Panda bolt stop screw woes

[AlNyhus]

Got a Panda here with a bolt stop screw issue. I'm pleading the 5th on this one as it came to me this way.

The hex recess is completely gone. It's hard to see in the pics but there's just a thin shell of the outer head section remaining. I've tried the simple stuff...a metric hex wrench, tapping a Torx bit into it, epoxying a Hex bit into the recess, and a couple of modified easy outs. Screw threads in the receiver were soaked in Kroil prior to trying anything.

Any thunks before I have to get jiggy with this thing on the mill? And if so, just drill the screw out and repair the receiver threads as needed? Small end mill?

I could probably just leave it alone but it's a TG style ejector with the pin for the ejector on the bolt release. I'd hate to have something happen at a tournament because you'd be "....screwed, blued and tattooed" as my Dad would say.

Thanks in advance! -Al

 

[LVLAaron]

Left hand drill bit?

 

[AlNyhus]

Left hand drill bit?

I've thought of that and have some.

 

[Jerry Wick]

Al, I think I would just leave it be. There's not much reason to remove the bolt release and the spring will likely never fail. So...good enough.

The upside is you'll never have to worry about it unscrewing and falling out. I had it happen...once. Now I know better.

 

[Fast14riot]

Got a soldering iron you can fit down in there?

 

[ricco1949]

As I see it you have two options, (1) leave well enough alone or (2) go at it with a carbide end mill and pick out the remaining springy thingy.

If no 2 fails then shoulda done no 1......

Actually if #2 fails then you could drill and ream remaining threads for appropriate size dowel pin. Probably need a through hole then to avoid same scenario....easy to tap out if needed.

 

[jackieschmidt]

It probably came loose on the previous owner and he loctited it in.

Did you try heating the aluminum around it with a soldering iron.

That being said. I kinda go along with @Jerry Wick. At the very least yo don’t have to worry about it falling out.

 

[1shot]

Orrr, there is one other option that hasn't been mentioned. All of the posters are far smarter at machining than I am. So, with that being said, you could always send it to Kelblys.

 

[AlNyhus]

It probably came loose on the previous owner and he loctited it in.

Did you try heating the aluminum around it with a soldering iron.

That being said. I kinda go along with @Jerry Wick. At the very least yo don’t have to worry about it falling out.

Tried heating it a couple ways...a pencil tip soldering iron on the screw and a heat gun on the area. I should probably leave it alone but that goes against my nature.

 

[liljoe]

I would be nibbling away at it with a ball end mill.
Joe

 

[Walt Krafft]

The Panda would be easy to square up in the mill. Nice hole to center off of. That hole will probably give you a good idea of the thread size, probably 8-36 or so. Call and find out. Drill it out and retap to clean the threads. When you call, order a couple of the screws. Easy peasy.

 

[Bob3700]

Al, figure out what thread dia n pitch. In the mill, start small with the drill n work up to the minor diameter. U may find the screw will collapse once drilled n the heat generated will also help loosen the screw.

 

[AlNyhus]

The thread is 5-40. Some Pandas have a hex head bolt and some just have a 5-40 set screw. The extra bolt stops I have are all .095 hole diameter for the screw. With the hex head bolt, the threaded portion was tuned down where it passes through the bolt stop.

I think I'll enlarge the hole to the point where it just clears the upper part of the bolt stop, get the bolt stop out and go from there. With the bolt stop out, all things are (should be???) possible.

 

[ricco1949]

Al,
The turned down section adds a new dimension to the dilemma.

If the turned down section passes entirely through the bolt stop and catches hole in the other side of slot how you gonna get it out? Seems it will just spin under the end mill once you've cut through the threaded part?

 

[AlNyhus]

I ended up using a 5/64" carbide ball end mill and made a centered up 'seat' in the bottom of the hex recess of the screw that was in there. Changed out for a 5/64" carbide flat end mill and went on in until it was j-u-s-t above the top edge of the bolt stop. Finding when to stop when it just cleared the top of the bolt stop took a bit of dirt clod 'cipherin' but it worked well. It passed cleanly through the .095 hole in the bolt stop. From there, it was a succession of number drill bits...one number at a time. At #42, (.093) I could feel a little shimmy in the bolt stop and was able to push the bolt stop out of the recess with a brass punch. Then a #38 (.101), dipped a decent 5-40 tap in some home brewed moly mixture and carefully ran the tap in, backing it up every half turn.

I really thought I'd end up having to go a 6-32 to clean things up but it turned out pretty well. The standard bolt stop screw threads nicely into the threads and with a bit of anti seize on the threads, it should be good for another 50,000 miles or 5 years...whichever comes first.

Thanks for the thoughts and suggestions. -Al

 

[ricco1949]

Nicely snuck up on...

I've chosen to use a through hole dowel pin when installing an aftermarket bolt release on 700's since you just tap out the remainder if it shears.

I considered a set screw however I was concerned with potentially breaking the tiny tap when threading or shearing the set screw in bolt operation and all those ramifications. I never even considered stripping the socket head as another potential failure.

After your ordeal I'll continue using dowel pins...less for Murphy to work on.

 

[AlNyhus]

Honestly, of all the Pandas and Kodiaks I've had and worked with, this is the only time I've ever seen this issue. It likely started when someone used a poor fitting 1/16" hex wrench on the bolt stop...which might have been LocTited in place at some point, compounding the issue.

I like the through-pin on the 700 side bolt release conversions...keeps all the options open for servicing.

Good shootin' -Al

 

[clowdis]

The 1/16 and .050 hex wrenches in Chinese made Allen wrench sets fit the sockets pretty poorly and it's easy to mess up a screw or the wrench trying to remove a tight screw. IF you can find some American made Allen wrenches buy those.

 

[LVLAaron]

Congrats Al. I'm sure that was a frustrating one to have sitting on the bench.

 

[AlNyhus]

The 1/16 and .050 hex wrenches in Chinese made Allen wrench sets fit the sockets pretty poorly and it's easy to mess up a screw or the wrench trying to remove a tight screw. IF you can find some American made Allen wrenches buy those.

The Brownell's bit in their MagnaTip Super Set is the best fitting I've found. You can get the 1/16" bits seperately, #185-00/5221. One of these is always in my range box.