I've got a Unisaw that I want to attach an extension table to the rear of.
There's two holes (approx 3/8" diameter) already drilled in the rear flange
of the cast iron top (it came from the factory that way), but they're not
tapped; just through-drilled. They're a little too small for clearance of
a 3/8" bolt; it would be nice if they were whatever the tap drill diameter
for a 3/8 UNC is supposed to be, but I haven't measured them exactly, so
I'm not sure.

I suspect the easiest way to attach something would be to tap those two
holes and bolt on a piece aluminum angle, to which my plywood table would
get attached. How difficult will it be to tap these holes? I've tapped
holes before, but never in cast iron. Does it go easy? Is there any risk
that I'll damage the top? What if I end up having to drill some additional
holes in the flange?

"Roy Smith" wrote in message
...
I've got a Unisaw that I want to attach an extension table to the rear of.
There's two holes (approx 3/8" diameter) already drilled in the rear
flange
of the cast iron top (it came from the factory that way), but they're not
tapped; just through-drilled. They're a little too small for clearance of
a 3/8" bolt; it would be nice if they were whatever the tap drill diameter
for a 3/8 UNC is supposed to be, but I haven't measured them exactly, so
I'm not sure.

My guess you have the required tap. 3/8-16 tap drill is 5/16. If not, why
not use a bolt & nut that will pass? May need to go metric for a better fit

I suspect the easiest way to attach something would be to tap those two
holes and bolt on a piece aluminum angle, to which my plywood table would
get attached. How difficult will it be to tap these holes? I've tapped
holes before, but never in cast iron. Does it go easy? Is there any risk
that I'll damage the top? What if I end up having to drill some
additional
holes in the flange?

In article ,
"Rick S. Carusi" wrote:

My guess you have the required tap. 3/8-16 tap drill is 5/16. If not, why
not use a bolt & nut that will pass?

Because it's danged near impossible to get to the back side of the flange
to hold a nut in place. The sheet metal cabinet is in the way. I tried
reaching in from the throat opening, but I'm not enough of a contortionist
to get my arm where it needs to go.

On Sun, 23 Apr 2006 17:24:21 -0400, Roy Smith wrote:

I've got a Unisaw that I want to attach an extension table to the rear of.
There's two holes (approx 3/8" diameter) already drilled in the rear flange
of the cast iron top (it came from the factory that way), but they're not
tapped; just through-drilled. They're a little too small for clearance of
a 3/8" bolt; it would be nice if they were whatever the tap drill diameter
for a 3/8 UNC is supposed to be, but I haven't measured them exactly, so
I'm not sure.


Mine (a 1987 model) is tapped to accept an M10-1.0 bolt, which is what
was used to attach a Jet-Lock fence rail.


--
Chuck Taylor
http://home.hiwaay.net/~taylorc/contact/

in order:
5/16-18 NC is F (.2570"/6.528mm)
8-1.25mm is H (.2660/6.756mm)
5/16-24 NF is I (.2720"/6.909mm)
8-1.00mm is J (.2770"/7.036mm)
5/16-32 NEF is 9/32" drill hole size
9-1.25mm is 5/16"
3/8-16 NC is 5/16"
9-1.00mm is O (.3160"/8.026mm)
9-0.75mm is 21/64"
3/8-24 NF is Q (.3320"/8.433mm)
10-1.50mm is R (.3390"/8.611mm)
10-1.25mm is S (.3480"/8.839mm)
10-1.00mm is 23/64"

from kbctools.com catalogue, not double checked/verified. Letter equiv's
from Machinery's Handbook. If you want to know if, consult it. If you need
to know how to make the tool to make the tool, consult it.

If you screw up you can use a heli-coil, etc.



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Cast iron drills, taps and machines great. When tapping, back out often. It
does tend to clog.

"Roy Smith" wrote in message
...
I've got a Unisaw that I want to attach an extension table to the rear of.
There's two holes (approx 3/8" diameter) already drilled in the rear
flange
of the cast iron top (it came from the factory that way), but they're not
tapped; just through-drilled. They're a little too small for clearance of
a 3/8" bolt; it would be nice if they were whatever the tap drill diameter
for a 3/8 UNC is supposed to be, but I haven't measured them exactly, so
I'm not sure.

I suspect the easiest way to attach something would be to tap those two
holes and bolt on a piece aluminum angle, to which my plywood table would
get attached. How difficult will it be to tap these holes? I've tapped
holes before, but never in cast iron. Does it go easy? Is there any risk
that I'll damage the top? What if I end up having to drill some
additional
holes in the flange?

I suspect the easiest way to attach something would be to tap those two
holes and bolt on a piece aluminum angle, to which my plywood table would
get attached. How difficult will it be to tap these holes? I've tapped
holes before, but never in cast iron. Does it go easy? Is there any risk
that I'll damage the top? What if I end up having to drill some additional
holes in the flange?


Cast iron is one of the easier metals to both drill and tap.

In article , wrote:

I suspect the easiest way to attach something would be to tap those two
holes and bolt on a piece aluminum angle, to which my plywood table would
get attached. How difficult will it be to tap these holes? I've tapped
holes before, but never in cast iron. Does it go easy? Is there any risk
that I'll damage the top? What if I end up having to drill some additional
holes in the flange?


Cast iron is one of the easier metals to both drill and tap.

Thanks, that's what I was hoping to hear.

