I picked up a few IHMSA rear sights for the T/C Contender. The stock
elevator stem has a crude black finish that is not hard. Its already
wearing away in the dovetail.

I did some Super High Intensity Tinkering, and found out that you can
open the base dovetail and the elevator stem of a Williams FoolProof
fits right in.... However, there is a problem, as the IHMSA sight
(possibly T/C made investment casting) uses a 6-40 thread, and the
Williams FP uses a 6-48 thread. Result- the elevator screw makes about
three turns, then everything stacks up.

I picked up some stainless steel hypodermic tubing, .148 OD and .110 ID
to thread internally. Drill out the existing thread, then press in the
threaded tubing. Waa-laa, correct thread.

Sight base is steel (suprise!)
Web thickness around existing internal thread is @.200"

The tubing comes out as .1475 OD on my Starret. The load will be light,
just the elevator stem. What should I drill the existing thread out with
(diameter) and follow up with a reamer (diameter)?

I dimly remember a drill should be about .005" under the diameter of the
reamer.

What should the final diameter be for a press fit?

On 07/14/2011 12:19 PM, Louis Ohland wrote:
I picked up a few IHMSA rear sights for the T/C Contender. The stock
elevator stem has a crude black finish that is not hard. Its already
wearing away in the dovetail.

I did some Super High Intensity Tinkering, and found out that you can
open the base dovetail and the elevator stem of a Williams FoolProof
fits right in.... However, there is a problem, as the IHMSA sight
(possibly T/C made investment casting) uses a 6-40 thread, and the
Williams FP uses a 6-48 thread. Result- the elevator screw makes about
three turns, then everything stacks up.

I picked up some stainless steel hypodermic tubing, .148 OD and .110 ID
to thread internally. Drill out the existing thread, then press in the
threaded tubing. Waa-laa, correct thread.

Sight base is steel (suprise!)
Web thickness around existing internal thread is @.200"

The tubing comes out as .1475 OD on my Starret. The load will be light,
just the elevator stem. What should I drill the existing thread out with
(diameter) and follow up with a reamer (diameter)?

I dimly remember a drill should be about .005" under the diameter of the
reamer.

What should the final diameter be for a press fit?

Grain-o-salt: I ain't no professional machinist.

I don't think you should go too far undersized, if at all, and I think
you should use adhesive to hold things together.

Why? Because if you make things undersized enough to really hold that
tubing in there, it's thin wall enough to squeeze the ID, and jam things up.

Without adhesives you'd be wanting to thread the outside, and do a
helicoil kind of thing, or use a good thick wall so you don't squeeze
the tube. But if you're really intending this to be a light torque
application, then why not just glue?

I'd go with Loctite, unless you're concerned about temperature in which
case I'd go with Epoxy (something sophisticated, like JB-weld).

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

"Tim Wescott" wrote in message
...
On 07/14/2011 12:19 PM, Louis Ohland wrote:
I picked up a few IHMSA rear sights for the T/C Contender. The stock
elevator stem has a crude black finish that is not hard. Its already
wearing away in the dovetail.

I did some Super High Intensity Tinkering, and found out that you can
open the base dovetail and the elevator stem of a Williams FoolProof
fits right in.... However, there is a problem, as the IHMSA sight
(possibly T/C made investment casting) uses a 6-40 thread, and the
Williams FP uses a 6-48 thread. Result- the elevator screw makes about
three turns, then everything stacks up.

I picked up some stainless steel hypodermic tubing, .148 OD and .110 ID
to thread internally. Drill out the existing thread, then press in the
threaded tubing. Waa-laa, correct thread.

Sight base is steel (suprise!)
Web thickness around existing internal thread is @.200"

The tubing comes out as .1475 OD on my Starret. The load will be light,
just the elevator stem. What should I drill the existing thread out with
(diameter) and follow up with a reamer (diameter)?

I dimly remember a drill should be about .005" under the diameter of the
reamer.

What should the final diameter be for a press fit?

Grain-o-salt: I ain't no professional machinist.

I don't think you should go too far undersized, if at all, and I think you
should use adhesive to hold things together.

Drill undersized. Ream to size. Sounds like what the OP said he was going
to do.

the tube. But if you're really intending this to be a light torque
application, then why not just glue?

Loctite sleeve and bushing locker is perfect although it might be too strong
for this application. I know it works on press in sleeves on engine coolant
systems just fine. That used to be Loctite Green.


I'd go with Loctite,

Me too.

unless you're concerned about temperature in

Loctite sleeve and bushing works upto 200 degrees on coolant systems on
engines. I tend to prefer to drill and pipe tap, but that's just me.

which case I'd go with Epoxy (something sophisticated, like JB-weld).

J-B weld is some awesome stuff. I've used it to hold hydraulics together
with some mechanical assistance. Most of your clear epoxies and especially
your 1-5 minute varieties will soften up at higher temps too. However for
this application a needle tip dab of 5 minute epoxy might be good too.


