Proxxon bench drill TBM-220

[rob77]

there is an extremely simple and elegant solution see attached pic.

Not a bad idea, although it will probably get annoying if you are removing the spindle often. Maybe a wingnut would be better? Have to test it on mine.

you would need a screw with wings for that .. it's easier to put a M6 socket head screw there and have a Hex/Allen key handy .. btw you need the Allen key anyway to release the tilt locking screw.

[StanleyAdams]

If your HSS bits break, that only means that either you aren't drilling straight, you are using too low RPM or the stand is vibrating too much, putting too much lateral strain on the bit. For PCB drilling carbide is better, but only because it won't dull as fast as HSS. I am using regular HSS bits in my Proxxon stand and never had one break so far.

I'm neither using too slow RPM, I use it at almost the fastest setting, if not the fastest. Nor am I putting too much lateral force, otherwise the hard metal drills would break as well. They brake when I ever so slightly jerk the PCB when the drill has not yet left the hole, and it happens from time to time. Now, maybe it's the quality of the HSS ones I've used, but even finding reputable brand 0.8 ones is hard. I've been using the same hard metal bit for years. Bought two of each size I use. And haven't broken one ever. No problem. No reason to even consider a HSS one for pcb drilling again.

[mazurov]

I have a unit which looks very similar, model TBM-115, likely the same tool made for US line power. This is an excellent drill, solid German design (and mine is made in Luxemburg) , very popular among jewelers .  TIR of the spindle is better than anything I have seen in this price range, i't won't break 0.1mm carbide bit and can likely be used with smaller bits as well but I haven't tried. It is also tiny and sits under the bench until I need it - the main reason I bought it since I keep my bench Jim Williams style' and anything of value must be kept out of it lest it will be lost forever.

It is good for precision work only - PCB, #0-2 taps and such. You can drill up to 3mm in aluminum, but only as a last resort. It will do it but you have to be patient.

[IanB]

I have a unit which looks very similar, model TBM-115...

I can't help observing that TBM is a common abbreviation for Tunnel Boring Machine. But it would seem that the TBM-115 can't quite make holes this big:   

[GK]

If your HSS bits break, that only means that either you aren't drilling straight, you are using too low RPM or the stand is vibrating too much, putting too much lateral strain on the bit. For PCB drilling carbide is better, but only because it won't dull as fast as HSS. I am using regular HSS bits in my Proxxon stand and never had one break so far.

I'm neither using too slow RPM, I use it at almost the fastest setting, if not the fastest. Nor am I putting too much lateral force, otherwise the hard metal drills would break as well. They brake when I ever so slightly jerk the PCB when the drill has not yet left the hole, and it happens from time to time. Now, maybe it's the quality of the HSS ones I've used, but even finding reputable brand 0.8 ones is hard. I've been using the same hard metal bit for years. Bought two of each size I use. And haven't broken one ever. No problem. No reason to even consider a HSS one for pcb drilling again.

You must be using poor quality HSS bits. I've had this problem myself and so have others:

https://www.eevblog.com/forum/chat/now-i-have-a-reason-to-hate-jaycar-even-more/msg283150/#msg283150

In comparison to a decent quality HSS bit, however, it is in fact the carbide bits that are the ones that are easy to break with a little lateral force. I now only buy quality HSS bits from RUKO. For normal PCB drilling operations these are next to impossible to snap and are my preference for drilling phenolic PCB. I hate it when I snap a ~$5 carbide bit. So far I've drilled these three boards with a single RUKO HSS bit and it is still as sharp as when I started:



I only use the fragile carbide bits for fiberglass board, as the HSS bits don't last.

[madires]

I'm quite happy with the Bungard drill bits und I drill mostly FR4 with my 50/E. The drill bits I commonly use are 0.6/0.8 for standard throughhole components and 0.9/1.0/1.1/1.2/1.3 for connectors, large caps, power semiconductors and so on.

[nukie]

Get the MB140 stand with the rotary tool. It's much more versatile and can do a lot more than a fixed drill press. You don't need lots of pressure drilling PCB and a detachable rotary tool saves you space.

I am very happy with my setup.

[janoc]

Re bad bits:

I didn't believe it when my dad has shown me these "HSS" bits from a local supermarket after a bit of light use:


Yeah, those bits are actually bent. You can get even such "quality" 

[Monkeh]

Can't say I've ever bent a bit. I've bent the drive shaft on a supermarket drill, though. Visible runout on the chuck itself is a sight to behold.

[janoc]

Can't say I've ever bent a bit. I've bent the drive shaft on a supermarket drill, though. Visible runout on the chuck itself is a sight to behold.

If you manage to bend a bit it means the steel wasn't hardened at all, i.e. the you have a soft piece of wire and not a drill bit. Basically a piece of shit not fit for the intended purpose. Hardened steel wouldn't bend but would snap instead.

I guess your stores aren't buying the worst and cheapest Chinese-made junk and trying to sell it as high-quality product where you live. The ones in Slovakia do, unfortunately, because people look only at the price.

