Screwhead chuck

**Christophe Mineau** · May 2, 2018, 01:27 AM

Hi,
I have always been attracted by the lantern chucks I have seen posted here at HMT, and have planned to make one, one day ...
But as I was recently shopping at the local hardware store, suddenly the light came. I saw a kind of big hose brass fitting like this one :

I thought that I could do something quick with that, just adding a brass cap nut and a core screw in order to hold any hex screw driver tip to lock the screw against the cap.

Here are the main parts :
- on the left, I machined and tapped a sleeve that will be "loctited" inside the brass.
- the M10 screw will have to get an hex female hole at the end to receive an hex bit like the one above on the picture.
- The brass body has its main part turned down to make the shaft
- The cap was surfaced true, on both sides, and a 8 mm hole is center drilled.

And here the collection of bushings in order to fit any screw diameter : 2, 2.5, 3, 3.5, 4, 4.5, 5, 6
they are lightly counter sunk in order to fit either flat or counter sunk headed screws
The screw head has been (badly) knurled and the hex tip has been made.
That's actually the most difficult part of the job. I drilled a hole smaller that the hex diagonal and then pressed an hex tip in it.
I removed it and tried to file the inside with small files and a dremel in order to get a slip fit.
I had to use a dye to readjust the somewhat expended threads as well.

And here is the assembly and mounted on the lathe.

**Paul Jones** · May 2, 2018, 11:32 AM

Christophe,

I like your adaptation of the hose brass fitting. Thank you for all the details for making the screw chuck.

Regards,
Paul

**Ralphxyz** · Sep 1, 2018, 02:25 PM

Nice, Thanks!!

Ralph

**mklotz** · Sep 1, 2018, 02:59 PM

Some other thoughts re the threaded rod with the hex hole...

Buy a cheap screwdriver already fitted with a hex socket and retaining magnet.

Cut off the end and thread and attach knurled thumb knob.

or

Turn down rod and loctite into a hole drilled into an appropriate sized bolt

**Christophe Mineau** · Sep 2, 2018, 01:45 AM

Thanks Ralph and Marv, good point, if I had to redo, I would try that.

**desbromilow** · Sep 28, 2020, 03:06 AM

Originally Posted by mklotz

Some other thoughts re the threaded rod with the hex hole...

Buy a cheap screwdriver already fitted with a hex socket and retaining magnet.

Cut off the end and thread and attach knurled thumb knob.

or

Turn down rod and loctite into a hole drilled into an appropriate sized bolt

or use a 5/16" SHCS since the socket on that is 1/4" hex - that's what I did with my lantern chuck.

**WmRMeyers** · Sep 2, 2023, 09:42 AM

Originally Posted by desbromilow

or use a 5/16" SHCS since the socket on that is 1/4" hex - that's what I did with my lantern chuck.

That is a GREAT stealable idea! Consider it stolen! With thanks!

Bill

**Shelly142** · Sep 12, 2018, 12:02 AM

Christophe,
Nicely done. I especially like the utilization of as many off the shelf items as possible.
Like you said there are many different approaches to lantern chucks and this one can
be added to the mix. Thanks for sharing.

**rayh__** · Sep 24, 2020, 07:33 PM

I very much enjoy it when things are repurposed to ones special needs.
You did a good job.
Thanks for posting.

**uv8452** · Sep 2, 2023, 01:43 AM

Christophe,
the hex screwdriver tip within the chuck is a valuable feature. That's better than friction. I will make a new chuck.
I bought 10 1/4" caps.
Then reduced the (future) mandrel to a ø of 12.5 mm
Then cut the 1/4" thread not to the theoretical depth but to a 'playless' fit with the caps (luckily all were of the same size)
I assume (against an engineering law) that the playless fit will center the caps to the mandrel.
The outer face of the caps were true to the mandrel, so I just drilled the necessary diameters: 1.4, 1.6, 2.0, 2.5