On Sun, 23 Apr 2006 15:24:21 -0600, Roy Smith wrote:

I've got a Unisaw that I want to attach an extension table to the rear
of.
There's two holes (approx 3/8" diameter) already drilled in the rear
flange
of the cast iron top (it came from the factory that way), but they're not
tapped; just through-drilled. They're a little too small for clearance
of
a 3/8" bolt; it would be nice if they were whatever the tap drill
diameter
for a 3/8 UNC is supposed to be, but I haven't measured them exactly, so
I'm not sure.

I suspect the easiest way to attach something would be to tap those two
holes and bolt on a piece aluminum angle, to which my plywood table would
get attached. How difficult will it be to tap these holes? I've tapped
holes before, but never in cast iron. Does it go easy? Is there any
risk
that I'll damage the top? What if I end up having to drill some
additional
holes in the flange?

Cast iron taps fairly easy, but it clogs the tap, so back it out to clear
the chips, then tap anouther 1/4 - 1/2 turn or so.
DAGS comes up with this site for drill sizes:
http://www.newmantools.com/tapdrill.htm





--
Using Opera's revolutionary e-mail client: http://www.opera.com/mail/

Those are designed "exactly" for that purpose. Those holes
match the Biesemeyer back rail, which an outfeed table can
be attached.

The Biesmeyer rail is attached with thru bolts and nuts.

Go here for detailed instructions on how to build the
outfeed and bolt sizes....

http://www.biesemeyer.com/print/comm...e%20Manual.pdf

No drilling required......


Roy Smith wrote:

I've got a Unisaw that I want to attach an extension table to the rear of.
There's two holes (approx 3/8" diameter) already drilled in the rear flange
of the cast iron top (it came from the factory that way), but they're not
tapped; just through-drilled. They're a little too small for clearance of
a 3/8" bolt; it would be nice if they were whatever the tap drill diameter
for a 3/8 UNC is supposed to be, but I haven't measured them exactly, so
I'm not sure.

On Sun, 23 Apr 2006 17:24:21 -0400, Roy Smith wrote:

I've got a Unisaw that I want to attach an extension table to the rear of.
There's two holes (approx 3/8" diameter) already drilled in the rear flange
of the cast iron top (it came from the factory that way), but they're not
tapped; just through-drilled. They're a little too small for clearance of
a 3/8" bolt; it would be nice if they were whatever the tap drill diameter
for a 3/8 UNC is supposed to be, but I haven't measured them exactly, so
I'm not sure.

I suspect the easiest way to attach something would be to tap those two
holes and bolt on a piece aluminum angle, to which my plywood table would
get attached. How difficult will it be to tap these holes? I've tapped
holes before, but never in cast iron. Does it go easy? Is there any risk
that I'll damage the top? What if I end up having to drill some additional
holes in the flange?


I don't know where you get your Unisaws, but where I get mine those
holes are tapped.

Frank

Roy Smith wrote:
I've got a Unisaw that I want to attach an extension table to the rear of.
There's two holes (approx 3/8" diameter) already drilled in the rear flange
of the cast iron top (it came from the factory that way), but they're not
tapped; just through-drilled. They're a little too small for clearance of
a 3/8" bolt;

Why not just use a 1/4" or 5/16" bolt with a nut on the back side?

Chris

"Roy Smith" wrote in message
...
I've got a Unisaw that I want to attach an extension table to the rear of.
There's two holes (approx 3/8" diameter) already drilled in the rear
flange
of the cast iron top (it came from the factory that way), but they're not
tapped; just through-drilled. They're a little too small for clearance of
a 3/8" bolt; it would be nice if they were whatever the tap drill diameter
for a 3/8 UNC is supposed to be, but I haven't measured them exactly, so
I'm not sure.

I suspect the easiest way to attach something would be to tap those two
holes and bolt on a piece aluminum angle, to which my plywood table would
get attached. How difficult will it be to tap these holes? I've tapped
holes before, but never in cast iron. Does it go easy? Is there any risk
that I'll damage the top? What if I end up having to drill some
additional
holes in the flange?

Maybe I'm not understanding this question very well. You want to attach an
extension to the BACK of your Unisaw? For use as an outfeed? If you do,
the miter slots will be useless, unless you have a way to cut them through.
Either way, drilling and tapping holes in cast iron is easy and explained in
other replies.

Dave

On Mon, 24 Apr 2006 08:46:38 -0400, Roy Smith wrote:

In article , wrote:

I suspect the easiest way to attach something would be to tap those two
holes and bolt on a piece aluminum angle, to which my plywood table would
get attached. How difficult will it be to tap these holes? I've tapped
holes before, but never in cast iron. Does it go easy? Is there any risk
that I'll damage the top? What if I end up having to drill some additional
holes in the flange?


Cast iron is one of the easier metals to both drill and tap.

Thanks, that's what I was hoping to hear.


Check them again!! there tapped. 3/8" - 24. If they are not tapped
and you have a recent Unisaw, call your dealer and make him replace
the table.

Frank

"Teamcasa" wrote:
Maybe I'm not understanding this question very well. You want to attach an
extension to the BACK of your Unisaw? For use as an outfeed?

Yes, exactly.

If you do,
the miter slots will be useless, unless you have a way to cut them through.

I figure I'd just cut two dados in the top to line up with the slots.

"Roy Smith" wrote in message
...
"Teamcasa" wrote:
Maybe I'm not understanding this question very well. You want to attach
an
extension to the BACK of your Unisaw? For use as an outfeed?

Yes, exactly.

If you do,
the miter slots will be useless, unless you have a way to cut them
through.

I figure I'd just cut two dados in the top to line up with the slots.

I'm sorry! I pictured you asking about adding a cast iron extension to the
back of your saw! I re-read the original post again and realized you did
not say what I thought it did.

Dave



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