Proper way to install and remove locking shoulder

[Nwfal]

What is the proper way to remove or install locking shoulders. After using the hammer and punch method I think there must be a better way. Mine always get some marks even when using brass punch. Is a arbor press the way to go? If I do get the arbor press what other uses are there for it.

[S.Kargoh]

You're doing it wrong!!! Use your thumb as a cushion, and you don't get any marks.

That's what I did. Ouch. http://www.fnfal.com/forums/smile.gif

[FootLongCuban]

I use a large pointed punch. (Craftsman) The tip of the punch fits neatly into the small hole on the big end of the locking shoulder. Place the receiver on a mouse pad up on my vise and whack it into place being carefull to keep it perfectly straight. If it starts to turn on you just open a small adjustable wrench to size and give a light turn to correct direction.

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"Your village called, they're looking for you."

[juanni]

A 20 ton hydraulic press works wonderfully. I probally use only 5 tons to press locking shoulders though. A press is essential for pressing in AK barrels, should you want to diversify. Other uses, with properly shaped inserts a barrel vise. The main thing I use it for is pressing bearings mostly in automotive applications. Beating precision bearings on and off is impossible and hell on the precision aspect.

[Nwfal]

I went crazy and bought 1/2 ton arbor press for 39 bucks. used it to press out a locking shoulder in 1 minute with no scratches. Hope i can find some uses for my cars. My collection of tools grows every day,where do i put them all?

[CJF]

Two suggestions -

1) Use your vise for pressing the shoulders in. Just be sure to pad them properly w/ wood blocks or something else soft so that you don't mar the receiver. (Someone else came up w/ this one.)

2) For removing the shoulder, take a roll of duct tape and lay it on its side. Rest the receiver on top of central hole and use your pin punch or whatever to drive out the shoulder. I also put duct tape around the hole just in case the punch slips off the shoulder - hasn't happened yet but I'm hoping this might keep the punch from sliding over the receiver side and creating a huge gouge. Same principle as using a bench block w/ various sized holes. (If you can't fix it with duct tape, it ain't broken.)

[FNfreak]

Ahhh...Duct Tape...GOD on a roll!

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""[W]hen the resolution of enslaving America was formed in Great Britain, the British Parliament was advised by an artful man, who was governor of Pennsylvania, to disarm the people; that it was the best and most effectual way to enslave them; but that they should not do it openly, but weaken them, and let them sink gradually. . .

-George Mason, Virginia's U.S. Constitution ratification convention, 1788

[Nwfal]

ah, but the last 2 Sa kit I got had no holes in the locking shoulders. they are flat on both side. The punch tends to slip when being stuck. now I wll just press them in.

[TooTech]

Put the locking shoulder in the FREEZER for 15 minutes. I got this tip on this board and it really helps.

Of course, when you get the shoulder out of the freezer, have everything else all set up so you can start hammering ASAP as it will warm (and expand) quickly.

[BBBBill]

Whichever method you use, when you are about half way, stop & verify that the leading end is still lined up with the hole in the left side of the receiver. They will drift out of alignment during installation.

[Blood of Tyrants]

Originally posted by TooTech:
Put the locking shoulder in the FREEZER for 15 minutes. I got this tip on this board and it really helps.

Of course, when you get the shoulder out of the freezer, have everything else all set up so you can start hammering ASAP as it will warm (and expand) quickly.

Get a can of keyboard duster from Walmart and invert it while you spray. This will cause the spray to come out as liquid and it will be much colder than from the freezer.

Also I use a scrap hardwood board on top of the locking shoulder and hit it with the hammer to pound the locking shoulder in. No marks whatsoever.

[This message has been edited by Blood of Tyrants (edited March 05, 2001).]

[Fritz]

I just finished determining the correct LS size for first FAL. (Thanks to all who have gotten me this far). I thought I was almost done until I tried to install a LS in my Imbel receiver. I know it is supposed to press fit, but that hole looks too small! The LS measures .298 (I mean the diameter on either end, not the flat part) and the hole in the Imbel is .288. That's gonna take a _lot_ of pressing. Am I missing something?

[Nwfal]

are you sure you don't have a oversize locking shoulder? Mine start with a little effort at the start but the hard part is at the end when at the bottom. Thats where the pressure is really needed.

[Fritz]

Originally posted by Nwfal:
oversize locking shoulder? FritF

I have two Imbel receivers and two STG-58 kits. The shoulders came with the STG kits and both measure .298 and the holes both measure .288. I don't think you can press fit two items which differ in size by .010.

We tried to shrink the LS by putting them in liquid nitrogen, which reduced diameter .0015 -- not nearly enough.

Also, checked the fit of the flat part of the LS and it will not fit depression machined into the reciever.

Would someone measure their LS and/or reciever hole and tell me if they are the same as mine? or offer some other explanation?

Thanks again.

[RonB]

Fritz,
How did you measure the hole in your receiver?

[Fritz]

Originally posted by RonB:
Fritz,
How did you measure the hole in your receiver?

Dial calipers.

[RonB]

The calipers have a slight flat on them. The hole may be a little larger than you think. If you can, get some sort of taper pin and stick it in the hole, mark it where it contacts the receiver, and measure the O.D. at the mark. If you can, get a #L drill bit (they are .2900 dia.), and see if it will go in the hole. HTH

[rezman]

Fritz, I had the same problem on my first kit. I can't remember the dimensional difference I came up with but the LS was a VERY tight fit. I ended up using a cratex tip on my dremel tool to lightly polish (NOT grind) the parkerizing from the holes in the receiver. Used a little gun oil to facilitate progress and drove that puppy home. Worked for me. Hope this helps.

[BBBBill]

You can't accurately measure a hole with dial calipers for the reason stated earlier. A hole gage is the best way if you can get one. Looks like a half ball on the end of a shaft, split down the middle. There are some oversize diameter LS for holes that have been stretched/worn from use, but those that come with the kits have all been standard that I've handled. Before installing, turn it over & trial fit the head/locator tab in the receiver recess. LIGHTLY dress it on the edges if needed. The rest is as stated above.

[Fritz]

Thanks all. I will measure again tonight.

[W.E.G.]

The FIRST thing to do is make sure the dogleg of the locking shoulder will drop-in to the recess of the receiver. It really sucks to get the shoulder driven-in 95% of the way, only to discover that the dogleg won't fit in the recess.

Next make sure you don't have an oversize shaft on your locking shoulder. The normal size is .297" If you have anything fatter, you should forget about using it on a new receiver. A lot of recently-imported L1A1 kits have oversize shafts on the locking shoulder.

Before you start hammering, you need to be ABSOLUTELY SURE that the dogleg is oriented so that it will drop into the recess when it reaches the receiver.

I like to put some grease on the locking shoulder, and some grease on the hole. Then I hammer it in with a brass punch. Be sure to hammer it ALL THE WAY IN. If you are resting the receiver on a wood block during the hammering process, you will need to drill a large enough hole in the wood block to allow the shaft of the pin to protrude from the receiver as you hammer.

All that freezing business sounds unnecessary to me.