What type of Drill do I need?

[brstevns]

Need to drill a couple of holes in a Harden Steel 98 Mauser bolt. What type of drill bit do I need, Cobalt, Carbide etc. Already burned up a couple of HSS type bits

[Winger Ed.]

I'm a big fan of Cobalt drill bits & plenty of oil.

They're about as hard as Chinese Algebra, and have always done a good job for me.

Without knowing what ya gotta get through, its kind of hard to make a specific recommendation.

[roysha]

Well, I don't know about anyone else, but I think a bit more information would be very helpful, such as, why, where, size, etc.

[georgerkahn]

I have had poor results drilling hardened steel. You may wish to check machinery handbooks to determine the correct speed for the size you're planning on drilling, as a first. The correct r.p.m.'s of the drill bit -- which varies by diameter is important. Also, a good cutting oil helps immensely in both keeping cutting edges cool, and enabling them to do their work, cutting. I generally make a modeling clay "dam" around spot, using LOTS of oil -- my favourite is a product called, "Tap-It". Most sadly, you may (I hope not) be doomed for failure in your attempts, unless (which opens up a gigantic can of worms, so to speak) you heat your work-piece to anneal it -- get it soft enough to drill; and then, hopefully re-harden it. I've had better success with solid carbide screw machine bits from an outfit on Long Island, New York, called Drills & Cutters -- https://drillsandcutters.com/carbide-stub-drills-screw-machine/. The screw machine bits are really much shorter than jobber bits, and thusly -- in your drill press chuck -- are prone to significantly less wobble and truer holes. You may wish to ring them; they have been most helpful to me (hey -- before calling, I'd never heard of "screw machine bits" ;) ).
BEST wishes!
geo

[john.k]

There is a drill that will drill very hard steel......solid carbide rod with a pyramid shape point.Run at high speed ,it basically melts out the steel and pushes it aside,not suitable for deep drilling......If these are not suitable ,then I suggest EDM,which will hole anything even solid carbide.

[EDG]

What are you drilling and how large a drill do you need to use?

You may need to spot anneal or use a carbide drill.
If you spot anneal you might be able to get by with a cobalt drill.

The big problem is if you have to ask this question you are not likely to have the skill needed to successfully drill something hard. It is tricky to get it right.

[country gent]

Heres some info that might help. HSS cobalt may cut it but wont last long. Carbide will cut it but you need a pretty good spindle for it to hold up, chatter run out vibration all will damage carbide. Speeds and feeds are very important. I have drilled 60 RC die inserts with carbide spade drills with good results, but this was done in an end mill or jig bore machine for location reasons. AN EDM will do the job nicely but is slower than drilling., unless its a action only there are few edms with a tank that can hold a barreled action. The submersed flush also makes it a messy way.

Most of the 98s were case hardened so its getting thru the first .060 or so thats the hard part. Here the short spade type carbide drill ( solid not soldered end) will get thru. If you want to tap the hole you also need to relieve the cased area with a body sized drill also or taps wont hold up. It can be one and isnt super hard but you do need a solid et up and a goo spindle in the machine. Chips will be fine hot and sharp so be careful.

[PHyrbird]

Jerry Stahl of Bowling Green Ky (deceased) was expert at this. Heat a 7/16-1/2" plug cherry red it will "spot" anneal the location of the drill & tap. Of course Before heating it's a good idea to shape the plug to the surface to be annealed. Let the plug set on the spot till it is room temperature then reheat for the next spot. One plug can be used time after time. As I recall he just used High speed bits & regular taps after annealing. No sweat.
If you feel need test the annealed spot with a file, cuts easy, you're good.
One important point, spot anneal has Very minimal effect on the strength of the part.:guntootsmiley:

[MaLar]

Jerry Stahl of Bowling Green Ky (deceased) was expert at this. Heat a 7/16-1/2" plug cherry red it will "spot" anneal the location of the drill & tap. Of course Before heating it's a good idea to shape the plug to the surface to be annealed. Let the plug set on the spot till it is room temperature then reheat for the next spot. One plug can be used time after time. As I recall he just used High speed bits & regular taps after annealing. No sweat.
If you feel need test the annealed spot with a file, cuts easy, you're good.
One important point, spot anneal has Very minimal effect on the strength of the part.:guntootsmiley:

He wants to drill the bolt not the receiver.