[rob77]

yeah, the cheap drill bits bend when drilling to tough materials - those are only good for drilling into soft plastic materials

for real work it's better (and at the end of the day cheaper) to buy more expensive quality drill bits.

[Refrigerator]

Man, those bits must be really bad if they break so easily. Here, where i live you can get a set of carbide bits for a couple of bucks.
A pair of 0,8mm carbide bits will only cost you one dollar and those aren't any cheapo bits, they're great bits, really sharp and can stand alot of twisting and bending, they just spring back like nothing happened.
How's prices in your local hardware shops ?

[Monkeh]

Man, those bits must be really bad if they break so easily. Here, where i live you can get a set of carbide bits for a couple of bucks.
A pair of 0,8mm carbide bits will only cost you one dollar and those aren't any cheapo bits, they're great bits, really sharp and can stand alot of twisting and bending, they just spring back like nothing happened.
How's prices in your local hardware shops ?

... Tungsten carbide is very, very stiff. It does not spring. It snaps.

[IanB]

The carbide is only on the cutting edges at the tip of the drill. The drill itself is still made of steel.

[Monkeh]

The carbide is only on the cutting edges at the tip of the drill. The drill itself is still made of steel.

Carbide drills tend to be solid carbide.

The exception is impact tooling.

[Refrigerator]

Man, those bits must be really bad if they break so easily. Here, where i live you can get a set of carbide bits for a couple of bucks.
A pair of 0,8mm carbide bits will only cost you one dollar and those aren't any cheapo bits, they're great bits, really sharp and can stand alot of twisting and bending, they just spring back like nothing happened.
How's prices in your local hardware shops ?

... Tungsten carbide is very, very stiff. It does not spring. It snaps.

Hmm, really? Those little buggers seem to drill through anything...( except concrete )

[Monkeh]

A normal steel bit will drill through anything softer than itself.

This includes fibreglass, normal steels, aluminium, copper, brass, and cheese.

Try and put a hole into a 12.9 or so bolt head with one. If it's steel it'll fail horribly, if it's carbide, it'll go through. Either way it's going to get really, really hot.

E: Oh, and don't buy '12.9' bolts from the same place you buy those drills, eh?

[senso]

Don't do it, it will be a painful experience, after having to cut a lot of 12.9 M14 an M16 bolts all I can say is that they chew through cutting disks that is not even funny, drilling them, only in a milling machine with some horses in the spindle I would say.

[robrenz]

A normal steel bit will drill through anything softer than itself.

This includes fibreglass, normal steels, aluminium, copper, brass, and cheese.

Try and put a hole into a 12.9 or so bolt head with one. If it's steel it'll fail horribly, if it's carbide, it'll go through. Either way it's going to get really, really hot.

E: Oh, and don't buy '12.9' bolts from the same place you buy those drills, eh?

I just made 5 small grinding quills for a customer and I used 12.9 socket head cap screw shanks (170,000 psi yield) for the material. I used high cobalt steel drills to drill a .024" diameter hole .531" long thru the center for coolant flow. Not easy but very doable.

[Monkeh]

A normal steel bit will drill through anything softer than itself.

This includes fibreglass, normal steels, aluminium, copper, brass, and cheese.

Try and put a hole into a 12.9 or so bolt head with one. If it's steel it'll fail horribly, if it's carbide, it'll go through. Either way it's going to get really, really hot.

E: Oh, and don't buy '12.9' bolts from the same place you buy those drills, eh?

I just made 5 small grinding quills for a customer and I used 12.9 socket head cap screw shanks (170,000 psi yield) for the material. I used high cobalt steel drills to drill a .024" diameter hole .531" long thru the center for coolant flow. Not easy but very doable.

I should note I define 'normal' as HSS, or even carbon for DIYers. Cobalt steel is a rather tougher beast.

If you can pull that off with an HSS bit, I'll chew on my hat a bit.

[SeanB]

If I drill 316 stainless steel I budget one HSS drill bit per hole. Cobalt steel 1 bit per hundred holes. Over 5 holes the cobalt steel is cheaper. One nasty job it was 5 cobalt steel bits per hole, as the Bastid who made this particular plate had work hardened it so much, so the bits would catch on a hard spot and shatter. thankfully did not break the M5 tap on cutting the new thread into it. The original thread was 5 turns in and poorly formed. I went all the way through.

At least it was not the other machine with some really tough incalloy. Basically laughs at any drill bit or file, you use grinding or carbide bits on it only. Carbide taps are expensive. That has a wear plate that is hardened to 65 Rockwell C on it. It wears the other side though.

[Fred27]

Getting back to the TBM-220 itself - another recommendation from a happy purchaser.

I haven't used it for the intendeddrilling PCBs yet as I'm in the process of building my new workshop. As a result of this I've been using it to drill 4mm holes in 3mm think mild steel and 2mm think stainless angle iron. The little drill coped very well, although can be stalled. The chuck is fine. However the included chuck key is a load of rubbish. A small complaint though.