Drilling receiver for Sights

[joecool911]

Anyone have any words of wisdom before I proceed with drilling the receiver on my Rossi 92 454 Casull? I have a drill press, the receiver has a nice flat surface to clamp to the table of the drill press and I ordered the bits and tap from Midway. I will be installing the Williams FP. I will have to remove the bolt prior to drilling. I have the DVD from Steve's Guz for taking the gun apart. I have some pictures from Steve's Gunz with the FP sight installed so I can match up where he installs them.

[Junior1942]

Wisdom #1: take the word hurry out of your vocabulary.

Wisdom #2: you can use too little oil but you can't use too much oil.

Wisdom #3: start out with TWO new drill bits.

Wisdom #4: tap 1/4 turn, then clean. Repeat, repeat. . . .

Wisdom #5: countersink the holes before drilling.

Wisdom #6: fill the 92 receiver with toilet paper or paper towels to catch the chips.

[45nut]

Great Advice there.

[joecool911]

Wisdom #1: take the word hurry out of your vocabulary.

Wisdom #2: you can use too little oil but you can't use too much oil.

Wisdom #3: start out with TWO new drill bits.

Wisdom #4: tap 1/4 turn, then clean. Repeat, repeat. . . .

Wisdom #5: countersink the holes before drilling.

Wisdom #6: fill the 92 receiver with toilet paper or paper towels to catch the chips.

I thank you for your wisdom!

A couple of questions...

What kind of oil should I use for drilling? I have some tapping oil, but no drilling oil.

I have tapped things before...why do you tap and clean so much here...because of the hardness of the steel?

[oneokie]

Reread Wisdom # 1.

[joecool911]

Compressed air work well for cleaning out the tap and treads?

I am not in a hurry here...I still need to order some punches to take the gun apart. But I figure that I might was well learn how to do this, as it seems that more of the guns I buy no longer are drilled.

Have any ideas what speed to drill at? My drill press has a digital read out.

[MtGun44]

You are trying to get the surface speed of the drill the same, so smaller drills
need to turn faster to make the cutting tip move at the same speed (circumferentially)
as a larger drill. Not ultra critical, just make it fairly fast. Big bits go slower, small
bits go faster.

Use a transfer punch to locate the first hole. Drill and tap and mount the sight, then
use the transfer punch to locate the second hole. This almost guarantees that they
will be properly spaced and located. Drill and tap.

If you don't have transfer punches, it is worth buying a set.

Bill

[deltaenterprizes]

The hardness of the metal needs to be considered also in the speed of the drill bit and the material the bit is made from. Cheap Chineese bits may break or dull quickly if driven at too high a speed and a the heat from friction of a dull bit may harden the metal even more. Cobalt is more forgiving than carbide. Oil is used to keep everything cool heat destroys your cutting tool, I use that dark stinky sulfur based thread cutting oil for drilling and taping. A small centering drill, #0 or #1, to spot drill the reciever before drilling will stop the drill from wandering.Light continous pressure on the handle. Do the front hole then the rear hole and then check your alignment. Do it the first time on a piece of scrap.Use a device to support the tap handle while you are tapping,taps are brittle and small ones will snap in a heartbeat.
Measure twice even three times,cut once.

[HWooldridge]

I put a tang sight on a Rossi 92 but I have the luxury of a having a Bridgeport in my shop so it was relatively painless. The steel on my carbine drilled easily but as Deltaenterprizes noted, you really should use a center drill to start the hole. I used a single new high speed steel bit to drill one hole and then started the tap in the chuck (hand power) to get everything lined up. Don't rush - done once slowly is always better than having to make repairs.

[peterthevet]

Ditto on the cobalt drill bits..........expensive initially but cheap in the long run. Use quality American or European drill bits not cheap chinese knockoffs!!! Take yout time, measure once, measure again - think once, think again - go slowly. Dont forget rigid holding of workpiece....stub drills if you can find them/afford them. Goog luck!!

[Junior1942]

Another vote for the cobalt bits. WARNING: they're so sharp they go through soft metal like a hot knife through butter.

[EMC45]

Good advice Junior! Never thought about the paper towel in receiver trick!

[Calamity Jake]

Watch your clamp pressure on the action to drill press table, it's takes very little pressure to bend the action. You should make a slighty oversize hardwood block to replace the bolt with(you can blow the chips out when finished)
After you have finished the tapping be sure to deburr the backside of the holes (if you drilled thru one side)otherwise it may not go back together.

"why do you tap and clean so much here...because of the hardness of the steel? "

To keep from breaking a tap.

If you have drilled all the way thru one side of the action then you can clean less often but DOUBLE CHECK where that drill is going to break thru before you drill, breaking thru into half a rob and half chanel at the same time can break a drill, and tap.

[joecool911]

I am really enjoying all the discussion.

I think I will be drilling where the locking lugs slide up and down, so there should be no issues with varied thicknesses.

[Char-Gar]

I use the sight base as a drill jig. With the sight base clamped in the correct place, I take a drill bit whose shank is a correct slip fit for the hole in the base. I put the bit in the chuck shank down and use it to locate the correct place to clamp the rifle on the drill press table. I double check the alignment and then reverse the drill bit and with the power on just touch it to the surface of the receiver to make a slight crater. It works to keep the tap drill from skiding on the surface just like a center drill. I then replace the bit with the correct tap drill and drill the hole with the sight base still in place. I then tap the hole, clean it and install the first screw. No need for a clamp after than. I repeat for the second hole.

Any kind of cutting or taping oil works fine for drilling. Just use it in abundance and let the tools do the work, don't force the drill bit or try and horse a tap on through. Bad stuff happens when folks don't take the time to do it right.

