help with pillar bedding a boyds laminate stock !!!!!

S

Springfield03a3

Inactive
Hello all I have been getting alot of information from everyone on this site and have a question .. im going to attempt to pillar bed by marlin x7vh in 22-250 into a boyds thumbhole stock.. I am very mechanical inclined and am a machinist by trade so making the pillars is no problem for me my question is what epoxy should I use to glue the pillars into the stock and about how much clearance should I give between the pillar o.d and the size of the hole I put in the stock were the pillar will be glued ? Any help is greatly appreciated thanks everyone .. hopefully some epoxy I could get locally as well so I dont have to pay an arm and a leg for shipping lol
 
Drill the holes about 1/32" larger than the pillars. This will allow some resin around the pillars.

Cut the pillars to the exact length needed.

Use epoxy resin (as used in aeronautic or marine applications) as opposed to polyester resins (as used in automotive applications). Good resins can be found in many places, but you want slow cure resins (90 minute to 24 hours cure time, no 5-minute cure resins). Devcon, West Systems, Bisonite are some of the best, but others will work.
 
Don't forget to cut "lock grooves" in the outer surface of your pillars. I also take a Dremel burr and cut a couple of circumference grooves in the stock holes for extra gripping.
 
For the devcon should I use the 10110 plastic steel ? Or something else ? And yes I have thought about roughing everything up to give it a better bite in the stock and the steel and making the grooves in it .. and thank u for the link too as well
 
Im also thinking about making the pillars out of some good stainless because weight is not an issue and the pre hard stainless would be much more stable and crush resistant than alluminum
 
For the devcon should I use the 10110 plastic steel ?
Click to expand...

10110 is probably most widely used. Scorch mentioned others, I've also used JB Weld, and McMillan (IIRC) uses Marine-Tex. Most any epoxy will have the requisite tensile and compressive strengths- what's important is zero shrinkage when cured, so that the female "impression" of the action remains perfect.

You're a machinist, so you're familiar with a counterbore- it's the most precise way to open up the holes for pillars, just measure the pilot size you need and go 1/16" oversize your pillar OD as Scorch said.

Stainless will certainly work, but your concerns about "crush resistance" really aren't relevant as you're only talking 55 or 60 in. lbs. (typically) for torque values.

If you go a step further and bed the receiver, this is the best resource I've ever come across on "how to do it":

http://www.6mmbr.com/pillarbedding.html
 
For pillars I have used:
3/8" O.D. brass tube...........dissimilar metal worries.
3/8" O.D. stainless tube.......difficult to machine
3/8" O.D. 1010 steel tube...... probably good enough
G10 epoxy from McMillan Master.... did not use
1/2" O.D. 6061 Aluminum alloy round stock... probably good enough
5/8" O.D. 6061 Aluminum alloy round stock... probably good enough
3/4" O.D. 6061 Aluminum alloy round stock... probably good enough
Hogged it out of blocks of 6061 Aluminum .... lots of work

For epoxy I have use Devcon steel putty and Devcon liquid steel.
I like the putty better.

For the shape of the pillar for round bottom receivers, I like to use a boring bar to match the radius of the top of the pillar to the radius of the bottom of the receiver.
But not a perfect match.
The radius on the top of the pillar should be smaller, but not so much smaller than the clamping force of the screw does not make them fit.

This pre load on the pillar ears is to grip and position the action better to couple more of the rotational force of recoil from the action to the stock before the bullet exits the barrel. This is similar to the force multiplier effect of a V block.
 
Radiusing is a good idea (I've done it with a flycutter), but in the linked article the author feels it's just as effective- and I would agree- to just let the epoxy form that radius above the pillar flat. Does save a lot of work, and the epoxy would serve the same purpose of cradling the receiver correctly. Nothing wrong with doing both, but the pillars need to be precise if radiused or they'll bear unevenly on the receiver.

JMO, screw clearance is irrelevant (I cut the ones I sell for the MN intentionally oversizing the ID to allow for variances in fitting by the customer) as long as the action screws don't make contact. I've seen some used just thousandths larger (ID) than the screws, there is greater risk of the action screw making contact if the clearance is too tight, and I've never understood what could be gained if there's .005 clearance, or .05...
 
Wagner has had a web site for over 10 years showing how to make pillars.
He wraps tape around the screw to keep them centered. He takes the tape off after the epoxy is hard.

http://www272.pair.com/stevewag/turk/turkbed2.html

When working jet engines, the mechanical engineers I dealt with were so smart that I never spoke to them about tolerance build up. But in no moving parts electronic boxes it came up again and again. Anyone can make a dimensioned drawing. Calculating the tolerance a dimension as a multi person project is sometimes like asking how many angels can dance on the head of a pin, as esoteric effects are sorted.
What is best is if there is a strong willed person who will growl in anyone's face, "It is %$# good enough!"
 
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