Drilling brass castings

[Hauk]

I need to drill a lot of small holes (0,3mm/0,4mm) in some brass castings. The brass in the castings seem to be quite hard, and I am breaking drill bits at an alarming rate.

Does anoyone have advice? On such small drill bits it seems impossible (at least to me) to make adjustments to the drills in any way.

I am using an drill press with max 9500 RPM. Could I expect better results with a higher speed?

How about cutting fluids?

Any input is much appreciated!

Best regards,
Hauk

 

[goldstar31]

Depends on a lot of variables. If the casting is not flat where the drill goes in, you will snap a thin drill. You need a tiny end or slot drill to get avoid wandering---- and snapping. Again, I would follow with a centre drill or a Slocombe drill to start things. Then I would clear chips that will clog a drill.As for cutting fluids, I think that they are less important than the foregoing advice. Me, I use purified lard oil-- but I'm old fashioned.What you should realise is that chips jamming is the worst case scenario. If you don't believe me, knock up a baby D bit and play with a bit of scrap brass..Bang, crash and wallop.CheersNorman

 

[Swifty]

With drills that size, lots of pecking is required. As Norman has said, swarf can be your biggest problem.

Paul.

 

[ICEpeter]

If you are using a drill press and its quill is operated by its handle, you may ought to supplement it by using a micro drill attachment that allows sensitive drilling, using finger pressure, instead of the quill handle with somewhat uncontrolled pressure leading to breakage of those very tiny drills.

Peter J.

 

[ICEpeter]

Micro Drill Adapter picture


Peter J.

View attachment Micro drill adapter.doc

 

[Toolguy]

I would try solid carbide drills with 2 straight flutes if they come that small. I have them down to 1/16, I don't know how small they go to. Also check out www.harverytool.com for small carbide milling and drilling cutters. They are super quality with moderate prices.
You don't say how deep the holes are, for shallow depths a carbide spade drill may be the way to go.

 

[goldstar31]

Perhaps you should Google www.danielslondon.com. It is something to read- when you have read the rest!norman

 

[jennyxie]

I agree with Norman and others in this discussion to a large extent. And I'd like to add a point - temperature. you may control it strictly to ensure a good result. Because I don't know what kind of drill you are about to use, I can't offer you exact suggestions on temperature controller. you are welcome to write back. Jenny.

 

[Wizard69]

The type of brass can be a big factor here, especially if it is a bronze like alloy. One time in my youth I had to drill holes in some way material made out ampco 18 brass I believe. (This was a long time ago). That stuff was damn near impossible to run a drill bit through. I should have known better as the engineer that wanted the holes in the material smirked when I said no problem.

The point is knowing the alloy might help you find the right solution. Also take note of the people above talking about starting the drill bit. It is advisable to spot the hole locations before drilling. You simply can't afford drill wander when starting the hole.

 

[cynthiamyra]

For drilling hard materials one of the suitable methods is deep hole drilling. You can use gun drill for making straight, sharp and accurate holes in to any hard material.

Deep hole drilling is beneficial across several applications. This process can be used in aerospace equipment, engines, armaments, Gas and oil exploration equipment, and is commonly used in machining processes.

Contact here http://top-seiko.com/gallery/deep-hole-drilling/ for your deep hole drilling needs.

 

[Blogwitch]

I am lucky in that I have a precision drilling machine, it only goes up to 10K RPM, and I have drilled many 0.01mm (0.0004") holes with no problems at all.

This is one I started to make that was to get me up in the 80K to 90K speed range, but never finished it as I found my larger drilling machine (above) would cope very easily with small carbide drills as it had such a rigid spindle.

In theory, this size of drill requires around 90+K rpm, but I normally drill at around 4K to 5K and I have broken very few of the tungsten drills. I buy resharpened ones off ebay, and if taken steady, will require no previous centring on all materials. The middle one, sold as PCB board drills.

I have very fine feed on my machine, and I think that is your main problem, you are trying to force the drill down into the hole without actually 'feeling' your way through.

As previously suggested, get one of these that allow very fine feeding indeed as you have a lot of 'feel' with them, which your main feed won't have.

http://www.arceurotrade.co.uk/Catal...k-Arbors/Micro-Drill-Adaptor---JT0---12-Shank

Hope this helps


John

 

[ICEpeter]

John,
This is an old post that came back to life for some unknown reason.

Peter J.

 

[Blogwitch]

Thanks Peter,

I don't think it really matters as someone might need the info I provided or it might give someone who hasn't seen such things a bit of inspiration to have a go themselves.

BTW, the very high speed one could be made for very little money if you have a few big bits in the scrap bin, I was given 3 of the comparitor stands that I used and the air grinder and chuck came to about 30 UK pounds if you don't mind shopping around.
On the larger one I invested in a mag chuck so that steel fixtures could be used, and when set up correctly and the mag chuck energised, hundreds or even thousands of parts can be drilled at the same settings. I used it mainly for drilling gas jets.

Thanks again

John

 

[Engineeringtech]

The old timer suggestion for cutting brass and copper was to use bacon grease or milk. Yes, I said MILK on the softer stuff. I have never had the chance to verify how well it works, because I don't come in contact with much brass. Your hole sizes are pretty small. Any depth over 5 to 7 x the diameter would be considered a "deep" hole, and likely to bind up. So yes, a peck cycle would be very important. Not a fun job.

 

[gus]

With drills that size, lots of pecking is required. As Norman has said, swarf can be your biggest problem.

Paul.

Well said and from good experience drilling those pesky micro size orifices on our engine carbs. W/o the micro pecking drill chucks and very frequent pecking to clear chips,we would have scrapped many carb fuel nozzles. There was no need to buy expensive very high speed drill press.My cheapy US$100 China 13mm Drill Press drill these micro holes at the highest spindle speed. However I question the use of lubricants which may clog up and seize/break drills. Its true I have not use lubricants.

 

[Toolguy]

The best lubricant for all non ferrous metals is Tap Magic for Aluminum. It is great for Ali, but also for Brass, Copper, Bronze, etc.

 

[gus]

Hi Austin,
We have an intruder from Vietnam trying to get free advertisement ride. Very Sly. Cannot PM.

 

[gus]

I agree with Norman and others in this discussion to a large extent. And I'd like to add a point - temperature. you may control it strictly to ensure a good result. Because I don't know what kind of drill you are about to use, I can't offer you exact suggestions on temperature controller. you are welcome to write back. Jenny.

Hi Jenny Xie,

Please introduce yourself and your DIY Projects. I am given the impression you are barging into our HMEM Forum to advertise and sell products. Your ''hands on'' experience with micro hole drilling seems to be none. Many of us are highly experienced retired machinists. We have been drilling micro holes w/o temperature problems. Where did drilling temperature come from.

Regards from fellow Chinese now residing in Singapore.

Gus Deng aka Gus 邓