Looking For A Special Tap


wlw19958
 

Hi There, 

I am looking to have a special tap made.  In particular,
I want a more-or-less standard plug type tap, 60°
3/8" - 10 Left-Hand. 

Does anyone have a source they would like to share?

Thanks for your time!
-Blue Chips-
Webb


Andrei
 

Making a tap is well within the reach of a home machinist, and I needed a very unusual tap to try and repair my G Boley watchmakers lathe. After watching a f...
www.youtube.com



From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of wlw19958 <wlw-19958@...>
Sent: Thursday, February 25, 2021 2:41 PM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: [SouthBendLathe] Looking For A Special Tap
 
Hi There, 

I am looking to have a special tap made.  In particular,
I want a more-or-less standard plug type tap, 60°
3/8" - 10 Left-Hand. 

Does anyone have a source they would like to share?

Thanks for your time!
-Blue Chips-
Webb


Steve Wells
 

What class of fit are you looking Webb?

 

Steve

 

 

From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> On Behalf Of wlw19958
Sent: Thursday, February 25, 2021 2:42 PM
To: SouthBendLathe@groups.io
Subject: [SouthBendLathe] Looking For A Special Tap

 

Hi There, 

I am looking to have a special tap made.  In particular,
I want a more-or-less standard plug type tap, 60°
3/8" - 10 Left-Hand. 

Does anyone have a source they would like to share?

Thanks for your time!
-Blue Chips-
Webb


wlw19958
 

Hi There,

Steve, I'm not that versed in thread sizing and classes. 
I would say that the fit of the old parts are in the H1 to H3
class.  I really don't have any way of measuring the internal
threads of the old parts to find this out exactly. 

Perhaps mentioning what parts I am trying to make will help
I have several telescoping steadies and one follower that
have been denuded of their parts.  I recently purchased a
steady that had its parts (or more correctly, most of them)
and this has given me examples of the parts I need to make
for the other ones (and to replace the worn and missing parts
on the steady I just got). 

The only part that will be trouble for me to make will be the
brass fingers.  These have a 3/8" - 10 LH internal thread. 
This is too small for me to try internal threading with a single
point tool.  Hence, I need a tap to make these.

I know there is a guy on eBay the sells them but at $70 a set,
I think I will be better off buying a tap plus I might make some
extras to sell.  Also, these brass fingers wear quickly so being
able to produce replacements when I need them would be good. 

Good Luck!
-Blue Chips-
Webb


Andrei
 

Webb, 

from your description it does not sound like your brass fingers MUST be a specific thread with a left twist. you can probably substitute more standard size threads and live happily ever after. 

Just because the originals were LH thead it does not mean you can't convert them to something that is more common. 

Find the path of least resistance, unless you are trying to do museum restauration, in which case, original specs would trump your convenience. 


From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of wlw19958 <wlw-19958@...>
Sent: Thursday, February 25, 2021 6:14 PM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: Re: [SouthBendLathe] Looking For A Special Tap
 
Hi There,

Steve, I'm not that versed in thread sizing and classes. 
I would say that the fit of the old parts are in the H1 to H3
class.  I really don't have any way of measuring the internal
threads of the old parts to find this out exactly. 

Perhaps mentioning what parts I am trying to make will help
I have several telescoping steadies and one follower that
have been denuded of their parts.  I recently purchased a
steady that had its parts (or more correctly, most of them)
and this has given me examples of the parts I need to make
for the other ones (and to replace the worn and missing parts
on the steady I just got). 

The only part that will be trouble for me to make will be the
brass fingers.  These have a 3/8" - 10 LH internal thread. 
This is too small for me to try internal threading with a single
point tool.  Hence, I need a tap to make these.

I know there is a guy on eBay the sells them but at $70 a set,
I think I will be better off buying a tap plus I might make some
extras to sell.  Also, these brass fingers wear quickly so being
able to produce replacements when I need them would be good. 

Good Luck!
-Blue Chips-
Webb


Jim_B
 

I just noticed you were open to having a custom tap made. 
You can try Victor tools in NYC. 



OTOH, you MAY be able to single point the thread. 