JMNSHO

How much relief for Loctite? Depending on how much space that Loctite
can fill, I might be able to drill the elevator threads out and slip in
the liner without reaming.

The best is the enemy of the good. Use a 6-48 tap in a collet chuck to
align the sight, change out to a drill, clean up the threaded hole,
change back to the 6-48 tap, thread the liner onto the tap, goop up the
liner, then lower the liner on the tap into the hole. Unchuck the tap
and let it sit in the liner until the Loctite firms up. After the
Loctite sets, simply unscrew the tap.

I think I can use an end mill and plunge cut for the gib lock bushing,
that should tighten up the dovetail, just like on the Williams FoolProof.

On 7/14/2011 15:39, Bob La Londe wrote:
"Tim Wescott" wrote in message
...
On 07/14/2011 12:19 PM, Louis Ohland wrote:
I picked up a few IHMSA rear sights for the T/C Contender. The stock
elevator stem has a crude black finish that is not hard. Its already
wearing away in the dovetail.

I did some Super High Intensity Tinkering, and found out that you can
open the base dovetail and the elevator stem of a Williams FoolProof
fits right in.... However, there is a problem, as the IHMSA sight
(possibly T/C made investment casting) uses a 6-40 thread, and the
Williams FP uses a 6-48 thread. Result- the elevator screw makes about
three turns, then everything stacks up.

I picked up some stainless steel hypodermic tubing, .148 OD and .110 ID
to thread internally. Drill out the existing thread, then press in the
threaded tubing. Waa-laa, correct thread.

Sight base is steel (suprise!)
Web thickness around existing internal thread is @.200"

The tubing comes out as .1475 OD on my Starret. The load will be light,
just the elevator stem. What should I drill the existing thread out with
(diameter) and follow up with a reamer (diameter)?

I dimly remember a drill should be about .005" under the diameter of the
reamer.

What should the final diameter be for a press fit?

Grain-o-salt: I ain't no professional machinist.

I don't think you should go too far undersized, if at all, and I think
you should use adhesive to hold things together.

Drill undersized. Ream to size. Sounds like what the OP said he was
going to do.

the tube. But if you're really intending this to be a light torque
application, then why not just glue?

Loctite sleeve and bushing locker is perfect although it might be too
strong for this application. I know it works on press in sleeves on
engine coolant systems just fine. That used to be Loctite Green.


I'd go with Loctite,

Me too.

unless you're concerned about temperature in

Loctite sleeve and bushing works upto 200 degrees on coolant systems on
engines. I tend to prefer to drill and pipe tap, but that's just me.

which case I'd go with Epoxy (something sophisticated, like JB-weld).

J-B weld is some awesome stuff. I've used it to hold hydraulics together
with some mechanical assistance. Most of your clear epoxies and
especially your 1-5 minute varieties will soften up at higher temps too.
However for this application a needle tip dab of 5 minute epoxy might be
good too.


JMNSHO

On Thu, 14 Jul 2011 12:29:36 -0700, Tim Wescott
wrote:

On 07/14/2011 12:19 PM, Louis Ohland wrote:
I picked up a few IHMSA rear sights for the T/C Contender. The stock
elevator stem has a crude black finish that is not hard. Its already
wearing away in the dovetail.

I did some Super High Intensity Tinkering, and found out that you can
open the base dovetail and the elevator stem of a Williams FoolProof
fits right in.... However, there is a problem, as the IHMSA sight
(possibly T/C made investment casting) uses a 6-40 thread, and the
Williams FP uses a 6-48 thread. Result- the elevator screw makes about
three turns, then everything stacks up.

I picked up some stainless steel hypodermic tubing, .148 OD and .110 ID
to thread internally. Drill out the existing thread, then press in the
threaded tubing. Waa-laa, correct thread.

Sight base is steel (suprise!)
Web thickness around existing internal thread is @.200"

The tubing comes out as .1475 OD on my Starret. The load will be light,
just the elevator stem. What should I drill the existing thread out with
(diameter) and follow up with a reamer (diameter)?

I dimly remember a drill should be about .005" under the diameter of the
reamer.

What should the final diameter be for a press fit?

Grain-o-salt: I ain't no professional machinist.

I don't think you should go too far undersized, if at all, and I think
you should use adhesive to hold things together.

Why? Because if you make things undersized enough to really hold that
tubing in there, it's thin wall enough to squeeze the ID, and jam things up.

Without adhesives you'd be wanting to thread the outside, and do a
helicoil kind of thing, or use a good thick wall so you don't squeeze
the tube. But if you're really intending this to be a light torque
application, then why not just glue?

I'd go with Loctite, unless you're concerned about temperature in which
case I'd go with Epoxy (something sophisticated, like JB-weld).

I use JB Weld on my Super 14 Contenders.
Holds up well enough for holding in dovetail sights

Gunner

Whenever a Liberal utters the term "Common Sense approach"....grab your
wallet, your ass, and your guns because the sombitch is about to do
something damned nasty to all three of them.