R8 extension? Do they exist?
 

Got a boring job to do in the mill. Big ugly
casting, and I need to reach about 7" down
through a 3.25" hole. Problem is that my ram is
3.5". I would like to use my boring head
rather than a fly cutter. Does anybody make a
R8 male by R8 female extension? Around
5" would do it.

Thanks,

Bill

R8 extension? Do they exist?
 

On 2008-06-11, BillM wrote:
Got a boring job to do in the mill. Big ugly
casting, and I need to reach about 7" down
through a 3.25" hole. Problem is that my ram is
3.5". I would like to use my boring head
rather than a fly cutter. Does anybody make a
R8 male by R8 female extension? Around
5" would do it.

Think again.

And you will realize that a "collet" needs to be compressed which your
extension would not be.

Your best bet would be to get a shaft like 3/4", and bore a hole to
fit your cutter, and use a weld-on style setscrew to hold it. And mae
the cuts light.

i

Thanks,

Bill



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R8 extension? Do they exist?
 

On Jun 10, 9:21*pm, Ignoramus13673 ignoramus13...@NOSPAM.
13673.invalid wrote:

Think again.

And you will realize that a "collet" needs to be compressed which your
extension would not be.

Uh, wha? Boring heads are not typically held in collets. They have
their own arbors - the arbor threads into the boring head.

However, you're right in that R8 is not self locking. The extension
would have to have a small draw bolt to hold the boring arbor inside.


Your best bet would be to get a shaft like 3/4", and bore a hole to
fit your cutter, and use a weld-on style setscrew to hold it. And mae
the cuts light.

Or just get a long boring bar (roughly the same idea). However, this
is not ideal, and it sounds like Bill doesn't want to do this.

A spindle extension would likely have the most rigidity as it would be
larger in diameter than a boring bar extension. May have to lower the
knee to adjust the boring diameter, but sometimes life sucks.

An extension could be turned on a lathe. PITA though. In fact, I'd
probably just turn a male R8 taper on to one end (not trivial, but not
murder either), and the boring head thread in the other. Turning a
female R8 taper would be *way* more involved, and it likely wouldn't
be concentric enough to do perform useful work beyond holding a single-
point tool anyway. The boring head thread could be completed in 30min
or less.

Regards.

Robin

R8 extension? Do they exist?
 

wrote:
On Jun 10, 9:21 pm, Ignoramus13673 ignoramus13...@NOSPAM.
13673.invalid wrote:

Think again.

And you will realize that a "collet" needs to be compressed which
your extension would not be.

Uh, wha? Boring heads are not typically held in collets. They have
their own arbors - the arbor threads into the boring head.

However, you're right in that R8 is not self locking. The extension
would have to have a small draw bolt to hold the boring arbor inside.


Your best bet would be to get a shaft like 3/4", and bore a hole to
fit your cutter, and use a weld-on style setscrew to hold it. And mae
the cuts light.

Or just get a long boring bar (roughly the same idea). However, this
is not ideal, and it sounds like Bill doesn't want to do this.

A spindle extension would likely have the most rigidity as it would be
larger in diameter than a boring bar extension. May have to lower the
knee to adjust the boring diameter, but sometimes life sucks.

An extension could be turned on a lathe. PITA though. In fact, I'd
probably just turn a male R8 taper on to one end (not trivial, but not
murder either), and the boring head thread in the other. Turning a
female R8 taper would be *way* more involved, and it likely wouldn't
be concentric enough to do perform useful work beyond holding a
single- point tool anyway. The boring head thread could be completed
in 30min or less.

Feed the table/saddle up.
Sheesh, you youngsters G




--

John R. Carroll
www.machiningsolution.com

R8 extension? Do they exist?
 

I may have a long boring bar for sale

On 2008-06-11, John R. Carroll jcarroll@ubu wrote:
wrote:
On Jun 10, 9:21 pm, Ignoramus13673 ignoramus13...@NOSPAM.
13673.invalid wrote:

Think again.

And you will realize that a "collet" needs to be compressed which
your extension would not be.

Uh, wha? Boring heads are not typically held in collets. They have
their own arbors - the arbor threads into the boring head.

However, you're right in that R8 is not self locking. The extension
would have to have a small draw bolt to hold the boring arbor inside.


Your best bet would be to get a shaft like 3/4", and bore a hole to
fit your cutter, and use a weld-on style setscrew to hold it. And mae
the cuts light.

Or just get a long boring bar (roughly the same idea). However, this
is not ideal, and it sounds like Bill doesn't want to do this.

A spindle extension would likely have the most rigidity as it would be
larger in diameter than a boring bar extension. May have to lower the
knee to adjust the boring diameter, but sometimes life sucks.

An extension could be turned on a lathe. PITA though. In fact, I'd
probably just turn a male R8 taper on to one end (not trivial, but not
murder either), and the boring head thread in the other. Turning a
female R8 taper would be *way* more involved, and it likely wouldn't
be concentric enough to do perform useful work beyond holding a
single- point tool anyway. The boring head thread could be completed
in 30min or less.

Feed the table/saddle up.
Sheesh, you youngsters G





--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
more readers you will need to find a different means of
posting on Usenet.
http://improve-usenet.org/

R8 extension? Do they exist?
 

