# How Can I Drill Into Hardened Steel Calipers?



## Jeb1234 (Jun 11, 2016)

I'm trying to mount a cheap Lowe's digital caliper on my milling machine's quill for a quill DRO.

I've gone through 3 drill bits and two hss end mills trying to get a hole for a 8-32 screw.
How in the heck can I drill this stuff?  I'm going with very slow rpms, cutting fluid and trying to put plenty of pressure on the feed but all I'm doing is dulling bits and end mills.

I can't heat it to remove the temper because I don't want to risk damaging the electronics and I don't really want to take it apart if I don't have to.


----------



## dlane (Jun 11, 2016)

What kind of mill is it, Enco sells a kit to fit a caliper to BP type mills .
Got a pic of mill ,


----------



## Jeb1234 (Jun 11, 2016)

It's a Precision Matthews PM935TS.  BP clone.  Here's a stock picture of one.


----------



## talvare (Jun 11, 2016)

I recently did a similar thing for my lathe tail stock. Just used a center cutting carbide end mill and it went through like it was mild steel.

Ted


----------



## TOOLMASTER (Jun 11, 2016)

i just made a mount block with a slot to put it through . hold in place with set screw


----------



## T Bredehoft (Jun 11, 2016)

TOOLMASTER said:


> i just made a mount block with a slot to put it through . hold in place with set screw



That's using your head.


----------



## davidh (Jun 11, 2016)

cobalt drills work well with lube and pressure. . .


----------



## jpfabricator (Jun 11, 2016)

Use a carbide tipped mason drill bit.

Sent from somewhere in East Texas by Jake Parker!


----------



## kd4gij (Jun 11, 2016)

:+1: I use masonry  bits on had steel all the time.


----------



## Jeb1234 (Jun 11, 2016)

OK, after a trip to Home Depot I picked up some Milwaukee cobalt drill bits.  
50 rpm, heavy pressure and light cutting oil...got about 0.040" in before the bit dulled.  Tried a second...no luck with cobalt.

Grabbed an old tungsten carbide tipped masonry bit, took a grinding wheel with a Dremel and dressed up the tip and tried it.
Same rpm, heavy pressure and cutting oil.  Sounded like chewing on gravel, but it cut right through it with pretty little round holes.
This was definitely the hardest steel I've ever had to drill.

Thanks everyone.  I now have a functioning quill DRO.


----------



## randyjaco (Jun 12, 2016)

I just grabbed a pneumatic cut off wheel  cut  with slots in strategic locations and screwed it in place.. 
Randy


----------



## TOOLMASTER (Jun 28, 2016)

pics for my comment above


----------



## yendor (Jun 28, 2016)

Dremel make Diamond dusted bits.

https://www.amazon.com/10pc-Diamond...363&sr=8-6&keywords=dremel+drill+bits+diamond


----------



## Andre (Jun 28, 2016)

Yup, use carbide tipped drills.


----------



## george wilson (Jun 30, 2016)

I WILL NOT recommend carbide tipped MASONRY BITS for drilling holes in calipers. They make TOO MUCH HEAT. You don't want your jaws warped askew. When they close,there should be NO LIGHT seen between the jaws. And you can see a TEN THOUSANDTH INCH of light through 2 flat steel  surfaces. Get a decent straight flute solid carbide drill. It won't break your bank,and if you don't break it,will be useful to have around. I drilled mine that way years ago to mount calipers on my then mill drill. It worked fine.


----------



## brino (Jun 30, 2016)

Still working on my home-made EDM....not quite there yet.


----------



## bfd (Nov 8, 2016)

hardened steel can have a hole poked in it with a carbide rotary file.


----------



## kingmt01 (Nov 8, 2016)

george wilson said:


> I WILL NOT recommend carbide tipped MASONRY BITS for drilling holes in calipers. They make TOO MUCH HEAT. You don't want your jaws warped askew. When they close,there should be NO LIGHT seen between the jaws. And you can see a TEN THOUSANDTH INCH of light through 2 flat steel  surfaces. Get a decent straight flute solid carbide drill. It won't break your bank,and if you don't break it,will be useful to have around. I drilled mine that way years ago to mount calipers on my then mill drill. It worked fine.


If it's mounted to the machine why would it matter? Your just setting relative 0 anyways.

I was drilling some unknown steel the other day. It was very soft & cutting like butter with long curly chips from my 1/8 drill for 3/16" when it hardened & I couldn't drill past that point even with carbide. I had to use a larger drill to go around it & chip that spot that hardened out. Nice piece of metal. I just have to remember to keep it cool because it air hardens right now.


----------



## Silverbullet (Nov 8, 2016)

Just a thought , see if I raise any commotion. Would a plasma cutter shoot a hole if mounted with a quick jog of the switch? I know the heat but it could be done with a heat sink around the column of the vernier .


----------



## Christian Poulsen (Nov 8, 2016)

Glad to see you gotta' hole in that SS...Next time, like some said above, after center "divet" (don't work hrdn this either!) solid carbide twist drill running straight and no (or as little as possible) runout...cutting fluid (rapid tap or whatever)...rpm not to slow, not to fast (LOL).... peck and cut, peck and cut (make sure you cut because "rub" = heat = work hardens some materials (like some SS bad) = not fun!


----------



## Christian Poulsen (Nov 8, 2016)

brino said:


> Still working on my home-made EDM....not quite there yet.


