Allen wrench size?

[Dave H (MI)]

I am repairing a Senco framing nailer. I have a cap screw that I need to remove but in all the allen wrenches I have around here none of them fit. The parts list says it is a Screw Shc Slc 8-32 X 1/2. 1/8 is too big and 3/32 is too small for the screw head. Anyone know?

 

[Dieseltech]

Maybe Metric?

 

[J Hamilton]

Probably a metric size

 

[TimV]

Would seem odd--though hardly unprecedented--to have a metric head on a SAE fastener. Do you have a 7/64? Plenty around--any hardware store should have one.
7/64 hex wrench

 

[Hemmjo]

It is not metric if is a 8-32. You can find a metric wrench to fit, but that is just because there is overlap between M and SAE sizes.

From data at The Bolt Depot, I would expect and 8-32 socket head cap screw head to be 9/64 wrench size, but if 1/8 is too big and 3/32 is too small, then as mentioned 7/64 is your best bet.

If you have a metric set 5.5mm should fit.
Bolt Depot 8 32 socket head cap screw

 

[timcasbolt]

(quoted from post at 06:25:13 11/29/23) It is not metric if is a 8-32. You can find a metric wrench to fit, but that is just because there is overlap between M and SAE sizes.

From data at The Bolt Depot, I would expect and 8-32 socket head cap screw head to be 9/64 wrench size, but if 1/8 is too big and 3/32 is too small, then as mentioned 7/64 is your best bet.

If you have a metric set [b:6736d73a33]5.5mm [/b:6736d73a33]should fit.
Bolt Depot 8 32 socket head cap screw

retty sure you meant 2.5mm.

 

[Jim.ME]

From several sources:
9/64'' is the standard size wrench for a #8 socket head screw.
7/64'' is the standard size wrench for a #6 socket head screw.

If 1/8'' (= 8/64'') is too big and 3/32'' (= 6/32'') is too small, it sounds like either it is a #8 with a nonstandard head or it is actually a #6 screw.

Either way 7/64'' falls between 1/8'' and 3/32'' and is found in most hex key wrench sets.

#6-32 sockethead screw

 

[Dave H (MI)]

I should probably mention that I have a near hoarder level collection of tools. Included in the allen wrenches are a very new Craftsman set and a fairly new Cobalt set (Lowes). The 1/8 wrenches in these sets are not the same size with Cobalt on the mic being correct and Craftsman is not...probably just put away wrong at some point. Neither set has the 9/64 wrench but I found an old set of Companion 9KE which did and it turned the screw out for me. Really appreciate the help! Interesting was that the Companion has a stock number of 9-46281. This looks like a Sears stock number to me as their tools were largely in division 9. I rang up a lot of tools on the registers in the couple years I worked there.

 

[TimV]

Glad you got it out, Dave! Not nitpicking, just for my information, did you mean you got it out with the 7/64 I'd mentioned or the 9/64 that Jim.ME said would have been correct? Only asking as it would be even odder than your original problem of a 1/8 being too large if a 9/64 (which is larger yet) did indeed fit. I also have a bunch of hex keys (boxes full!) of unknown provenance as I find it hard to pass up 'dollar boxes' or similar sources of varied tools at garage sales and similar venues, and that will, over a few decades, build up quite a collection--if you can dignify it with that term!-of 'spare' hex wrenches, not to mention drill bits, wrenches, sockets, and other things! Will have to check my old Craftsman set--a Christmas present from my grandparents circa 1978--and see if it has a 7/64. Most of these do have the size stamped into the wrench itself, though it's mighty small on ones of that size--might want to see if yours does to ensure exactly what it's supposed to be.

 

[Jim.ME]

(quoted from post at 11:11:34 11/29/23) I should probably mention that I have a near hoarder level collection of tools. Included in the allen wrenches are a very new Craftsman set and a fairly new Cobalt set (Lowes). The 1/8 wrenches in these sets are not the same size with Cobalt on the mic being correct and Craftsman is not...probably just put away wrong at some point. Neither set has the 9/64 wrench but I found an old set of Companion 9KE which did and it turned the screw out for me. Really appreciate the help! Interesting was that the Companion has a stock number of 9-46281. This looks like a Sears stock number to me as their tools were largely in division 9. I rang up a lot of tools on the registers in the couple years I worked there.

Companion was the early brand name for tools sold at Sears and Roebuck stores. They were a lower priced alternative to the Craftsman tools. I have a few I got at a Sears store, so it is not surprising the tool numbers align.

My guess is your hex keys (Allen is a brand name--lol) are mixed up in their holders, as 9/64 is not smaller than 1/8'', which you posted was too big in your original post. If in doubt of the size, a caliper or a mic is your friend if you can't read a size stamped on the hex key.

 

[Hemmjo]

Oops 7/64 is close to 3.5 mm. Sorry about that

 

[Jim.ME]

(quoted from post at 13:00:15 11/29/23) Oops 7/64 is close to 3.5 mm. Sorry about that

7/64'' = 2.778 mm

 

[Hemmjo]

Yes you are correct. I should not try to respond with this little phone
screen.

 

[TimV]

Braved the cold and snow (only a few inches yet here in northern NY--the worst of the recent storms went south of us) to walk out to the garage, and found that my old Craftsman set (9 46683) does indeed have not one but two versions of both 7/64 and 9/64--long and short armed ones. Link below is an ebay listing of the same basic thing--nothing to do with me, just something I found for those curious.
9 46683 Craftsman hex key set

 

[Stephen Newell]

It's not enough they have to drive you nuts with metric bolts, they have metric Allen wrenches too.

 

[DoubleO7]

(quoted from post at 21:27:26 11/29/23) It's not enough they have to drive you nuts with metric bolts, they have metric Allen wrenches too.

Would you really expect a metric socket head bolt to have anything other than a metric hole??

 

[Check Break]

(quoted from post at 12:31:16 11/29/23) Braved the cold and snow (only a few inches yet here in northern NY--the worst of the recent storms went south of us) to walk out to the garage, and found that my old Craftsman set (9 46683) does indeed have not one but two versions of both 7/64 and 9/64--long and short armed ones. Link below is an ebay listing of the same basic thing--nothing to do with me, just something I found for those curious.
9 46683 Craftsman hex key set

I have one just like that purchased in 78 or 79. Still gets used once in a while.