Best way to true receiver lugs?
- Thread starter Mram10
- Start date
jackie schmidt
New member
The only sure proof way to true the action abutments is to set the action up so the bolt Raceway runs as true as possible and single point face them.
The first thing you need to determine is do they need truing. And if they do, take as small amount off as possible.
The first thing you need to determine is do they need truing. And if they do, take as small amount off as possible.
GeneT
Active member
Use a boring bar and some sort of fixture that will let you dial in the receiver both axially and lineally. You could use something like this: https://www.youtube.com/watch?v=xNhZnpSrMVA or something like this: https://www.youtube.com/watch?v=vFiLbeeZBx8 . (Probably a few other ways to do it, but those should give you the idea of what you need.)
GsT
JerrySharrett
Senile Member
The last dozen or so Ren 700's I've done only need lapping/ Lap in to full contact (80% or better) with some 200-350 grit ALMINUM OXIDE compounds, then finish with 400 or so grit ALUNINUM OXIDE lapping compound.
Don't ever use something like Clover valve lapping compound or any Silicon Carbide grit. Aluminum Oxide is softer and doesn't embed into the actions steel, with Silicon Carbide the grit is hard enough it will embed into the steel.
Keep in mind that after bolt lugs are fitted together they will need to be lubed with a good bolt grease often or they will gall....not good.
,
Don't ever use something like Clover valve lapping compound or any Silicon Carbide grit. Aluminum Oxide is softer and doesn't embed into the actions steel, with Silicon Carbide the grit is hard enough it will embed into the steel.
Keep in mind that after bolt lugs are fitted together they will need to be lubed with a good bolt grease often or they will gall....not good.
,
Jerry,
How do you determine if lapping will suffice? Do you look at the wear pattern on the lugs, or do you check it with blue?
Justin
Mram10,
The link below explains how I do it.
http://benchrest.com/showthread.php?91625-Action-Truing-Justin-Style&highlight=
Hope it helps.
Justin
JerrySharrett
Senile Member
On most blued actions you can see the cleaned up lugs on the action lugs. On SS actions sometimes I use Prussian blue or a magic marker.
.
Does anyone use Dykem any more?
With a paint brush or sprayer.
When I stopped working at a place with an extensive metal shop about 15 years ago they had mostly switched to using markers.
Like the huge ones the graffiti guys use that stored in a pint can of fluid.
GeneT
Active member
I use Dykem frequently, but only for marking out work. Dykem is great for lay out but for testing engagement (like lug mating) it's just too durable and won't wipe off well enough - that's where prussian blue (or lipstick, or inletting black, etc) are called for.
GsT
Dave Tooley
Active member
When I first started smithing many many years ago there was none of the tooling we have now. I made a piloted lap out of aluminum. The pilot extended through the action. I put it in a drill press and would hold the action in my hand. Lap away for awhile, put the lap between centers and true it up every so often and keep an eye on the lugs. You can learn a lot going slowly.
brickeyee,
I use Dykem frequently for laying out work. I've also used big, fat Sharpies as well. When I've set up to turn something in the lathe (think first pass), and I only need to take a wee bit, I'll Dykem the part, which makes observing contact between the tool and the part a whole lot easier. Sharpies work for this as well. I've always used Prussian Blue to check lug contact, or any other thing I might be checking for contact on.
Per my father, the retired machinist, another use for Prussian Blue is to apply it to the back of handles on equipment that is to be used by co-workers and hope they rub their face shortly thereafter. Machine shop hijinks...
Justin
MilGunsmith
Member
I use the sharpies, but also have a homemade kerosene soot lamp for fitting parts together.
MilGunsmith,
Kerosene soot lamp...now that is old school! I would imagine it is a more accurate way of checking fit than Prussian Blue, as it is thinner and more consistent. I gotta get one...
I've always wanted to be a fly on the wall at Purdey, David McKay Brown, Holland & Holland, etc., and watch them fit parts and stocks using a kerosene lamp and hand tools. I've read that for final fitting of the barrels to the breech face on a SxS shotgun, they're trying to fit to the point where closing the gun results in the barrels removing half the layer of smoke on the breech face. Helps explain the price tag...
Justin
jackie schmidt
New member
History has shown that humans can achieve anything if cost and time are not a restraint.
The Egyptians proved this over 4000 years ago in the construction of the Great Pyramid.
Jackie,
You are absolutely correct.
But given my druthers, I'd rather have a David McKay Brown SxS than a pyramid!
Justin
JerrySharrett
Senile Member
Sight blacker. I used one for years for pistol sight blacking. The soot is too thick and not enough adhesion for rub testing/
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MilGunsmith
Member
Easy enough to make, piece of cotton clothesline, cuttoff cartridge case soldered to a jar lid. Or find an old oil lamp at a garage sale or flea market and use the bottom half.