Small drill bits, <<1mm

[Martin WhittleParticipant @martinwhittle67411]

Where would you buy small drill bits, say in the range 0.4 to 0.8mm?

I tried to drill a small brass piece the other day on the lathe with a 0.6mm bit . After an initial location peck with a centre drill, I found the small bit was not at all interested in drilling, but just started to physically spring into an arc with increased tailstock pressure.

The bit was from a set I bought from China via eBay, a few years back, 10 off many sizes from 0.4mm to 3mm or so. On examining the bits with an eyeglass, I was shocked at the tip grinding: I did not expect it to be necessarily that perfect and symmetrical at the price, but the smaller sizes often had a remarkably rounded and amorphous tip, or a very asymmetric one. Or even no sign of a central point! Larger sizes appeared very much better, but I have not actually tried them as I have other drills for above 1mm.

So on to a ‘Microdrill’ set bought at a show. This was better, but nothing to write home about. I than found that I had a few higher quality drill bits stored away in a bag, and one of these worked as perfectly as expected.

Therefore I would like to obtain a set of bits of the size suggested above. Prices seem to have a very wide spread. E.g.

• UK Drills do 10 off individual sizes for prices under £1.30. I have used UK Drills previously and been very pleased, but have not tried them for small sizes.
• Arceurotrade do ‘polished drill bit sets’, 20 piece set, 2 off sizes 0.3 to 1.3mm for £3.47. Sounds absolutely perfect, but how good are they? I have a couple of 1.3mm cobalt HSS bits I purchased from them a few years back, examination shows they look good apart from having the tip a bit off centre, maybe only 0.1mm, but that is a very significant amount on a small drill, and I want significantly smaller sizes.
• Cousins appear very trustworthy and clear: they stock a number of classes of drill bits. They recommend that for metal, use bits from Dormer. No problem with this, although the price is obviously higher for a quality item, generally north of £3 each, rising to £6.75 for a 0.2mm bit (now where did I drop that little bit on the littered workshop floor?). Their other ranges are said to be suitable for soft materials such as ‘wood, wax, and leather'. Fair enough, and also describes the bits I have, fully capable of battering their way through a sheet of balsa.
• Cousins also carry 2 manufacturers versions of ‘jewellery drill bits’, small bit diameter on 2.35mm shank, relevant prices either around £1 or £3.

So I would like to buy a set with more than 1 of each size to allow for the odd breakage. I have probably psyched myself up to paying around £3 per bit for a quality item (either Dormer or A*F parts from Cousins), but would be interested in other’s experience.

Re. the ‘jewellery bits’, these obviously can be used in chucks of greater minimum capacity, have others found them good?

Martin

[Martin WhittleParticipant @martinwhittle67411]

[pgk pgkParticipant @pgkpgk17461]

I've bought stuff from UKdrills and been pleased wth their service. They once sent me dies instead of taps and when i rang up they aplogised, sent the taps and told me to keep the dies. I haven't used their tiny drill bits (under 1mm) but I've been very pleased with the price and performance of their cobalt drills for general use and in the smaller sizes I'm not going to bother trying to re-sharpen them.

pgk

[Stuart Smith 5Participant @stuartsmith5]

I have bought small drill bits from CPC, mostly for making PCBs. I have just done a search for drills up to 1 mm on their website and these are the results:

**LINK**

Stuart

Edited By Stuart Smith 5 on 05/07/2020 23:05:23

[HopperParticipant @hopper]

Ive been very pleased with small drill bits from Tracy Tools.

[Simon CollierParticipant @simoncollier74340]

I recently bought a set of 61-80 Sutton drills on EBay. About 80$, but several places had them at $120. Cheap small drills are rubbish. I too looked at some under magnification and some were just rounded blobs that could not possibly cut. I've been making injectors and you need sharp, accurate drills.

[PeroParticipant @pero]

I have a range of small carbide drill bits ranging from 0.1 to 3.0 mm. These are mostly ex China and principally advertised as PCB drills. The sharpening on these is generally good, i.e. accurate ( visually at least ) but quality ranges from good to bad with frequently chipped cutting edges. Usually you will get a few good ones in a set of ten, which at the price is probably reasonable. Unfortunately I am yet to find a seller who will supply consistently good ones, even at a somewhat higher price.

Given that the drills themselves seem to be of reasonable quality – does anyone have method of accurately sharpening them? I note that this probably also means being able to see them, especially in the very smallest sizes.

Pero

[JasonBModerator @jasonb]

If you do want a set then the Dormer drills are available in the same type boxes as the "microdrill" sets of 20 bits for about £45 or less if you shop around

Personally I've not had problems with the Microdrill sets bought from shows and have happily drilled down to 0.3mm in brass and 0.5mm in steel with them. Unless you have a high speed spindle they are never going to drill quickly as the cutting speed will be low.

[pgk pgkParticipant @pgkpgk17461]

I'd guess that at a hobby level finding a realistically priced sharpening system might mean making one.

At oen point in my career I got involved with in-house histology and while it was possible to buy older style microtomes for cutting the sections it was only going to work with correctly sharpened and honed blades. My old university agreed to resharpen them for me and i was gob-smacked at the quality of edge one can get when checked with decent magnification microscopy after using machines that honed against glass plates flooded with honing slurry.

