Thread: Which drill bits these days? Things seem to have changed. Still Dormer?

Originally Posted by FenceFurniture

I think you mean more bonkers, but thanks for being polite.

If I were to use them (wire gauge), they'd be straight out of that box, and into a metric labelled wooden rack, in ascending metric size order with all the other bits (people don't understand why I currently have my drills in a rack ordered like this:
2.5 – 2.78 – 3 – 3.18 – 3.5 – 3.57 – 3.97 – 4 etc
Uhh, maybe so I can pick up the next biggest size if that one wasn't big enough?
Imperials are also sub-labelled with their fractional fit. Dead simple, dead easy to use.

In fact, right now I'm compiling an Excel list of wire gauges, Letter sizes, fractional Imperial, and metric up to 25mm (sorted into increasing metric) to see if those wire gauges and letter sets are are worthwhile. Just a matter of finding the best set fit for me. However, I wouldn't mind if they deleted gauges 60-41....having 20 bits covering 1.02 to 2.44mm is just a little bit silly.

Don't forget that there are "American wire gauge" and "British wire gauge" also one or two odd ones that pop up from time to time. I have two, one of each "AWG" and "BWG"

Originally Posted by FenceFurniture

That a crook link crocy, but I got there.What have you been drilling with them?

I accidentally won about a tonne of HT steel in an auction, so just about everything I make now is out of 4140 or 316SS. I found the flutes on the P&N drills were wearing, so about 2 years ago I bought the set from Mag-Pro, haven't been disappointed so far.Rgds,Crocy.

I have a mostly complete set of Dormer number drills and have been giving thought to buying a .01 metric set of some description and getting rid of the Dormer set but then I am not a machinist so why would I need a set @ .01 steps when I hardly use the Dormers I have. I bought the set about 30 years ago at a stupid cheap price so they owe me nothing now but a full .01 set would be nice to look at until one breaks and you have to buy replacements 10 at a time. The problem with small drills is you need an accurate DP to use them.

I went through all that analysis in the last few days Chris – Wire Gauge, Letter Gauge, 0.1 steps. None of the Wire or Letters were of any benefit, and for me there are only about 8 of the 60 (1-6.0mm) 0.1mm steps that are useful, so that they fill in ~0.25 steps in the metrics in combination with some Imperials. I'm pretty settled on a metric set of Guhring M35, an Imperial set of Guhring TiN tipped HSS Imperials (even though I don't really need any of the ones above 3/8), and about 8mm 0.1 steps. A handful of Long series, and even less Extra long will round it out to be a pretty complete set for me.

Originally Posted by FenceFurniture

....having 20 bits covering 1.02 to 2.44mm is just a little bit silly.

For a DIYer yes, but mot if you are are making small precision machinery. In 2004 when I visited Washington DC I met an interesting bloke who worked in a satellite factory as a technician - he operated small and mini CNCs to make small and micro mechanical parts for the aerospace and aeronautics industries. His main task was driving a couple of CNCs. loading up blanks, cleaning up swarf, and changing out the broken/damaged bits, and then as he called it pressing "go". He had a side hustle making unusual Ti jewellery from scraps. I asked him if I could visit his workplace but I would have needed to get FBI clearance and didn't have time for this so I didn't go.

In 1990 I was living in in San Diego and did managed to visit a specialist factory that made made all sorts of gear (mainly mini compressors) for the aerospace industry including the cooling systems for the electronics for guided weapons systems. I also needed a security clearance for this visit and because I was living there I had time to get it - it took about a month to get it. Had to wear cleanroom booties, Tyvek overalls and head covering, I spent the whole day there, rows and rows of shiny CNCs and machinery rooms in gleaming white clean rooms. You could have eaten off the floor.

Just a query on rust resistance: I've previously noted that HSS is far more resistant to rust than other various tool steels, but does the inclusion of 5% Cobalt increase that resistance or have no effect?

At the same time I have noted that not all HSS is equal in this regard: Colt HSS M2 Brad Point bits are somewhat more resistant than Suttons Vipers (also European HSS M2 steel), which are much more resistant than the Frost Imperials (Chinese HSS). I was given a very bitter lesson about wood tannins and rust a few years back: I made a bit rack out of She Oak (Allocasuarina sp) and after a some months I went to get out a bit that I hadn't used yet. Bloody thing was rusted in and wouldn't budge without a vice and pliers! OTOH the forstner bit rack was made from Huon Pine and they were fine, even though they are just high carbon steel not HSS. When I went along the twist bits rack (also She Oak) I could pretty easily get out all the Viper Metrics, but almost all of the Frost Imperials were rusted in.

Originally Posted by FenceFurniture

Just a query on rust resistance: I've previously noted that HSS is far more resistant to rust than other various tool steels, but does the inclusion of 5% Cobalt increase that resistance or have no effect?