I can't wait to hear.... 8 "Sparkys" (3 Agie CNC with 3R "Macro" tooling), (5 Eltee "conventional" each with about every type of 3R "Mini" accessory and tooling available including rotary heads and orbiting heads)....and 2 Agie "Wire Sparkys"


----------



## kingmt01 (Nov 8, 2016)

I was thinking they were SS. Might not work well with the electronics but I run water over SS while cutting. If it gets hot it's hard. For big holes try step drills. They always work well for me.


----------



## Subwayrocket (Nov 8, 2016)

I use all M42 bits here with good success . I would imagine carbide would be better , just more expensive and maybe easier to break. 
This small M42 set works well and is pretty cheap https://amzn.com/B007BTPU6W 
On Ebay , the seller Drillhog has good prices on M42 drills , he also has "Or Best Offer" on some ...and he "deals" a bit . 
Good luck with the caliper, post some pics !
~Steve


----------



## george wilson (Nov 8, 2016)

Mounted on a machine,warping the jaws might be o.k..But,what if at some future time you want them back as regular calipers?


----------



## Christian Poulsen (Nov 9, 2016)

Subwayrocket said:


> I use all M42 bits here with good success . I would imagine carbide would be better , just more expensive and maybe easier to break.
> This small M42 set works well and is pretty cheap https://amzn.com/B007BTPU6W
> On Ebay , the seller Drillhog has good prices on M42 drills , he also has "Or Best Offer" on some ...and he "deals" a bit .
> Good luck with the caliper, post some pics !
> ~Steve


I don't have a numbered set (wish I did, they're on my list), lettered, or metric set but I have a fractional set here at home, also very good drills for harder, tougher work!
I'm "all about carbide" though but yes, ya' sure gotta be on top of it all (more so) with carbide drills because easy to "snap, crackle, pop!" (lol)


----------



## Subwayrocket (Nov 9, 2016)

Christian Poulsen said:


> I don't have a numbered set (wish I did, they're on my list), lettered, or metric set but I have a fractional set here at home, also very good drills for harder, tougher work!
> I'm "all about carbide" though but yes, ya' sure gotta be on top of it all (more so) with carbide drills because easy to "snap, crackle, pop!" (lol)


 I'd like to have a set of carbide drills, but they are expensive. I haven't had anything in my mill that the M42 drills wouldn't cut. I got that set a few years back and it was only $19 ...now it's 28 .  Too many people left good reviews ...lol   I think it's a good set for someone starting out in milling . https://amzn.com/B007BTPU6W   
I'll be watching to see how it comes out for the OP . I have the same mill and would like to have a quill DRO too .


----------



## Christian Poulsen (Nov 9, 2016)

Subwayrocket...I thinks somewhere above JE says he goter' done and it's operational (BTW before I sold (like a dummy lol) my Jet table top, I installed a little vernier DRO kit from Amazon:
Note: there's a few for around $50 and under
https://www.amazon.com/s/ref=nb_sb_ss_c_3_8?url=search-alias=tools&field-keywords=mill+dro&sprefix=mill+dro,aps,205&crid=NZXQ3WJ82SQS


----------



## kingmt01 (Nov 9, 2016)

george wilson said:


> Mounted on a machine,warping the jaws might be o.k..But,what if at some future time you want them back as regular calipers?


At my house they are a consumable. I try to take care of them but they get well used. I've had 5 of them I believe which is pretty good considering how much I use them. The get used in the machine shop, welding shop, at the reloading bench, out in the wood working area, & even in the driveway under the hood or under the car. At $10 they are disposable. I used to be even more genteel with them until I learned how nice of a scribe they make.


----------



## george wilson (Nov 10, 2016)

I don't rely on $10.00 calipers . Depends upon the accuracy you expect,of course. Some of them aren't bad,really. I think my Starrett cost $125.00. My first one was a Craftsman,which Sears sold. It lasted several years, was a good caliper, and was dropped a few times on concrete. The 3rd. drop did it in,IIRC!

I had a Mitutoyo that was a good caliper for several years. It finally went bad.


----------



## kingmt01 (Nov 12, 2016)

To each there own but I don't count on calipers when I need accuracy but I'll tell you that I've compared readings from my $9.99 calipers from HF to my micrometers & the reading is within half a thou. My newest pair will read a tenthou. They are very accurate & repeatable. For my use I really don't need any accuracy only repeatability since everything I do is measured in shop & with the same tool.


----------



## bfd (Nov 19, 2016)

one way to get a hole in hardened material is to lap it through. take a small bit of clay (playdoh) and make a small wall around the hole location and fill it with lapping compound. then take a piece of copper tubing and mount it in the drillchuck. using an up and down motion cut the hole with lapping compound. its not fast but works. bill


----------



## kingmt01 (Nov 19, 2016)

bfd said:


> one way to get a hole in hardened material is to lap it through. take a small bit of clay (playdoh) and make a small wall around the hole location and fill it with lapping compound. then take a piece of copper tubing and mount it in the drillchuck. using an up and down motion cut the hole with lapping compound. its not fast but works. bill


Interesting
I've never tried to lap a hole into a piece. Might have been faster then the last time I tried to drill through a hardened piece. I had to drill a chainsaw bar. I went through 4 drills & sharpened those drills more times then I cared to count.


----------