[brstevns]

Was planning or hoping to install a Savage bolt head on a Mauser Bolt

[pietro]

Was planning or hoping to install a Savage bolt head on a Mauser Bolt

In that case, it might work if both bolts were cut in half...…

I would first accurately measure the length of the stripped Mauser bolt.

I would then cut the Mauser bolt about 1/2" ahead of the bolt handle (with a heat sink in the rear threads to protect the cocking cam there).

I would then cut the Savage bolt also somewhere ahead of the bolt handle (with a lead heat sink wrap around the locking lugs), at a spot that would make the hybrid bolt the same length as the original Mauser bolt after welding.

After the two pieces were welded together at the cuts (with heat sinks on both ends of the hybrid), I would then check/adjust headspace.


Then I would kick myself for even thinking about doing that...………………………………….. [smilie=b:


.

[brstevns]

It is a neat way to make up a bolt to feed the .223 in a Mauser Action. That Why! :drinks:

[30calflash]

A place I worked at years ago converted SA Rem LH 700's to 223 by bushing the bolt face and using a Sako extractor. They always worked fine, never heard of any issues.

You're in new territory with the Mauser though. You may want to get a few bolt bodies for practice.

[PNW_Steve]

I use 3/16" drill bits quite a bit. I have found decent bits in quantity online. They offer them in various sizes.

The ones that I am using are cobalt bits that come in a10 pack from Amazon. It may take a few of them to get the job done.

As previous posters mentioned: make sure that you are using the proper speed and lubricant. I have switched from 3in1 oil to a water-based cutting and drilling lubricant from NAPA. Cuts and cools well, cleans up easily and is cheaper.

I would recommend a decent drill press as well.

I drilled an Austrian Mauser action for a scope mount about 30years ago. Today I have a drill press and quality bits. If I needed to complete that task again I would not hesitate to visit my local gunsmith.

[Traffer]

I have used Tungsten Carbide drill bits before. They will drill just about anything. There are several types of these. Solid carbide, where the entire bit is carbide. Spade tipped with a flat tip kind of like an arrow head. Carbide tipped that are sharpened for cutting metal. And Carbide tipped masonry hammer drills.
Of these kind I have not tried the spade tip units, but have used all the others. One thing that I have experienced is that they are not as precise as HSS bits. If you need an exact sized hole you are better off drilling a hole a bit smaller and using a carbide reamer to take it to the actual size.
I like cheap stuff so what I have ended up doing is learning how to sharpen the cheapo carbide tipped concrete hammer drill bits to cut steel. They can be sharpened with diamond wheels. There are cheap diamond wheels that are for use on dremel type tools. That is what I use.

https://youtu.be/bZUEs3FLhUo

[Drm50]

I’ve used Tungsten Carbide bits mostly. I use to buy from Brownell but lucked into TRW bits to last a life time.
I have drilled 98 actions for scope mounts and 4 holes is the end of the bit for drilling hardened actions. I do use a smaller bit to hole action then run the 31 through it. Only because I have hundreds of small bits In the TRW stuff. After holes are drilled then you must be very careful not to twist a tap off. I think heat of drilling holes softens metal around hole some, but it’s still pretty hard. If I had to buy bits it would be from industrial supply and only buy sizes you need bulk. Drill bit sets are a waste. The shortest bit is best for most gun projects.

[oconeedan]

As a knife maker, I have to drill hardened steel once in a while. I use carbide bits, they are short and expensive. My method, is to peck at it. Drill press only, you will break it if you use a hand drill. Use cutting oil. I drill in short, interrupted pecks, allowing all chips to clear. If you get it hot you are making things more difficult. If you use too much pressure, the bit will break. Carbide bits don't like to bend. A sharp, carbide bit, will get the job done.
Dan

[James Wisner]

" It is a neat way to make up a bolt to feed the .223 in a Mauser Action. That Why "

OK, you did not say WHICH Mauser type of bolt you want to convert.
A 93, 94, 95 or a Swedish or a M98 ?? big differrence between them all.