At the same time I have noted that not all HSS is equal in this regard: Colt HSS M2 Brad Point bits are somewhat more resistant than Suttons Vipers (also European HSS M2 steel), which are much more resistant than the Frost Imperials (Chinese HSS). I was given a very bitter lesson about wood tannins and rust a few years back: I made a bit rack out of She Oak (Allocasuarina sp) and after a some months I went to get out a bit that I hadn't used yet. Bloody thing was rusted in and wouldn't budge without a vice and pliers! OTOH the forstner bit rack was made from Huon Pine and they were fine, even though they are just high carbon steel not HSS. When I went along the twist bits rack (also She Oak) I could pretty easily get out all the Viper Metrics, but almost all of the Frost Imperials were rusted in.

Tannins should not produce rust. If it was red rust (a mixture of iron oxides and hydroxides and water) then it was due to water/air absorption. Tannins produce ferrous and ferric tannate are black in colour and rust resistant.

Well, maybe it wasn't the tannins, and must have been something else in the She Oak, but it was a shocker. As I recall the rust was a much darker colour - not the typical red bloom.

If rust is of concern buy some desiccant packets and put them in the index. I have a couple of tools I don’t use often that I don’t want rusty so I keep them in large zip lock bags with a couple of desiccant packets. Works well, the desiccant can be dried in an oven if required.

Originally Posted by racingtadpole

If rust is of concern buy some desiccant packets and put them in the index.

Yes, I had done that, and that's how I knew it was something in the She Oak. The other giveaway was that there was only rust where the drills had been in contact with the timber.

I have hundreds of them scattered throughout my tool drawers.

Bit Stand.JPG

Originally Posted by FenceFurniture

Just a query on rust resistance: I've previously noted that HSS is far more resistant to rust than other various tool steels

I have noticed the same thing. Mainly with old lathe cutting tools. Some of the HSS blanks are 50 years old, not stored in oil, and are still shiny.

I am not a metallurgist, bit I think the amount of Chromium in the HSS provides the rust resistance.

If you believe the specs (e.g.https://en.wikipedia.org/wiki/High-speed_steel ),
all HSS varieties have around 4% Chromium?

Originally Posted by FenceFurniture

Yes, I had done that, and that's how I knew it was something in the She Oak.

Interesting.


1) I really like She-oak. Have some sheets of ply made from it, from old 1900s/1920s furniture. I think at the time it was a cheap and plentiful timber from Queensland?


2) Some other timbers seem to do the same thing. I think this is Mahogany (or an Australian equivalent):
IMG_2386.jpg
Timber was well oiled, or maybe WD40'd, before the countersinks went in there

Hi Guys,

Whilst some steels seem to rust easily I have a notion that the amount of water in the wood is the major cause of rusting of round items supported in them. Some woods contain more water than others !

Originally Posted by nigelpearson

Interesting.


1) I really like She-oak. Have some sheets of ply made from it, from old 1900s/1920s furniture. I think at the time it was a cheap and plentiful timber from Queensland?


2) Some other timbers seem to do the same thing. I think this is Mahogany (or an Australian equivalent):
IMG_2386.jpg
Timber was well oiled, or maybe WD40'd, before the countersinks went in there

Yeah that's nice and red eh? There are certain timbers that are really bad for this. IanW over on t'other forum knows a fair bit about this (and wised me up to the She Oak problem).

When you say the Mahogany was well oiled, do you mean just the outside before you drilled the holes, or in the holes as well?

In preparation for the arrival of drill bits early next week, I'm planning out a new block which I'll make from Huon Pine. My idea at this point is to oil the timber surface before I drill any holes, then drill the holes, put machine oil in the holes (because it doesn't polymerise) leave it to soak in for perhaps 24 hours, drain out the excess, and put the drills in around 24 hours later (the stub end will be in the hole, so any oil can be easily wiped off). I might even use G15 instead of machine oil.

For the old drills which are to become my travellers, I'll do the same thing, but I'll get a clear acrylic open box made to sleeve over it, and hot glue a couple of silica gel sachets in the top of it.

How's that for a plan? Any flaws to be seen?

Here is a link to the thread (from post #8) where IanW is talking about some different timbers being bad news for steel. He does talk about tannins being a problem there.

I just now took a pic of three of the old drill bits that have been sitting in that remaining She Oak drill stand. They all reside in this order in the stand. On the left is a Chinese Frost, and the other two are NZ made Suttons. All "HSS" but I suspect one of them has significantly less chrome, tungsten and other goodies.

IMG_20220722_183428_1.jpg

I had a couple of years of shed inactivity, which included the persisting it down rains for six months Nov 21-April 22. There is not a very great deal of rust on other tools hanging on the walls. Some on the planes, but not like this.