Ignoramus13673 wrote:
I may have a long boring bar for sale

Of course you do!
Who Else?
LOL

Feed the table/saddle up.
Sheesh, you youngsters G

--

John R. Carroll
www.machiningsolution.com

R8 extension? Do they exist?
 

On Jun 10, 9:56*pm, "John R. Carroll"
wrote:


Feed the table/saddle up.
Sheesh, you youngsters G

Bill's quill (I assume he means quill) is too big to fit through the
hole which leads to the hole he's trying to bore, so feeding the table/
saddle up will still cause a collision.

Sheesh indeed!

Regards,

Robin

R8 extension? Do they exist?
 

wrote:
On Jun 10, 9:56 pm, "John R. Carroll"
wrote:


Feed the table/saddle up.
Sheesh, you youngsters G

Bill's quill (I assume he means quill) is too big to fit through the
hole which leads to the hole he's trying to bore, so feeding the
table/ saddle up will still cause a collision.

Sheesh indeed!

LOL

Ronin,
You get the proper bar and feed down with the table and up with the quill.
That's why the make the feed thingy run in both directions.
Well, that and back gear.
Us old geezers know a thing or two you know sprout wink


Regards,

And to you as well.
Now.
Get a Molsen's in Ye' hoser!



--

John R. Carroll
www.machiningsolution.com

R8 extension? Do they exist?
 

wrote in message
...
On Jun 10, 9:56 pm, "John R. Carroll"
wrote:


Feed the table/saddle up.
Sheesh, you youngsters G

Bill's quill (I assume he means quill) is too
big to fit through the
hole which leads to the hole he's trying to
bore, so feeding the table/
saddle up will still cause a collision.

Jeez---yes I meant QUILL. Sometimes my
brain/fingers interface gets a little out of
whack.

I can do it with a 7" or so long bar. chunk of
1 1/4 CR, turn one end to 7/8" to fit my
largest R8, slot the other for a single point
tool. No biggy. What I would LIKE is to
have the ease of adjustment the boring head
provides. I may try turning a 1" dia. piece
of 4140 to 1/2" to fit the boring head, and
brazing a tip on the other end. Boring head
diameter is 2", cutter would be around 5" long.
Going to take a while either way---it's a
wallowed out
front pivot hole on a John Deere 4WD tractor
front axle mount.

The idea of turning a long male R8 by male
boring head thread adapter crossed my mind,
but I'm pretty sure the boring head thread is
metric. Possible, but kind of a pain in the
butt
on a 1948 South Bend lathe.

Bill

R8 extension? Do they exist?
 

On Jun 10, 11:45*pm, "BillM" wrote:
...
I can do it with a 7" or so long bar. *chunk of
1 1/4 CR, turn one end to 7/8" to fit my
largest R8, slot the other for a single point
tool. *No biggy. *What I would LIKE is to
have the ease of adjustment the boring head
provides. * ...
Bill

You could put a set screw behind the bit in the slot to adjust it
outward. Put some paper tape around the setscrew head and graduate at
least 1/6th of a circle with a protractor, using the Allen wrench
handle for a pointer. A 1/4-20 setscrew feeds 0.050 per turn. 5 degree
marks would indicate 0.0014" increase in diameter.

If the end of a 7" bar is hard to hold steady enough to slot, drill a
hole for the bit and use setscrews crosswise to guide it. Then you
wouldn't lose your lathe center hole if the taper needed adjustment.

R8 extension? Do they exist?
 

By the way, the OP could probably get by if he used a "toolholder" as
opposed to a collet, and a long end mill. That could give you extra 8"
or so, but will be expensive.

i

On 2008-06-11, Jim Wilkins wrote:
On Jun 10, 11:45•£Äpm, "BillM" wrote:
...
I can do it with a 7" or so long bar. •£Ächunk of
1 1/4 CR, turn one end to 7/8" to fit my
largest R8, slot the other for a single point
tool. •£ÄNo biggy. •£ÄWhat I would LIKE is to
have the ease of adjustment the boring head
provides. •£Ä ...
Bill

You could put a set screw behind the bit in the slot to adjust it
outward. Put some paper tape around the setscrew head and graduate at
least 1/6th of a circle with a protractor, using the Allen wrench
handle for a pointer. A 1/4-20 setscrew feeds 0.050 per turn. 5 degree
marks would indicate 0.0014" increase in diameter.

If the end of a 7" bar is hard to hold steady enough to slot, drill a
hole for the bit and use setscrews crosswise to guide it. Then you
wouldn't lose your lathe center hole if the taper needed adjustment.

--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
more readers you will need to find a different means of
posting on Usenet.
http://improve-usenet.org/

R8 extension? Do they exist?
 

On Tue, 10 Jun 2008 19:30:12 -0700, "John R. Carroll"
wrote:

Ignoramus13673 wrote:
I may have a long boring bar for sale

Of course you do!
Who Else?
LOL

Feed the table/saddle up.
Sheesh, you youngsters G


Well...Ive got a couple as well.....the 1.5" x 18" is on loan to one
of the local machine shops....hummm..its been a couple years....about
time he paid for it.....


Gunner