Another option is to buy the back half of the FN bolt bodies that Sarco has,
They are set up for the M98, nice handle, and third lug, but the front section of the body is oversize at .720 for a reason.
Then machine a new bolt head and baffle to fit onto the projection the bolt has all ready, attach or pin and there you go.

You can recut the rear section to work on the 93 - 96, and the thread timing is correct for the Swede sleeves.
Make a new bolt head and baffle, pin and off you go to the fun part of the conversion, that of making the shaped magazine insert to go into the old trigger guard to feed the 5.56 or 300 BO.

Yes its doable and I am in the middle of the same type of conversion once the Savage bolt head gets here so I can copy it to make new bolt heads to fit onto the Sarco FN Mauser bolt bodies

JW

[akajun]

This is an operation that needs to be done in a lathe or mill, hence why would you need a drill? You need a carbide indexable boring bar set up.

[EDG]

If this is changing the bolt face drilling is not the way to go. You want to bore the bolt face out with a small carbide boring bar. You can even grind a piece of brazed carbide to bore the shallow recess needed for a bolt face bushing.

I have never bored one out but I have faced them off to clean up light pitting.

[Dieselhorses]

As a knife maker, I have to drill hardened steel once in a while. I use carbide bits, they are short and expensive. My method, is to peck at it. Drill press only, you will break it if you use a hand drill. Use cutting oil. I drill in short, interrupted pecks, allowing all chips to clear. If you get it hot you are making things more difficult. If you use too much pressure, the bit will break. Carbide bits don't like to bend. A sharp, carbide bit, will get the job done.
Dan

What he said^^^^^^

[brstevns]

If this is changing the bolt face drilling is not the way to go. You want to bore the bolt face out with a small carbide boring bar. You can even grind a piece of brazed carbide to bore the shallow recess needed for a bolt face bushing.

I have never bored one out but I have faced them off to clean up light pitting.

No lath, so not much of a choice

[brstevns]

" It is a neat way to make up a bolt to feed the .223 in a Mauser Action. That Why "

OK, you did not say WHICH Mauser type of bolt you want to convert.
A 93, 94, 95 or a Swedish or a M98 ?? big differrence between them all.

Another option is to buy the back half of the FN bolt bodies that Sarco has,
They are set up for the M98, nice handle, and third lug, but the front section of the body is oversize at .720 for a reason.
Then machine a new bolt head and baffle to fit onto the projection the bolt has all ready, attach or pin and there you go.

You can recut the rear section to work on the 93 - 96, and the thread timing is correct for the Swede sleeves.
Make a new bolt head and baffle, pin and off you go to the fun part of the conversion, that of making the shaped magazine insert to go into the old trigger guard to feed the 5.56 or 300 BO.

Yes its doable and I am in the middle of the same type of conversion once the Savage bolt head gets here so I can copy it to make new bolt heads to fit onto the Sarco FN Mauser bolt bodies

JW

Working with a 98 SR . Curious do you know what size hole those bolts have drill thru them?

[bangerjim]

A am fortunate to have a large set of solid carbide twist drills and that is what I use for hardened steel drilling on my projects......when I cannot soften the item 1st and drill normally and then re-harden.

CAUTION>>>>>>>>>>>>>>>solid carbide drills are extremely hard.....and break VERY easily! Only use them in a firm, rigid, no-play drill press or milling machine!!!!!

Good luck with your holes. Mabe check locally for a high quality machine shop or tool & die shop that will do it for you. AND............guarantee their work!!!!!!!

banger

[akajun]

No lath, so not much of a choice
Then I doubt you have a Mill or heavy duty drill press needed to use a carbide drill without breaking it or with the precision needed to keep it straight.

