Trouble trying to tap a small hole...6/32 size

savagesword

savagesword

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Aug 30, 2012
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Hi, I wanted to attach some pommels to the tang by drilling a hole in the bottom of the pommel and screwing it into the end of the tang. The thickness of the tang is .25" and I thought I could use a 6 /32 screw (counter sunk) + epoxy to hold it nicely. I got the hole drilled fine....but I keep breaking the tap as I try to use the hand tap tool to cut the threads. I'm using cutting oil and I've tapped many holes using a 1/4" tap and 3/8" tap... so I'm pretty good at it. But no matter how gentle I am...I keep breaking the damn tap in the hole at about 3/8" depth. I broke the Irwin set from Home Depot...then i ordered more expensive ones from ENCO...and broke those too. I've given up for now.

Any advice when trying to tap a hole this small? I'm using a #36 drill bit (that came with the tap set).

Thanks all!

Here's my tap and drill set I'm using....

632tap.jpg
 
Do you have a drill press? You can clamp your knife down and hand tap by turning the spindle. Make sure it is lined up dead straight first.

Moly-D is great tapping fluid by the way.

I'm not too experienced with tapping but so far have had good luck with the clamp, drill, hand twist the spindle method.

Use a taper tap also, they cut gradually and are better for starting a hole especially in tough to drill materials.
 
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Drill larger, use better taps, use forming taps, change tap size.

There are something about 6-32's that like to break.
It a rather large tap, in my world, but still a flimsy one.
I'd rather tap #2 than #6, go figure!

I tapped over 100 1-72 holes in Titanium this week, and expect I'll keep using that tap for the next several hundred holes!
 
Given the depth of the hole relative to its diameter, try a 7/32" or #33 drill.
 
The 2 best suggestions I can offer is buy good quality, American made taps, and do at least a rough sub-critical anneal on the end of the tang.
I found a huge difference in tap quality when I got some from a machine tool store, I'll never buy an Erwin tap again if I can find a better one availible.
For the anneal, I pre-heat the last 1-1/2" of tang to blue, then heat the very end to dull red, try to maintain that heat for a minute or 2, then air cool and repeat a couple more times.
On another note, 6/32 is pretty small for securing a sword pommel IMO. With a 1/4" thick tang you should be able to use at least 8/32, if you can drill with good precision then you can probably get away with 10/32. Personally I would use a 1/4-28 male thread on the tang and make a nut to secure the pommel, then get creative to make the nut aesthetically appropriate. A lot of swords have peen blocks which offers an option in this regard, counter sinking it into the pommel is also an option if you can figure out how to tighten it by cutting a slot into it or something. If it is a pemanent assembly you can leave the top of the nut standing out, cut a screwdriver slot into it with a hacksaw, then grind it flush after the final assembly is complete.
 
I'm with Justin.

Why are you tapping the tang for a screw....thread it for a nut at 1/4-28. Either thread the pommel and screw it on, then trim it to fit, or make a nice pommel nut. You can even make a recessed pommel nut that will be ground flush after final assembly ( or left slotted for a takedown).
 
Very good input Justin and Stacy! I was kinda fixed on using an allen-head screw.. ... but I can do much better with using a nut. Great advice and what a great deal of info I learned!! Thanks again
 
Another point, If you were to impact the pommel on the side, even with the epoxy, it will shear that 6/32 screw and pop that pommel right off (ask me how I know). 6/32 is not large enough to use as a primary fastener like that. The 1/4-20 is much more appropriate.
 
Use spiral point gun taps which you can get from Enco. Once you have broken a tap in a hole there may be bits of tap left in it which will break subsequent taps. Weld a threaded rod onto your tang and if you really want an Allen screw anneal then centerdrill and tap an Allen screw and use it as a nut. That is what I do

-Page
 
Another option if you are wanting the hex to show is a cylinder nut or an allen nut. They are threaded like a nut but round on the outside and use an allen wrench to tighten down. They are used in mainly air cylinder manufacture.
http://www.mcmaster.com/#allen-nuts/=maf1n5
 
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