 10 TPI thread has a double depth of .128” 
0.375 - 0.128= 0.247”

So you need a threading tool that will fit into a (approximate) 0.247 (0.250 Hole)

TWO OPTIONS. 

The tool on the bottom is from McMaster Carr. I used it to make 1/4-26 (BSF) threads. I also broke it so the tip of the point is missing. 
I measures 0.200 and should just fit into your starting hole. Its solid carbide and very expensive at $30 and fragile. But it fits the best. 

The second is fro Little Machine Shop .  Its width is 0.252 and would need some substantial grinding on the backside to clear the hole. 

Here is more data on the MCMasters tool. 


 

Myself, I would give it a try wit the McMasters tool. 

On Feb 25, 2021, at 4:13 PM, Steve Wells <wswells@...> wrote:

What class of fit are you looking Webb?
 
Steve
 
 
From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> On Behalf Of wlw19958
Sent: Thursday, February 25, 2021 2:42 PM
To: SouthBendLathe@groups.io
Subject: [SouthBendLathe] Looking For A Special Tap
 
Hi There,  

I am looking to have a special tap made.  In particular, 
I want a more-or-less standard plug type tap, 60° 
3/8" - 10 Left-Hand.  

Does anyone have a source they would like to share? 

Thanks for your time!
-Blue Chips-
Webb 


Jim B.





--
Jim B


fred eisner
 

andrei - i agree with you in most cases but not this one - in order for the telescoping fingers to work properly they must be left-handed - just my 2cents worth - fred


From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of Andrei <calciu1@...>
Sent: Thursday, February 25, 2021 6:21 PM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: Re: [SouthBendLathe] Looking For A Special Tap
 
Webb, 

from your description it does not sound like your brass fingers MUST be a specific thread with a left twist. you can probably substitute more standard size threads and live happily ever after. 

Just because the originals were LH thead it does not mean you can't convert them to something that is more common. 

Find the path of least resistance, unless you are trying to do museum restauration, in which case, original specs would trump your convenience. 

From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of wlw19958 <wlw-19958@...>
Sent: Thursday, February 25, 2021 6:14 PM
To: SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: Re: [SouthBendLathe] Looking For A Special Tap
 
Hi There,

Steve, I'm not that versed in thread sizing and classes. 
I would say that the fit of the old parts are in the H1 to H3
class.  I really don't have any way of measuring the internal
threads of the old parts to find this out exactly. 

Perhaps mentioning what parts I am trying to make will help
I have several telescoping steadies and one follower that
have been denuded of their parts.  I recently purchased a
steady that had its parts (or more correctly, most of them)
and this has given me examples of the parts I need to make
for the other ones (and to replace the worn and missing parts
on the steady I just got). 

The only part that will be trouble for me to make will be the
brass fingers.  These have a 3/8" - 10 LH internal thread. 
This is too small for me to try internal threading with a single
point tool.  Hence, I need a tap to make these.

I know there is a guy on eBay the sells them but at $70 a set,
I think I will be better off buying a tap plus I might make some
extras to sell.  Also, these brass fingers wear quickly so being
able to produce replacements when I need them would be good. 

Good Luck!
-Blue Chips-
Webb


Jim_B
 

OOPS. I said 1/4-26 it was 5/16-22




Jim B,

On Feb 25, 2021, at 7:17 PM, Jim_B <jim@...> wrote:

I just noticed you were open to having a custom tap made. 
You can try Victor tools in NYC. 



OTOH, you MAY be able to single point the thread. 

 10 TPI thread has a double depth of .128” 
0.375 - 0.128= 0.247”

So you need a threading tool that will fit into a (approximate) 0.247 (0.250 Hole)

TWO OPTIONS. 
<0A6C9311-212F-420D-B426-5885FB4E96CD_1_105_c.jpeg>

The tool on the bottom is from McMaster Carr. I used it to make 1/4-26 (BSF) threads. I also broke it so the tip of the point is missing. 
I measures 0.200 and should just fit into your starting hole. Its solid carbide and very expensive at $30 and fragile. But it fits the best. 