[HollowPoint]

I lightly skimmed through most of the previous replies so pardon me if I offer a suggestion that's already been put forth.

Back when I was doing some work on my K31 rifle I wanted to drill some holes in the side of the reciever but the metal on the reciever must be made of kryptonite or something cause none of my expensive drill bits would even put a scratch on the surface. (I'm aware it's the bolt you're trying to drill into but it's metal none the less)

At one point I laid my reciever on my lap as I attempted to get a hole started with what I thought was the hardest drill bit I could buy. The cutting tip seemed to be catching at one point so I pushed down a bit harder only to have the searing hot drill bit slip over the side of the reciever and into my thigh. It went into my thigh about a half-inch before I was able to stop the downward momentum. That drill bit had gotten so hot from just spinning and spinning on the surface of my K31's reciever that when I drilled into my thigh it didn't even bleed. I think it cauterized the hole in my thigh as it was sinking in.

It took that episode of ignorance on my part before I inquired of some of the other home gunsmiths online about how to go about this. Several of the replies I got were similar to the ones posted here. Some suggested "Spot-Annealing" others suggested stuff that I can no longer remember but the suggestion I eventually used was the one that mentioned a certain type of drill bit called a "Hi-Rock" drill bit.

I'm not kidding. None of my better drill bits would even scratch the surface of the metal of my reciever. I bought one of the Hi-Rock drill bits in the size I needed and it cut through the hardened metal of my K31 reciveer like a sharp knife through hot butter. Then I had to tap the holes I'd drilled. That brought about another dilemma but, that's where the spot annealing came in. Anyway, if it hasn't already been suggested or if you haven't already tired it, you might look into buying a Hi-Rock drill bit.

HollowPoint

[brstevns]

I lightly skimmed through most of the previous replies so pardon me if I offer a suggestion that's already been put forth.

Back when I was doing some work on my K31 rifle I wanted to drill some holes in the side of the reciever but the metal on the reciever must be made of kryptonite or something cause none of my expensive drill bits would even put a scratch on the surface. (I'm aware it's the bolt you're trying to drill into but it's metal none the less)

At one point I laid my reciever on my lap as I attempted to get a hole started with what I thought was the hardest drill bit I could buy. The cutting tip seemed to be catching at one point so I pushed down a bit harder only to have the searing hot drill bit slip over the side of the reciever and into my thigh. It went into my thigh about a half-inch before I was able to stop the downward momentum. That drill bit had gotten so hot from just spinning and spinning on the surface of my K31's reciever that when I drilled into my thigh it didn't even bleed. I think it cauterized the hole in my thigh as it was sinking in.

It took that episode of ignorance on my part before I inquired of some of the other home gunsmiths online about how to go about this. Several of the replies I got were similar to the ones posted here. Some suggested "Spot-Annealing" others suggested stuff that I can no longer remember but the suggestion I eventually used was the one that mentioned a certain type of drill bit called a "Hi-Rock" drill bit.

I'm not kidding. None of my better drill bits would even scratch the surface of the metal of my reciever. I bought one of the Hi-Rock drill bits in the size I needed and it cut through the hardened metal of my K31 reciveer like a sharp knife through hot butter. Then I had to tap the holes I'd drilled. That brought about another dilemma but, that's where the spot annealing came in. Anyway, if it hasn't already been suggested or if you haven't already tired it, you might look into buying a Hi-Rock drill bit.

HollowPoint

Thanks Will look that up

[jonp]

I've had luck making a water based drilling fluid with Ballistol

[brstevns]

Then I doubt you have a Mill or heavy duty drill press needed to use a carbide drill without breaking it or with the precision needed to keep it straight.

Sometimes, we must say a prayer and work with what we have.
:drinks:

[Slugster]

Carbide bit. High speed. Do-Drill from Brownell's or Tap Magic for cutting fluid. Job is best done in a mill, but a drill press will do in a pinch IF it has no runout in the spindle bearing. Carbide bits don't bend, they break. Good luck.