How they do that???

[deadin]

I'm a gun collector and for years I've known that some of the higher grade European guns from the late 1800's had all of the screw slots lined up fore to aft when assembled. It's only since I've started messing around with machining that I realize I have no idea how they manage to do that.

Any hints????

 

[ksouers]

Um, cut the slots after the screws are in??

Really. Have no idea.

 

[black85vette]

Interesting. Since they were hand made I wonder if the screws could be interchanged or if each was fitted to its spot? Still, a nice touch.

 

[deadin]

Um, cut the slots after the screws are in??

I thought of that, but how do you torque a screw in with no slot?? ???

 

[vlmarshall]

What about adjusting the countersink depth to align the slots? Then, umm...maybe filing the heads of the screws to sit flush? I dunno, I'm just guessing, too. ;D

 

[shred]

If you were consistent about the orientation of the tap at the start, the holes should index screws consistently. Then you could by trial and error, determine where to cut the slot on screws held in a similar fixture. You could also tickle a little off the underside of a screw head if needed with a holding fixture.

Another option would be tall-headed screws with extra meat on the head, like say a SHCS or carriage-bolt-- torque 'em in, mark on the side where the slot should be, remove and turn off the excess head and re-slot in the correct spot.

All speculation here too.

 

[Tin Falcon]

I am not sure how it is done but I have heard of some of the high end model engineers doing the same. A bit of math and details of where the threads start would do it me thinks but I am happy if the engine runs I have not worried about aligning bolts or screw slots.
Tin

 

[shred]

I got curious and I poked around a little on Google and came up with the following article on 'Timing Screws'

http://www.shootingtimes.com/gunsmithing/ST_timingscrews_200812/

Turns out at least three of the methods we've speculated are in there. ;D ;D

 

[deadin]

Neat!!!
And to think that all three methods were thought up here! ;D

Thanks guys!!

 

[phlegmatic]

Im trained as a gunsmith, theres lots of need for timing treads in gunwork; like when u thread on on a barrel for example. All you need too know if the pitch of the thread to do the math, as the article explains!

One thing that ruins your day is when u overtighten a screw thats part of an engraved pattern, then you need to shim it or make new if its worth the cost...