, rather than try to use a boring head in the tailstock....or are you thinking of installing the boring head in the lathe spindle?


Looking to use it for making key ways possibly 

Sent from my SAMSUNG-SM-G900A using Tapatalk


----------



## awander (Apr 10, 2016)

motofool33 said:


> Looking to use it for making key ways possibly
> 
> Sent from my SAMSUNG-SM-G900A using Tapatalk



OK, well, my questions above still stand, i think.

How are you envisioning using the boring head? Easiest way is to grip the work in your lathe chuck, and use a boring bar on the toolpost to cut your keyway.

I still don't see why you need a boring head for that. The only thing I can envision is if you plan to mount he work on the cross-slide, and mount the boring head in the spindle or the tailstock. But even then, you wouldn't need the adjustability of a boring head.....


----------



## motofool33 (Apr 10, 2016)

Well the one video i saw using a boring bar to cut a key way was being held by the tool holder. 

i was just thinking of all scenarios if i had to reach deep down in something to bore it would be nice if i bought a setup that fit in the tailstock. but if thats not normal practice i can just buy a boring bar that doesn't fit i suppose.

right now i dont have a way to hold the boring bar in my tool post on the lathe either.


----------



## CraigB1960 (Apr 10, 2016)

MT3 taper works in friction mode, whereas an R8 taper needs a drawbar.  Because of this, I've never seen a MT3 to R8 adapter and most likely will never...just R8 to MT3


----------



## Bob Korves (Apr 10, 2016)

Just grind a tool, put it in the tool holder, and presto, you have turned your lathe into a shaper.  Spindle locked, tool that cuts on the push stroke, and move the carriage back and forth manually while advancing the tool with the cross slide.  Take about .001" per pass.  Low tech, controllable, adaptable...

Edit:  A modified HSS lathe tool works much better than a boring bar.


----------



## Steve Shannon (Apr 11, 2016)

Brino,
I wish I could like that twice!


 Steve Shannon


----------



## Bob Korves (Apr 11, 2016)

Steve Shannon said:


> Brino,
> I wish I could like that twice!
> 
> 
> Steve Shannon


Not Brino, Steve, but thanks anyway...   8^)


----------



## Steve Shannon (Apr 11, 2016)

I apologize! But I still wish I could give it two thumbs up! 


 Steve Shannon, P.E.


----------



## BGHansen (Apr 14, 2016)

Pretty sure there's a tubalcain video on the broaching technique on the lathe.

Bruce


----------



## CraigB1960 (Apr 14, 2016)

BGHansen said:


> Pretty sure there's a tubalcain video on the broaching technique on the lathe.
> 
> Bruce


There is.  Using a lathe for broaching is very similar to broaching with an E-Head shaper mounted to a bridgeport.  Just takes a lot longer and it is all manual.  It works fine if you broach infrequently, but it takes a lot of time and effort.

If you are going to broach a lot, there is no substitute to buying a broach set and using an arbor or hydraulic press.  Or a shaper!


----------



## Steve-626 (Apr 16, 2016)

CraigB1960 said:


> MT3 taper works in friction mode, whereas an R8 taper needs a drawbar.  Because of this, I've never seen a MT3 to R8 adapter and most likely will never...just R8 to MT3



The MT3 tapers that are in the mill drills have a threaded end for a drawbar

3/8" -16


----------



## CraigB1960 (Apr 16, 2016)

Steve-626 said:


> The MT3 tapers that are in the mill drills have a threaded end for a drawbar
> 
> 3/8" -16



That is a specialized application and not part of the morse taper standard.  Whereas the R8's standard has the drawbar as it's standard.

My point was Morse Taper is designed as a friction lock, with or without a tang...the R8 taper requires a drawbar.  The R8 could not physically fit inside a MT3 taper, so it would be very long and does require a drawbar, so changing tools would be tedious.

There's a reason we don't see a MT3 to R8 holder.


----------



## Wreck™Wreck (Apr 24, 2016)

CraigB1960 said:


> There is.  Using a lathe for broaching is very similar to broaching with an E-Head shaper mounted to a bridgeport.  Just takes a lot longer and it is all manual.  It works fine if you broach infrequently, but it takes a lot of time and effort.
> 
> If you are going to broach a lot, there is no substitute to buying a broach set and using an arbor or hydraulic press.  Or a shaper!


You can't push or pull a broach through a blind hole.


----------



## CraigB1960 (Apr 24, 2016)

Wreck™Wreck said:


> You can't push or pull a broach through a blind hole.



The key phase I used was "broach a lot"!

If I was going to do a lot (of blind hole keyway cutting) I would use sinker EDM or a product from this company: http://www.keyseaters.com/index.html

I have had faster results using an end mill to cut the keyway slot and than final  shaping with a file than using a lathe with a sharp bit to cut a keyway.


----------



## Wreck™Wreck (Apr 24, 2016)

I have had to resort to the lathe once or twice in the past and it is a tedious process at best, a sinker EDM is not a hobbyist friendly process however.


----------



## CraigB1960 (Apr 24, 2016)

Wreck™Wreck said:


> I have had to resort to the lathe once or twice in the past and it is a tedious process at best, a sinker EDM is not a hobbyist friendly process however.



LOL, never said it was...but as a hobbyist and I had "a lot" of blind keyways to do...I would outsource it to a shop that did.  There are folks here that might benefit with that knowledge...only reason I threw it out.

Several of my hobby projects grew into products that I market.  I certainly don't machine those parts anymore...I've outsourced it due to volume.


----------

