Tikka prefit, tenon spec?

[Wannashootit]

Can anyone tell me the major and pitch diameter of the Tikka prefit barrels?

I'm modifying a military receiver to work with Tikka prefits, and want to turn a barrel stub to the correct specs as used to fit Tikka receivers.

 

[OldSoup]

I'm not a prefit guy and haven't had my hands on one. However I have chambered for the Tikka action. I use the class 3 information from the machinists handbook.

Tikka uses a standard 1-16 thread. Looks like a pitch diameter of .9594-.9557 and major diameter of 1.000-.9906.

 

[JBoomhauer]

It’s actually a metric thread, but 1-16 works and is what I have used on mine without issue.

 

[Wannashootit]

Looking for the precise spec.
There's over .008 tolerance in a 1-16 2A thread major diameter and .005 tolerance in PD.

I don't want a situation where tolerance stacking could result in a prefit, not fitting the receiver.

 

[FisherT&C]

Here's what I do for a prefit.

Length of shoulder: .985"
Go protrusion: .136"-.137"
1" x 16 tpi class 2
Over .040" wires: 1.023"
Pitch Diameter: .957"
I recommend 80-90 ft. lbs. torque

When I have a Tikka action in hand I usually get a perfect fit right at the top of the class 2 spec, but I go slightly under for a prefit to compensate for any variation. Take off barrels are usually right in the middle of class 2 spec.

Hope that helps.

 

[OldSoup]

Looking for the precise spec.
There's over .008 tolerance in a 1-16 2A thread major diameter and .005 tolerance in PD.

I don't want a situation where tolerance stacking could result in a prefit, not fitting the receiver.

If you follow the specs in the handbook and use quality measuring instruments you will be fine. What you are referring to as tolerance stacking is exactly why the chart in the books exists.

Example..any in tolerance class 3A (external thread) fits any 3B (internal thread).

If you are worried about measuring properly you can get a thread ring gauge go/no go set.

 

[Wannashootit]

Here's what I do for a prefit.

Length of shoulder: .985"
Go protrusion: .136"-.137"
1" x 16 tpi class 2
Over .040" wires: 1.023"
Pitch Diameter: .957"
I recommend 80-90 ft. lbs. torque

When I have a Tikka action in hand I usually get a perfect fit right at the top of the class 2 spec, but I go slightly under for a prefit to compensate for any variation. Take off barrels are usually right in the middle of class 2 spec.

Hope that helps.

Exactly what I was looking for, thanks.