T-handle tap wrench for M1.2 taps?

[Maletrain]

So as not to hijack the treads that TurboWhiz and GaryHinshaw are producing for the Npossible couplers, I am starting this thread to ask about tap wrenches to hold the M1.2 screws that will be needed for some of the metal underbodies.

The small (M1.0 to M1.6) taps that I own have approximately 1/16" 0.63mm square shanks, and some are loose in the smallest T-handle tap wrench that I own.   Most of the tap handles that I have really do not grip the smallest tap shanks, even though some say they go down to "1/16" or 1.5mm" - because they really don't.

What I would really like to find is a T-handle wrench that is sure to grip such small shanks and also has a controlled runout feature for guiding it in a drill press or mill.  Something like this, but smaller:  https://www.amazon.com/AD-INTERNATIONAL-Precision-Spinnable-Accurate/dp/B0CJTZ5P6Z/ref=sr_1_1_sspa .  Even a simple concentric hole in the top of the handle would do for runout control - but ratchet handles can't be controlled that way (and that is all that I have the fits most of these tiny taps).

I know there are some superb mini machinists on TRW, so it seems like the place to ask.

[Scottl]

I put my tap in my pin vice.

[Chris333]

I also put all small taps in a pin vice. I have 1.4mm and 00-90 both permanently in their own pin vices.

[Maletrain]

I could use a pin vice, but for metal, I prefer the T-handle. 

In metals, I usually go a small fraction of a turn, then back it up a bit to clear chips, then another small fraction of a turn, all the while keeping it wet with "Tap Magic" fluid.  Using a pin vice, I tend to lose track of the "straight-in" orientation.  Keeping the tap from wallowing out the entrance hole is easiest if the top of the tap holder is itself held in position by something rigid such as a sliding holder in a drill press chuck.  It works even better if I can drill the pilot hole and then tap it without moving the piece, so that everything remains lined-up perfectly.

Perfection is probably not needed for threading the mounting holes for Npossible couplers, but I also sometimes need to tap for tiny screws in things like locos.

[bbussey]

Amazon should have them, as a number of their China-based suppliers make them.

[Maletrain]

Amazon says they have them, but Amazon has not turned out to be a credible source of product info.  Some of what they sell did not turn out to be able to grab a 1/16" square shank.  More credible places I usually frequent, like McMaster-Carr, do not list them for tap square dimensions below 0.11", and I need something a bit less than 0.062" to grab a few of my smallest taps, which seem to be on the small side of their tolerance band for their square shanks.

I am hoping that somebody here actually has a model that they know works and can give me a link or at least a reference.

[nscaler711]

Yeah well I put my taps in my Dremel at 20k rpm!!


I definitely use a pin vise, I haven't seen a T handle small enough to handle the taps we would use in this hobby, granted I am not a fan of T handles in the regular taps either... I have been known to use a ratchet and a modified socket... I also have used a dremel... but at much lower speeds and softer materials like Aluminum and brass. Granted, I use a dremel incorrectly by applying pressure to the shaft to slow it down, above its stall speed and a lower torque. somehow it is still alive, even after 20 years... the 18650s are definitely on their way out...

When tapping definitely use some form of lubricant, specialty or otherwise, breaking a tap off in metal especially as small as our taps can get is almost impossible to recover.
I have yet to find drill bits that small that will chew out a broken tap. I have also yet to find a tool small enough to back out a tap either.

[Chris333]

We use cordless drills all day long to drill and tap into steel. But only down to 6-32 nothing smaller than that.

I'd guess most model railroad frame metal would be kind of softish.

[Chris333]

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No idea if these will work for you, but I subscribe to this channel and this is a new video.

[Maletrain]

The tap handles in the video look to still be sized for square tap shanks larger than those on M1.2 taps.

I am going to disagree with the guy in the video about his ratcheting tap handle being too large for small taps.  I just used one almost exactly like that one because it was the only one I had that would hold my M1.6 tap.  I had no trouble "feeling" the amount of chip binding while using it to tap a hole through a 1/8" think angle iron last Tuesday.  And, I was not even using a guide, but I was tapping in the vertical direction.  With a guide for the upper end of the handle in a press of some sort, the weight of the tap handle is not really relevant.

So, my issue is only finding a T-handle that has a small enough jaw to hold the smallest of my taps.

[Chris333]

It looks like most micro tap wrenches are home made:

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[Maletrain]

If you watch those videos, all they are really doing is drilling a hole the size of the tap shaft and then using a set screw to hold it from turning in that hole.  No square hole to drive the tap by its square shank.  Might as well use a pin vice. For taps of this size, torque is not the issue, the issue is feel, and control of the tap orientation to the hole being tapped, as with a guide of some sort.  The problem with guides that sit on the surface of the object being tapped is that some of our models do not have flat surfaces to support that type of guide in a stable orientation.

So, I am still hoping to find one similar to the link I first provided, but with a small enough square driving gripper.

[Chris333]

I wasn't saying you need to build anything that was shown. Just that your best bet might be to build whatever you want.

Like maybe take a pin vice that holds your tap well and add a T handle to it?

This is small, but maybe no small enough.
https://littlemachineshop.com/products/product_view.php?ProductID=2852&category=-561984047

There are small gear pullers that hold a tiny die with a set screw. They might hold a tap. And they have a T handle.
https://www.horizonhobby.com/product/gear-puller-1mm-5mm-shaft/EFLA212.html
you can find them cheaper on ebay.
https://www.ebay.com/itm/313937736638

[Maletrain]

The gear pullers don't apply rotational torque to the pins, so not useful as tap holders.

The tap handle in the first link says "1/16" for the smallest square shank it can hold, and that number is close to what I need.  But, already having some handles that say the same thing but are actually too loose at that size, I am hoping for somebody to tell me that they have one that does work, so I can buy one that won't disappoint me like the others already have.

I might try to modify a small 4-jaw one that I already have, but would prefer the 2-jaw type.

[thomasjmdavis]

Like several folks above, I use my trusty Starrett pin vise.  In any case, my two 00-90 taps are from MTL sets, and have round shafts, so a T handle wouldn't be much use. Back in the day when I did a small amount of tap and die work, for small taps, I had a Starrett 174 T-handle.  At the time, I was tapping things larger than 00-90, but it would hold taps and even drill bits down to tiny sizes.  They list it as 0 to 1/4 inch.  I cannot vouch that it actually goes to zero, but you could contact them and ask about whether it will grab a 00-90 and turn it.  You can see one here:
https://www.starrett.com/details?cat-no=174


Nevermind.... I found another listing with clearer photos and a better description, the 174 only goes down to 0 gauge, not zero inches, making it still too big for your 00 application.  Old memory.  Still, I wish I still had it.