liner drill for 22 rim fire

[country gent]

Im getting ready to grind the pilot on a 5/16 frill to use for installing a couple liners in old 22 I inherited. Ive checked several here and .216 seems to be the number. Am I correct in this.

[kenton]

SAAMI specs for 22lr call for .217" minimum bore diameter so .216" seems reasonable for the pilot.

https://saami.org/wp-content/uploads...2018-06-13.pdf

Chamber drawing starting on page 14 according to the document or page 21 according to the PDF software.

[405grain]

In my experience, when using a sharp (brand new) 5/16" extension drill, the existing barrel bore acts as a guide hole. So long as the drill is sharp and both of the cutting flutes are equal, I've had no problems boring 22lr barrels for installing liners without need for a pilot on the drill. I start the holes with an ordinary 5/16" drill and bore in at least an inch or more so that I won't get chatter and vibration with the extension drill. When a barrel is longer than the drill I bore as far as I can from one end, then reverse the barrel in the lathe and bore the rest from the other end. I've used Redman liners and a Bentz chamber reamer with very good results. I use green Loctite cylindrical adhesive to install the liners. If you have the equipment to grind a precision pilot on your drills, by all means do so. I'm just saying that it can also be done without a pilot.

[country gent]

Im planning on doing it this way to see how well it works out. Im going to setup the barrel in the lath and indicate it in chamber out. Im going to set up the steady rest to support the steady rest an inch or so from end of barrel indicated in to support the drill shank and keep it from springing or bowing. This will be similar to the support on a deep hole drill. I will then drill in with a standard length frill and then the long drill. Im planning on peck drilling .030 and break chips to help keep build up down clear chips every inch or as needed. Black sulfur oil for cutting fluid. When the bore is drilled i will soak it in white vinegar over night to etch it for the best surface for the locktite to grip

[country gent]

Drill is ready for the extension. Pilot is 1" long with a 1/4" x .010 lead in dia is .21685. Drilled a 7/32 hole in Half inch block of scrape then opened it up with the drill, chips were clean and crisp no ragged edges, very good finish in hole. Size of hole is .3135 round and true. Now need to get the order of materials in

[405grain]

country gent: Just out of curiosity, what rifle is this barrel for? When someone goes to the effort to reline a barrel it's usually for a pretty neat rifle.

[country gent]

Dads old 1906 winchester pump. Its got a ring in the chamber from cousins using shorts and bore is rough, but I want to keepthe "history" on the out side.

[John Taylor]

When I first started doing liners about 25 years ago I tried a drill without a pilot, It did not follow the bore. A tool post grinder in the lathe or a spin jig in the mill. The hard part is getting the drill dialed in before grinding. If it isn't true the pilot will be off center and the drill will bore oversize. That's why I started drilling the hole undersize and then ream for a close fit.

[country gent]

Not braking chips often enough and or overloading the drill will cause it to wander also.

Im try to find a junk barrel to do a test drill on.

[gnoahhh]

Why not determine bore diameter with pin gauges, and know exactly what diameter pilot you need?

[country gent]

Basically what I did but between 22 rim fire rifles and pistols I only had 5 to test. Since this is a solid pilot I need it to work across the range.

[Hannibal]

Just a curiosity question. How close to specs are the liners themselves?

I've never had the opportunity to check one so I've no idea.

[John Taylor]

https://pacifictoolandgauge.com/sear...submit_search=

22LR liners are usually .310" from T.J.'s. A 5/16" drill should be .3125". I use Loctite 262 to hold them in. T.J.'s also make 22 liner in 3/8" and 1/2" for 22 cal. The liner should slide in freely with very little gap, I try for .002" clearance.

[jmorris]

That's why I started drilling the hole undersize and then ream for a close fit.

This is what I do for things that need to be precise as well.