If you don't have an air compressor, which I don't, you can buy a bottle of compressed air for cleaning computor key boards and it works just fine to blow out the chips.

Packing the receiver with paper towels is indeed a good idea. It will keep you from having to hunt down and remove the chips from inside the receiver.

YOu will probably have to deburr the edge of the exit hole, a couple of stokes with a ceramic stone will do that.

[pdawg_shooter]

I have in the past, and sometimes still do, "crazy glue" scope bases on to make a drilling gig. when done a tap with a brass hammer removes the bases and clean up is easy.

[KCSO]

Only thing I can add to Jr.'s is that if you have one use a tap guide or a center in the press after you drill the hole. The straighter you tap the less likely you are to break a tap. If you hear the tap start to squeak ,quit, the tap is dull and it WILL break.

[waksupi]

Only thing I can add to Jr.'s is that if you have one use a tap guide or a center in the press after you drill the hole. The straighter you tap the less likely you are to break a tap. If you hear the tap start to squeak ,quit, the tap is dull and it WILL break.

I agree. The best way to tap the hole, is to remove the bit after drilling, and use the press as a guide without moving the set up.

[oscarflytyer]

Any additional wisdom if the receiver is a military surplus rifle, such as a Mauser? I have a Swede that is sporterized and cut down. I want to set it up for my younger son. Thanx

[Junior1942]

Any additional wisdom if the receiver is a military surplus rifle, such as a Mauser? I have a Swede that is sporterized and cut down. I want to set it up for my younger son. ThanxMy Mauser, a Turk 38, was easy to drill & tap using a carbide drill bit from Brownells.

[Nora]

I have tapped things before...why do you tap and clean so much here...because of the hardness of the steel?



For the most part it's to just get the cut chips out of the way. If aloud to build up the threads will start galling. As well as increase friction. Possibly also causing the tap to bind. This is the same practice used when drilling a deep hole. drill a little let up to clear the flutes of the metal, then drill some more.

my .02

Nora

[StarMetal]

I was taught when you're tapping a hole you run the tap a little clockwise, then turn it back counterclockwise..then repeat, then you clean it and go at it again. The flutes in the tap collect the chips, you have to clean before the flutes gather too much. I've never had any trouble tapping with this method. I disagree some with if the tap squeaks it's worn out. There are things that can cause a new sharp tap to squeak. Too many to list here.

I too always set the tap up with what I used to drill the holes first, example a drill press. I don't do anything but remove the drill bit and replace it with the tap to insure the tap will be straight.

The 92 Rossi I had in the early 80's had one of the hardest receivers I've seen except for the Jap rifles.

Joe

[HABCAN]

The last thing I am is a machinist, but I have drilled and tapped a lot of receivers for sights. Biggest problem was always establishing WHERE to drill, and preliminary fixing of the base in place, as mentioned by pdawg, has been my solution, although I used 5-minute epoxy vs. Crazy Glue. Once set properly you can then centerpunch through the base holes, knock off the base(s), and have at it.

[Char-Gar]

I have always used machinest clamps to hold the base on the receiver while I used it as a jig. Has worked for me nigh on 50 years.

[JIMinPHX]

As has been said, it is important to use a good quality drill bit (or 2). In my opinion, it it even more important to use a good quality tap. Taps come in many different geometries. The best tapping method depends on the type of tap that you get. If you get a standard 4-flute "hand tap" (the most common type) then the advice already given is correct. If you get something like a spiral point gun tap, then stopping & backing up to clear chips is actually a bad thing to do. If you are using screws with a common machine thread, then you can get taps with just about any geometry that you want. If you are using screws with one of the special threads that is commonly used for sights, then your selection of available taps is going to be very limited.

Regardless of what tap you use, one of the most important things (right along with good lubrication) is to be sure that the tap is lined up straight with the hole. I can not overstress how important this is. Starmetal's recommendation of using the drill press as a tap guide is a good way to ensure this. I would suggest one of two methods. The first is to simply grab the tap in the drill press chuck & then turn the chuck by hand for the first 1-1/2 or 2 turns to get things started straight & then change over to a tap handle to finish the job. The second method is to chuck a short piece of 1/4" round bar & with the drill chuck spinning, file the end to a point around 30 degrees. Then jam this point into the back of the tap handle to keep the tap straight. Many T type tap handles have a hole already there for that purpose. If not, then you can either eyeball it, or add the hole yourself.

[Willbird]

Another vote for the cobalt bits. WARNING: they're so sharp they go through soft metal like a hot knife through butter.

One thing about cobalt drills, they are not as hard as a good HSS twist drill. Cobalt is added to allow the tool to resist heat better. There are not many metals out there that cannot be drilled with a GOOD QUALITY HSS twist drill. I used to drill hundreds and hundreds of holes in A2, D2, M4, M42, 4140HT, S7, and H13 steels with a single good sharp HSS twist drill, then put it away, and the next guy would sharpen it and drill hundreds more.

Many T handle tap wrenches have a center in the back end of them, if you grab a twp the correct size, often a 1/4" or a 5/16" it has a nice ground male center on the back end, just chuck that tap on on the smooth part (not the threads) with the square end (with nit's nice ground male center on it)and you have your tapping center :-). They often hold taps between two female centers to grind them is why they have this male center on the back end.

Before I tapped the receiver if you have not done a lot of small drilled and tapped holes I would take a few practice runs on some odd steel (not hardened) you have laying around.

Older gunsmiths have told me they used a tap ONCE on Springfield receivers than threw it away :-), and this was even after they got around the case hardening in some way.

Bill

[Morrison Machine Shop]

You definitely need to use a drill jig, don't drill or tap without it and don't go all the way through. And use a carbide drill bit. Countersink or spot drill the locations first, you do not want the drill bit to walk.