The second is fro Little Machine Shop .  Its width is 0.252 and would need some substantial grinding on the backside to clear the hole. 

Here is more data on the MCMasters tool. 


 
<Screen Shot 2021-02-25 at 7.16.04 PM.jpeg>

Myself, I would give it a try wit the McMasters tool. 

On Feb 25, 2021, at 4:13 PM, Steve Wells <wswells@...> wrote:

What class of fit are you looking Webb?
 
Steve
 
 
From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> On Behalf Of wlw19958
Sent: Thursday, February 25, 2021 2:42 PM
To: SouthBendLathe@groups.io
Subject: [SouthBendLathe] Looking For A Special Tap
 
Hi There,  

I am looking to have a special tap made.  In particular, 
I want a more-or-less standard plug type tap, 60° 
3/8" - 10 Left-Hand.  

Does anyone have a source they would like to share? 

Thanks for your time!
-Blue Chips-
Webb 


Jim B.





--
Jim B

--
Jim B


Shadetree
 

Hey Blue Chips,
You might try using a 3/4-10 LH tap and modifying it to your needs if you don't have a lot of parts to make. I saw a episode of "This Old Tony" during my lunch break that showed him using one to make a non standard thread similar to what you are looking for. MSC and others stock LH taps and it is likely cheaper than a special. Unless you have lots of 3/8-10 tapping to do. Just a thought. :)

Shadetree


Rick
 

On Thu, Feb 25, 2021 at 06:14 PM, wlw19958 wrote:
I know there is a guy on eBay the sells them but at $70 a set,
I think I will be better off buying a tap plus I might make some
extras to sell.  Also, these brass fingers wear quickly so being
able to produce replacements when I need them would be good.
Buy or make ones that use roller bearings instead of the brass ones.  They will not wear out.


Steve Wells
 

Webb,

Victor Machine Supply used to stock that tap, but as of late, it’s probably

special order with the COVID effects.

I think they still have the RH in stock.

But they will arrange do a one-off for you.

Give them a call or email them.

They would probably be the most cost-effective also.

The number you would need is TALF-3/8-10

 

VICTOR MACHINERY EXCHANGE

12155 STEPHENS ROAD

WARREN, MI 48089-3962

(800) 723-5359

sales@....

 

Steve

 

From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> On Behalf Of wlw19958
Sent: Thursday, February 25, 2021 6:15 PM
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] Looking For A Special Tap

 

Hi There,

Steve, I'm not that versed in thread sizing and classes. 
I would say that the fit of the old parts are in the H1 to H3
class.  I really don't have any way of measuring the internal
threads of the old parts to find this out exactly. 

Perhaps mentioning what parts I am trying to make will help
I have several telescoping steadies and one follower that
have been denuded of their parts.  I recently purchased a
steady that had its parts (or more correctly, most of them)
and this has given me examples of the parts I need to make
for the other ones (and to replace the worn and missing parts
on the steady I just got). 

The only part that will be trouble for me to make will be the
brass fingers.  These have a 3/8" - 10 LH internal thread. 
This is too small for me to try internal threading with a single
point tool.  Hence, I need a tap to make these.

I know there is a guy on eBay the sells them but at $70 a set,
I think I will be better off buying a tap plus I might make some
extras to sell.  Also, these brass fingers wear quickly so being
able to produce replacements when I need them would be good. 

Good Luck!
-Blue Chips-
Webb


Steve Wells
 

Let me know if you can’t fine one, and I’ll look through my stock.

 

Steve

 

From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> On Behalf Of Steve Wells
Sent: Thursday, February 25, 2021 8:36 PM
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] Looking For A Special Tap

 

Webb,

Victor Machine Supply used to stock that tap, but as of late, it’s probably

special order with the COVID effects.

I think they still have the RH in stock.

But they will arrange do a one-off for you.

Give them a call or email them.

They would probably be the most cost-effective also.

The number you would need is TALF-3/8-10

 

VICTOR MACHINERY EXCHANGE

12155 STEPHENS ROAD

WARREN, MI 48089-3962

(800) 723-5359

sales@....