Even just indexing a tiny drill bit in a holder and getting the system rigid enough for manual honing with fine japanese wet stones also indexed would be a challenge but perhaps a USB microscope (cheap enough) might be a good place to start – or buy multiple cheap drills and check their edges and throw away the duds unless into production work where time is a geater issue than cost?

pgk

[Former MemberParticipant @formermember32069]

[This posting has been removed]

[Andy CarlsonParticipant @andycarlson18141]

I do small scale stuff so use a lot of sub 1mm drills. My experience has been pretty hit and miss. I tend towards buying 10 packs of the very small sizes but mostly these purchases have been opportunist and therefore not very repeatable, perhaps from vendors selling bankrupt stock.

On the positive side, I have an excellent pack of 0.4mm Guhring drills (eBay). My Expo 0.5mm HSS drills (easily available) have been good. A pack of 10 0.31mm Titex drills (on 1mm shanks) has also been excellent.

On the negative side I've bought 10 Heller German made 0.3mm drills which have been utterly hopeless and the Titex 0.45mm drills bought on the same occasion as the others from the same manufacturer have not cut at all well.

Mostly I use the drills by hand in a pin vice for drilling thin brass and nickel silver but more recently I've used the 1mm shanked ones in my Proxxon MF70 and some in the lathe (with the drill in a pin vice held by hand but using the tailstock chuck to loosely guide the back end).

[jimmy bParticipant @jimmyb]

I buy carbide drills from China, via ebay, sizes .1mm to 2mm.

Never had any issues.

Jim

[BazParticipant @baz89810]

+1 for Drill service Horley, excellent quality, I have used them for many years and never been disappointed with quality or delivery.

[Chris Evans 6Participant @chrisevans6]

Another plus for Drill Services Horley

[Stewart HartParticipant @stewarthart90345]

Use to do a lot of small hole drilling at work we always used Titex drill from Germany there expensive but are very good. some followed me home. I've tried the cheep Chinese stuff and they are rubbish some of the sets you can buy at shows are not too bad, some one in China must make good small drills with the stuff that they make I guess they keep them for them selves.

Small drill really need high speeds to work really well so why not make a high speed drilling attachment like this one I made

Stew

[egaParticipant @ega]

Stewart Hart:

I enjoyed the video.

In the lathe I had expected you to rotate the work against the drill. My understanding is that doing so is helpful in maintaining concentricity as well as increasing the effective speed of the drill.

[HollowpointParticipant @hollowpoint]

I find small drills need to be good quality. Because they are so fragile they need to be sharp.

Personally I would shop around on ebay for new old stock. Top brands like dormer, presto, guhring, osborn, cleveland etc.

[KWILParticipant @kwil]

I noticed that the drill was bending in both instances so I guess the tailstock is not set square to chuck axis?

[pgk pgkParticipant @pgkpgk17461]

Some speculation here from me…
A quick lookup suggests that 0.1mm drill into carbon steel ideal is 32,000RPM.

It's possible to buy cheapish dental electric micromotors at 22-27,000RPM or low speed air-driven handpieces at around 40,000rpm. High speed dental handpieces run at 200-800,000RPM but most of those are contra-angle and making a holder would be dificult. The low speed ones are available straight – indeed they are a base with output shaft going into the handle/bur holder so could be adapted directly to a collet system and drill bit or the drill bits would need adapting to the handpiece latch system. benefits could include a coolant option. There'd be some pfaffing about coupling the compressor to dental handpiece line and fiing up a pressure bottle for the coolant.

Additional benefit might be starting the hole with a pilot bur.

pgk

[CirclipParticipant @circlip]

Not beyond the range of possibilities to use the 4 facet drill sharpening jig with glass plate and diamond slurry.

Regards Ian.

[Rod RenshawParticipant @rodrenshaw28584]

it's possible to make small drills using methods used by watchmakers. "Swiss" or pivot drills can be made using a simple jig to put a point on what is effectively a "D" bit. Raw material can be hardened silver steel or "musical" strings intended for banjos, which are already hard. See articles by D G Gordon in ME 2 .1.1975, ME 16.1.75 and ME 15.2.1980. They don't need high speeds but do need backing out and clearing frequently. Gordon describes sizes down to about 10 thou and if you can make it once, you can sharpen it again when needed. Not much use for those needing a lot of holes but for the odd few for injectors etc.

Rod

[bernard towersParticipant @bernardtowers37738]

Unfortunately the spade tip of even a small center drill is larger than the intended drill which can allow the drill to wander. If you have a piece of 1/8 carbide or hss grind 3 or 4 facets giving a approx angle of 60deg and a sharp point, make a small divot which will be the lead in for the drill. The idea came from a cnc website and they were charging over £40 for just one of these!!

[BazParticipant @baz89810]

Bernard, centre drills are available down to .3 diameter, I would think that is small enough for most work.

[bernard towersParticipant @bernardtowers37738]

The only problem with a .3 centre drill is that the .3 tip is very short and fragile why have the problem when there is a solution that’s cheap to make and almost impossible to break,

[Rod RenshawParticipant @rodrenshaw28584]

Spotting drills are available in small sizes and have much more robust points than centre drills. They are made for the job of "starting" drills and have better geometry for the purpose than centre drills; which are really made for drilling centres for turning work "between centres". Use of centre drills for starting twist drills is traditional amongst model engineers but they are not ideal for this purpose.

Rod

[Author]

Posts