This is a set of 10 of the No.4 mounting kits (4-40 Fillister Slotted Head with brass press-fit ferrule and nut).
Since the most popular length is 1.5-inches (also the longest available) I keep these ready to ship all the time, and can send it
to you a bit faster than the other sizes. The 1-1/2 inch long size screws are also the most "universal" since you can cut them to any shorter
length with a pair of metal cutting pliers or an electrician's plier with the threaded screw holes for adjusting screw lengths.
If you don't specify any other length, I'll send the default 1.5-inch option. But you are welcome to select any other length that is shown here. If it isn't shown, I do not
have it. The press-in ferrule and nut are designed to fit properly into a 1/4-inch hole.
A .250-diameter step drill or a countersink reamer with the pilot replaced by a 3/32 to 1/8 inch drill bit works
well to make the hole. Or you can drill a 1/4 inch diameter hole just deep enough so the nut or ferrule is slightly below surface but leaves at least .070 inches of
material to the other side. Then
drill the clearance hole for the NO.4 screw (1/8 inch is big enough). Finally, you can (optionally) square up the bottom of the
1/4 inch hole with a flat ended end mill or countersink reamer using a pilot that fits into the clearance hole.
That spreads the force out on the grip material more evently than if you leave the normal conical drill hole.
If you need a tool bit to quickly make both the .250 main hole and the No.4 clearance hole, email me and I can make one for you. The price varies with the times, since I just buy a 1/4 inch
piloted straight shank reamer and instead of using a pilot, I cut off a high speed steel screw machine twist drill so it projects enough to clear gun grip
thickness for any practical gun grip, and install it in the reamer. The bit is held in place with a set screw. Imports are much cheaper but often the set screws are
not in the right place or tightening them pops a hunk of metal out of the reamer because it is not correcctly tempered. Just my experience with the lower priced tools.
I use the more expensive but longer lasting USA made parts, not imports, and add their cost to a half hour
of labor, plus the shipping. Usually the whole thing comes to somewhere between $35 and $50. The cost is like the catch of the day: depends on what the current tooling market price is for the parts.
Naturally, if you are not doing a lot of grips it isn't worth the cost. If you are, it saves you a lot of time. Same thing I use.
You can also make a simple flat drill with the two diameter profile,
which is what some gunsmith supply shops sell. But those don't generally last as long and don't always cut as precisely. They only have one cutting edge, compared to the
chucking reamer and twist drill. So the edge wears down more quickly and can chatter more easily. But if you are only mounting one or two grips, it's good enough.
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