 

Steve

 

From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> On Behalf Of wlw19958
Sent: Thursday, February 25, 2021 6:15 PM
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] Looking For A Special Tap

 

Hi There,

Steve, I'm not that versed in thread sizing and classes. 
I would say that the fit of the old parts are in the H1 to H3
class.  I really don't have any way of measuring the internal
threads of the old parts to find this out exactly. 

Perhaps mentioning what parts I am trying to make will help
I have several telescoping steadies and one follower that
have been denuded of their parts.  I recently purchased a
steady that had its parts (or more correctly, most of them)
and this has given me examples of the parts I need to make
for the other ones (and to replace the worn and missing parts
on the steady I just got). 

The only part that will be trouble for me to make will be the
brass fingers.  These have a 3/8" - 10 LH internal thread. 
This is too small for me to try internal threading with a single
point tool.  Hence, I need a tap to make these.

I know there is a guy on eBay the sells them but at $70 a set,
I think I will be better off buying a tap plus I might make some
extras to sell.  Also, these brass fingers wear quickly so being
able to produce replacements when I need them would be good. 

Good Luck!
-Blue Chips-
Webb


Colin Fera
 

5/16-22 is British standard fine Thread. 
From UK Working on an old rifle?
Looks like you can get one for about $16 plush shipping:

On Feb 25, 2021, at 16:39, Jim_B <jim@...> wrote:

OOPS. I said 1/4-26 it was 5/16-22




Jim B,

On Feb 25, 2021, at 7:17 PM, Jim_B <jim@...> wrote:

I just noticed you were open to having a custom tap made. 
You can try Victor tools in NYC. 



OTOH, you MAY be able to single point the thread. 

 10 TPI thread has a double depth of .128” 
0.375 - 0.128= 0.247”

So you need a threading tool that will fit into a (approximate) 0.247 (0.250 Hole)

TWO OPTIONS. 
<0A6C9311-212F-420D-B426-5885FB4E96CD_1_105_c.jpeg>

The tool on the bottom is from McMaster Carr. I used it to make 1/4-26 (BSF) threads. I also broke it so the tip of the point is missing. 
I measures 0.200 and should just fit into your starting hole. Its solid carbide and very expensive at $30 and fragile. But it fits the best. 

The second is fro Little Machine Shop .  Its width is 0.252 and would need some substantial grinding on the backside to clear the hole. 

Here is more data on the MCMasters tool. 


 
<Screen Shot 2021-02-25 at 7.16.04 PM.jpeg>

Myself, I would give it a try wit the McMasters tool. 

On Feb 25, 2021, at 4:13 PM, Steve Wells <wswells@...> wrote:

What class of fit are you looking Webb?
 
Steve
 
 
From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> On Behalf Of wlw19958
Sent: Thursday, February 25, 2021 2:42 PM
To: SouthBendLathe@groups.io
Subject: [SouthBendLathe] Looking For A Special Tap
 
Hi There,  

I am looking to have a special tap made.  In particular, 
I want a more-or-less standard plug type tap, 60° 
3/8" - 10 Left-Hand.  

Does anyone have a source they would like to share? 

Thanks for your time!
-Blue Chips-
Webb 


Jim B.





--
Jim B

--
Jim B


jgrounds
 



You can try Victor tools in NYC. 



OTOH, you MAY be able to single point the thread. 
They are now in Warren, Michigan.  You may get what you order. I ordered some drill bits online from them and did not receive the items described or pictured. I had ordered the same items several times while they were in NYC with no problems at all.


wlw19958
 

Hi There,

Thanks for all the suggestions.  As pointed out by others,
the fingers must be left-hand thread or it won't work.

I don't think single point threading is an option for me at least. 
The length of the thread in the hole is about 2 inches and it is
a blind hole.  I know I cannot due that type of deep small hole
single point threading without developing an ulcer.  And I have
to make over 10 of these.

The idea of modifying a 3/4 - 10 tap is interesting but I still see
a problem with chip clearance but I will keep that idea on the
back burner. 

