Need to drill 15/16" holes in steel

[BloomingtonMike]

I need to drill about 24 holes, 15/16" diameter, in 1/8" mild steel for an upcoming project. The largest bit I currently own is 1/2". I'd rather not try to make the step up from 1/2" to 15/16", but I also don't want to buy several large diameter bits I'm not likely to use again. I was wondering if anyone has a recommendation on decent hole saw for steel. I don't expect a regular hole saw would hold up too well, but what do I know? Suggestions?

What's the size of the part/s?

[Cooler]

Start with a pilot hole of maybe 3/16" and make successively larger holes.  Use a good cutting oil and a slow drill speed.  And a drill press is ideal.  Let the drill do the work.  Don't try to force the bit in with lots of pressure.

[Jason28]

Sorry I haven't responded before now; life has gotten in the way.

First let me cover the questions about my drill press. It's a Rikon 30-217, 1.5hp, it's lowest speed is about 200 rpm. It's more than up to the task. Clamps and cutting fluid I have.


The 15/16" comes from the outside diameter of 3/4" metal conduit. But I may end up using iron pipe, so the hole dimension may change. As for the steel itself, after further looking I may be able to use thinner stock than 1/8" - I went with that because it's the easiest for me to find locally.

As for the advice given:
daddo: I appreciate the new source for drill bits.

Roly: It never occurred to me to look for a hole saw size sized for conduit, but it makes sense they'd exist, right?

museumguy: I have no idea why I didn't think of a step-drill. I've got several already, though not in that size. I think.

BloomingtonMike: I haven't actually settled on that yet. Life has gotten in the way so I've had to shelve the project for the time being. That and further looking has given me some other options, so I think I may be doing a few tests to see what I'm going to do.

The pieces will end up in a variety of uses: guides, reinforcement and possibly clutch plates. It all depends on which way I decide to go. The advice here has lead me to options I hadn't considered so some playing around is in order. Thanks to everyone!

[Phil Thien]

The only thing I'll add is...

I have quite a few hole saws in both bimetal and carbide.  I feel the bimetal will cut substantially faster than the carbide in this instance, as the kerf is much narrower and the teeth start quite a bit sharper.  If you go slow (RPM) and use some cutting fluid, I think the bimetal will outperform the carbide.

[Roly]

The hole size for electrical conduit is for the fitting, not the od of the pipe.  For 1/2" conduit the knock out is 0.885" and for 3/4" it is 1.115",   15/16" is 0.9375.    With a step bit you may have to drill from both sides if the step height is less than your 1/8" steel.     Roly

[brofessor]

For 1/2" conduit use 7/8 hole saw, for 3/4 conduit use 1 1/8 , and 1" uses 1 3/8 hole saw. Thats the standard sizes. I use hole saws on a daily basis. If you want longevity pick up a carbide one. I like a step drill for thinner metal but it can sometimes be slow on thicker metal. Or you can pick up a small knockout set if you need a cleaner hole. An electrical supply house may have a better selection of hole saws than the local big box store but that can definitely vary. Best of luck

[kurt18947]

Depending on how fussy and how big a hurry you're in, some of the annular cutters on Amazon aren't terribly expensive. I'd never heard of such a thing but it's now in my fund of general knowledge. My very limited experience with hole saws is that they're not fast though they might be the least expensive and they'd remove the least material.

[alanealane]

I need to drill about 24 holes, 15/16" diameter, in 1/8" mild steel for an upcoming project. The largest bit I currently own is 1/2". I'd rather not try to make the step up from 1/2" to 15/16", but I also don't want to buy several large diameter bits I'm not likely to use again. I was wondering if anyone has a recommendation on decent hole saw for steel. I don't expect a regular hole saw would hold up too well, but what do I know? Suggestions?

Lots of options here! Silver Deming drill bit will work if you can drill incrementally larger sizes up to the final diameter. Hole saw with oil will work with patience. Step drill may work ok but I'm not sure it will get through 1/8" before the next step diameter starts removing material. 
A more pricey but very nice option is called a Rotabroach. It's a fancy hole saw specially designed for metal. All it requires is a small pilot hole for a spring loaded pin to locate the cutter on. 
http://shop.blairequipment.com/mobile/Pr...Code=13218
http://shop.blairequipment.com/mobile/Pr...Code=11344

[Arlin Eastman]

Here you go for bits I get for wood but are made for steel and fit right in your drill press or lathe.

https://www.wttool.com/index/page/catego..._params%3D

[Timberwolf]

I need to drill about 24 holes, 15/16" diameter, in 1/8" mild steel for an upcoming project. The largest bit I currently own is 1/2". I'd rather not try to make the step up from 1/2" to 15/16", but I also don't want to buy several large diameter bits I'm not likely to use again. I was wondering if anyone has a recommendation on decent hole saw for steel. I don't expect a regular hole saw would hold up too well, but what do I know? Suggestions?

.......................
I would use a "bottom cutting" four flute end mill....check ebay for availability...That size is not uncommon, but the challenge would be to hold it..the chuck on your DP is probably not the answer. You "might" be able to find one with a 1/2" shank.