MIMF

Where can I find a screw type endpin jack in gold for an Eastman 905 archtop guitar?

The short answer is probably "China".
You could contact Eastman in California at (909) 868-1633 and ask.
You could try this one from Stewmac: http://www.stewmac.com/Pickups_and_Elec ... _Jack.html
or this one from eBay: http://www.ebay.com/itm/Switchcraft-Mon ... 1290735690
I think the very best endpin jacks (in terms of reliability) come with EMG but I don't know how to get them short of ordering an acoustic pickup.

I just took a look at that model guitar. Does it have a cello type hanger for the tailpiece? So you'll need something you can tighten from the outside (which is probably what you asked for). There's this: http://www.stewmac.com/Pickups_and_Elec ... _Jack.html and there are other sources for similar parts.

I think this guitar has hidden controls so you'll attach a length of shielded cable to the screw in jack, install the jack and fish the cable out the treble F hole and make your connections.

Unless I misunderstand.

And I'm back.

If this guitar has the cello type hanger and you want to use the endpin jack as a strap button, you'll need to leave a bit of the threaded portion out. This is where the hanger goes. Then the end can be used as a strap button. I've seen the other kind of end pin jack with two grooves, but not on the screw in type.

Once again, I'm assuming the cello type hanger.

One more time. I was thinking that because the guitar is an archtop, you needed the screw in endpin. Not so. You can install it and tighten from the outside, just like the part says. You'll still need that two groove nut cover.

...assuming the cello type hanger.

And you thought you were done with me...

A little searching found a shot of an Eastman arch top showing the hanger. It is metal with a large hole where the jack and/or strap button would go. It looks like it will fit over the end pin jack that David showed. If this is the same hanger that is on your guitar, you're in good shape. Install the jack, slip the tailpiece over it and you're in business. If the strap button (that covers the locking nut) is too big, you might be able to put it on after installing the tailpiece.

Of course, all you asked is where to get one, not how to install it.

Why not search some on Amazon. Hope you can easily find one with desired requirement at Amazon or eBay.