Making a tap is one of my goals but it is the provision for clearance
of the cutting edges that present the biggest problem.  I have plans
for making a relieving fixture for a lathe but it will take a lot of effort
and the materials would cost more than a custom made tap. 

I will contact Victor about a special made tap and see what they
charge for the service.

Thanks Again for all the help
-Blue Chips-
Webb


KA9EGW
 

3/8-16 LH? Victor machinery and mcmaster among many others list them


ww_big_al
 

Don’t know  where you live but Newman Tools say they make custom taps.

https://www.newmantools.com/taps/tapsinch.htm

I have never used their service.

Al

 

From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> On Behalf Of KA9EGW
Sent: Friday, February 26, 2021 7:31 AM
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] Looking For A Special Tap

 

3/8-16 LH? Victor machinery and mcmaster among many others list them


Rangelov
 

Hi,

Are you sure that it isn't an Acme thread?  3/8 x 10 is a standard (ish) Acme screw size.

You could go with a standard thread pitch.  It will make a finer adjustment.  That might make it easier to dial in.

The down side is you could put more force into the part due to greater mechanical advantage.

I will check my follow and steady rests. The follow rest has the adjuster bolt. The steady has the micrometer adjustment.

Dimitar


Jim_B
 

Taps will not normally thread to a depth of 2”. You will need an extended length tap. More $$ 
OTOH you most likely don’t need 2” depth for strength. You do for adjustment range. 
You might consider using a small boring bar to open up the 0.250 root bore to 0.375 after about 3/4”. 
I have modified an OTS bar to do just that.  I turned down the 1/4 section to 3/16 and let the tool extend 1/16”. 
I only needed to bore an inch. You would need to turn it a bit longer. 




Jim B,

On Feb 26, 2021, at 12:52 AM, wlw19958 <wlw-19958@...> wrote:

Hi There,

Thanks for all the suggestions.  As pointed out by others,
the fingers must be left-hand thread or it won't work.

I don't think single point threading is an option for me at least. 
The length of the thread in the hole is about 2 inches and it is
a blind hole.  I know I cannot due that type of deep small hole
single point threading without developing an ulcer.  And I have
to make over 10 of these.

The idea of modifying a 3/4 - 10 tap is interesting but I still see
a problem with chip clearance but I will keep that idea on the
back burner. 

Making a tap is one of my goals but it is the provision for clearance
of the cutting edges that present the biggest problem.  I have plans
for making a relieving fixture for a lathe but it will take a lot of effort
and the materials would cost more than a custom made tap. 

I will contact Victor about a special made tap and see what they
charge for the service.

Thanks Again for all the help
-Blue Chips-
Webb

--
Jim B


wlw19958
 

Hi There, 

There is no question that the screw used to extend the finger
is not an ACME thread.  It isn't a worn ACME either.



When this part is threaded into the finger, there isn't any play (if it were a worn
ACME, there would be lots of play).  Here is a close-up.



What I see is, this thread form is a 60° but has a shallower depth.  I haven't measured
the depth yet.  From the formula in the HTRAL handbook, full depth 10 pitch thread
should be .064952" or .065" (rounding to the nearest thousandth).  This would give
a minor diameter of .245".

The pilot hole in the finger is about 19/64".  This is .297" (rounded).  This means the
tap doesn't have to be made to full thread depth and that should make it stronger.

Some have suggested substituting a 3/8-16 LH tap.  Some have done this when
fabricating parts for these telescoping steadies but if one uses a finer pitch, one
does not get the full range of finger movement and loose some capacity (either
loosing the ability to come all the way to center or not able to open all the way to
maximum for large diameter parts). 

The depth of the thread isn't completely known at this time.  The fingers were modified
to accept a replaceable tip and they were drilled all the way into the bottom of
the 3/8-10 LH threads.  Even though this has happened, I can estimate the original
depth to be about 1-7/8" to 2".  I have purchased some worn fingers that haven't
had any mods so I will be able to get a more accurate measurement once they have
arrived.   Once I know the correct depth, I can pass that on to the makers of the tap
so it can be made accordingly.

Anyway, I do appreciate the suggestions and help I've received so far.

Good Luck!
-Blue Chips-
Webb