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3326 Chuck, Set Screw Swap ?
Posted: Tue Jun 26, 2018 2:35 pm
by nuhobby
Hi,
I have stumbled onto a very nice old Jacobs 3326 drill chuck. Only slight irritation is that the set-screw takes a 3/16 hex-tool rather than the 'universal' 5/32 hex-tool. Has anyone ever found a set-screw to put a 5/32 tool hex screw in the 3326 chuck?
Thanks,
Chris
Re: 3326 Chuck, Set Screw Swap ?
Posted: Tue Jun 26, 2018 2:49 pm
by JPG
Not since they became standardized. They at one time existed.
Re: 3326 Chuck, Set Screw Swap ?
Posted: Wed Jun 27, 2018 1:46 am
by rpd
nuhobby wrote:Hi,
I have stumbled onto a very nice old Jacobs 3326 drill chuck. Only slight irritation is that the set-screw takes a 3/16 hex-tool rather than the 'universal' 5/32 hex-tool. Has anyone ever found a set-screw to put a 5/32 tool hex screw in the 3326 chuck?
Thanks,
Chris
That chuck shipped with a 10ER.
10ER's use a total of four different hex key sizes.
These are the four chucks I own.

- drill chucks.jpg (319.94 KiB) Viewed 5268 times
from the left
1 & 2 - came with 10ER's - marked Jacobs 3326 - 3/16 hex key - K32 chuck key
3 - came with Mark 5 (greenie) - marked Jacobs Multi-Craft MC-3326 - 5/32 hex key - K32 chuck key
4 - purchased on EBay - marked Jacobs Multi-Craft MC8K26 - 5/32 hex key - KK chuck key
Re: 3326 Chuck, Set Screw Swap ?
Posted: Wed Jun 27, 2018 9:02 pm
by cham-ed
The 3326 should be the best of the bunch at least originally. It is the top of the line. The later ones were more of looser design.
Re: 3326 Chuck, Set Screw Swap ?
Posted: Fri Jun 29, 2018 4:15 pm
by chapmanruss
Ron's picture above shows two of the Jacobs 3326 Chuck which started out as a chuck for the Model 10E & 10ER and replaced the Jacobs 33B Chuck on an adapter. When the Mark 5 was being introduced the plan was for all possible set screws be changed to the 5/32" Allen Wrench size. The first Jacobs 3326 Chucks sent out with the Mark 5 still had the 3/8" threaded hole the same as ones for the Model 10's using a 3/16" Allen Wrench but they used a special size 3/8" set screw that uses a 5/32" Allen Wrench. Eventually the hole was drilled & tapped at 5/16" to take a standard 5/32" Allen Wrench size set screw. So to answer your question Chris, yes the was a 3/8" set screw that used a 5/32" Allen Wrench.
Below is the three Jacobs 3326 Chucks used for the Shopsmiths.

- 3326 Chucks.jpg (355.12 KiB) Viewed 5161 times
Note the differences in the set screws.
The other two chucks in Ron's picture are the Jacobs Multi-Craft Chucks supplied by Shopsmith Inc. with the Mark V's for a time.
Re: 3326 Chuck, Set Screw Swap ?
Posted: Fri Jun 29, 2018 9:27 pm
by nuhobby
Thanks all for the info!
Standardization of fasteners and threads is interesting... I like to tell my brothers how the Stanley-plane thread sizes pre-date the SAE standards.
Chris