doublegunshop.com - home
Posted By: Travis S Ithaca Flues refurb? - 11/23/21 02:23 PM
I have refurbished a 16ga elector field grade flues and replacing the stock was part of the project.

I have the gun fully assembled with all but one of the screws in. Currently the stock is tight in all the places that need be but the last screw hole I need to drill and screw to be placed is the main top strap screw.

My concern is that if I do this wrong it may pull the frame away from the wood inletting versus pulling it into the wood inletting.

Am I over thinking this or are there things I need to consider?

This is the last step to finishing this project.

Many thanks and a happy Thanksgiving to all.
Posted By: SKB Re: Ithaca Flues refurb? - 11/23/21 02:32 PM
No, you are not over thinking things at all. You need to get that screw in the proper location. In my mind, the top tang screw being a wood screw on the Flues is a design flaw.

To locate it properly, turn a bushing on the lathe that barely fits the hole on the tang on the OD and drill the ID to the minor diameter on your screw. By doing this in one setup on the lathe you will maintain concentricity. Make the bushing at least 2" long or so in order to have something to hold on to when drilling.

Best of luck,
Steve
Posted By: Kutter Re: Ithaca Flues refurb? - 11/23/21 09:17 PM
I like to place the screw just off center towards the back edge of the hole in the top strap.
That way the screw pulls the frame back into the wood when tightened.

It doesn't take much for what you want to accomplish and still have the screw look right when seated.
You only need to move the center of the pilot hole .010" to accomplish this.

I usually set the stock with frame attached in the mill vise. A drill press & vise can also be used.
I use a long adj clamp to pull the action into the wood for this final fit while I'm doing this top tang screw operation.
That makes sure the frame is set into the wood as deeply and firmly as it can be before I place the additional draw (however slight) of the top tang screw into the mix.

Level the action/stock assembly in the vise.
I use a drill bit of whatever size that just fits the screw hole in the tang to line up the assembly with the chuck.
Place the drill bit upside down in the drill chuck so the solid end is hanging out.

Move the stock/frame assembly around till the end of the bit will easily drop into the tang hole.
Recheck from side and back for square.

Move assembly the required amt ( .010") so the bit will drill the pilot hole closer to the rear of the screw hole in the tang.

Replace that upside-down centering drill bit wih the required size pilotdrill bit for the screw you are using and drill the pilot hole.

The Flues set up is not very good. There's nothing in the stock inletting and triggerplate relationship that pulls the pieces together as there is in so many others.
Flues often have their top stock 'fingers' cracked, or broken and repaired from the stock loosening and the frame rotating up and back pushing those fragile pieces off.

Many times you find that top tang wood screw replaced with a repair done with a machine screw that threads into a steel nut imbedded in epoxy just underneath the tang.
Holds a lot better than the wood screw if done right and the wood isn't all oil soaked when the repair is done.
Looks good too.
Posted By: Hammergun Re: Ithaca Flues refurb? - 11/24/21 01:19 PM
I've converted both my Flues to the machine screw set up described by Kutter. That simple mod really helps keep things tight. Been good for about 25 years.

The original wood screw set up is a design flaw as SKB stated. No way that it can hold up to repeated use.
Posted By: Travis S Re: Ithaca Flues refurb? - 11/25/21 10:39 AM
Thanks for the replies with great Info.

On the embedded nut mod... is this just a nut imbedded and epoxied just at the surface the stock inletting while being tight against the underside of the top strap? How about a bushing say .5" long with some grooves cut around the outer diameter so the epoxy will have a better holding surface?
Posted By: Hammergun Re: Ithaca Flues refurb? - 11/25/21 12:49 PM
I inletted the nut on the underside of the the wood. I wouldn't trust a nut held only by epoxy. A bushing would be even better.
Posted By: Kutter Re: Ithaca Flues refurb? - 11/25/21 04:43 PM
I've seen it done several ways. The quickest is to just use a common machine screw 'nut' and they are often inletted into the wood just under the top tang and epoxy glued in place.
You could reverse taper the flats of the nut slightly so the glue imbeds the nut more securely. It's still just the epoxy and it's secure grip on the surrounding wood that holds it in place.

Placing it on the underside gives it a lot better strength. It doesn't even really need to be 'glued into place if the nut fits it's inlet tight enough not to drop out while assembling, but it makes life simpler.

A bushing will get you the max amt of thread engagement betw the two fasteners. But the bushing's grip on the stock is still dependent on the wood being oil free for the epoxy.
In this case the new stock elliminates that issue.

A thin walled internally threaded bushing with a flange on the bottom to pull on the wood as the screw is tightened might be best. Maybe overkill but as long as you are making a bushing it's not hard to add that feature.

Lots of ways to handle the Flues top tang screw problem.
Posted By: Travis S Re: Ithaca Flues refurb? - 11/25/21 04:48 PM
This is a gun I plan on keeping and shooting so I am going with the bushing on the bottom of the wood plan. Thanks again for all the input. You guys are the best.

Happy thanksgiving.
© The DoubleGun BBS @ doublegunshop.com