Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length.

[aestus57]

 

Has anyone got any tips on how to drill small diameter holes in Brass.

I've been trying to drill a series of 1mm dia holes in some 1/16" thick brass plate, but its costing me a fortune!! as the drill only lasts for 1 hole and half way through the next.... at £1.00 per drill I don't think I can afford to do the job.

I've got a bench pillar drill which will go uo to about 3000rpm but I seem to burn the drill out quicker at that speed, I've also got a Dremel, but thats even faster.  I always thought the advice was - the smaller the drill, the higher the speed-  I've also had a go at sharpening the drills with a small grindstone in the dremel but again have had no sucess, don't think my old eyesight is up to such fine work!

Help pleeeeaaase !!!!!       

[Bunkerbarge]

Faster yes, but don't get carried away.  Just a couple of thoughts:

1) Use top quality drills
2) Do not force the drill, gentle pressure
3) Clear the drill regularly, i.e. lift the drill out to prevent the swarf clogging and overheating the drill.
4) Use a coolant/lubricant.  Try with something as simple as a light oil such as 3 in 1 to start with.
5) If you can successfully sharpen a 1mm drill you are better than any other engineer I have ever come across.  I wouldn't even try!
6) If you are cutting a lot of holes you may well be able to purchase drills with a nomenclature specifically for cutting brass.  The tip angle for steel is 118 degrees but it is different for brass and all drill bits you buy in a shop will be for steel.  Have a look around for brass drilling bits.

I'm sure that as soon as Bogstandard sees this he will have something more useful to offer!!

[aestus57]

Thanks for that Bunkerbarge,  I was wondering about using a coolant but wasn't sure that it was right to do so with brass, I'm sure  I've heard of using "parafin" but thought that was with Aluminium.

I'll give iy a try though and post the outcome

Thanks

[Malcolm Reade]

No coolant needed when machining brass.

Malc

[Circlip]

Sorry BB, Malcolm is correct, yer don't need lube when drilling brass, you're more likely to clog the drill at that dia. One other slight problem is that the leading angle on drills is too acute for drilling brasses, that's why when the drill breaks through, the bit of metal grabs and either runs up the drill or spins out of yer fingies and acts like an orizontal circular saw blade. It's eyeglass work to gently stroke the vertical cutting face square to stop the drill "Biting" and at 1mm Dia. you need to be rotating at the Dremel speed but with the drill firmly mounted so that you can drill vertically with a pecking motion. A small bristle brush is handy to keep the end of the drill clean.

   Regards  Ian.

[Proteus]

I buy my drills from the link below very fast service,I tend to use the tin coated drills five for £1 .50 ,I drill a lot of brass, just get your drill press fast as you can , if it's the likes of K&S brass they cut like butter,  I got some so called brass from B+Q and its a bit hard, there are also cobalt drills there for 50p each

http://www.arceurotrade.co.uk/Catalogue/Cutting-Tools/Twist-Drills/Drill-Bits---TiN-Coated

http://www.arceurotrade.co.uk/Catalogue/Cutting-Tools/Twist-Drills/Drill-Bits---Cobalt


Proteus

[craftysod]

No one has mentioned the pressure that is put on the drill bit,i have found out as many have,the more pressure put,will wear out the drill and cause heat.
As i have been told let the drill do the work,as we all have found out,we want it done now.
Just my sixpence worth
Mark

[aestus57]

Thanks Proteus,

The Brass I'm using is not the best quality.  It's a peice which used to be the kicking plate at the bottom of a door, lots of impurities and hard spots.

Thanks for the links, I have been using the tin coated drills from another supplier at 99p each!!!, think I'll give the cobalt ones a try.

Regards

Peter

[Bunkerbarge]

No one has mentioned the pressure that is put on the drill bit,i have found out as many have,the more pressure put,will wear out the drill and cause heat.
As i have been told let the drill do the work,as we all have found out,we want it done now.
Just my sixpence worth
Mark

Read my post.

[carloshenckes]

softer the material, higher the speed. some coolant will do any damage...

[bogstandard]

If it is normal yellow brass you should be able to drill hundreds if not thousands of holes with one drill.

Your material might in fact be a phos bronze derivative, a nice coppery colour.

The easy way to check, is that when drilling, if you get any spiral chips at all, it isn't normal yellow brass, but most probably a material that has a little more copper in it. Normal brass should come off like a fine dust.

If it comes off in spirals, reduce speed considerably and use cows milk or tallow (lard will do) for a lubricant.

A very good source for drills, especially stub drills (much better when drilling smaller diam holes) is here for ground flute

http://www.leofixings.com/fixings-products_Drill+Bits_HSS+Ground+Flute+Metric+Jobbers+%28Bulk%29-10-135.html

or here for Jobbers (ideal for your sort of work)

http://www.leofixings.com/fixings-products_Drill+Bits_HSS+Ground+Flute+Metric+Jobbers+%28Bulk%29-10-135.html

And remember, these prices are for boxes of 10, but you will need to add vat and postage. I usually make up an order of about 100 drills of different sizes to make them more cost effective.

Hope this helps

Bogs

[Floodtide]

I would stabilize the material before doing any extensive work on it. Heat it up in the oven for 30 minutes at 350-400 degrees and then let it cool down slowly. It helps to take out stresses in the material when you are trying to do fine work. I don't see the need to run the bit at such high speeds either, on a drill bit so small, I would try 800 rpm and go up or down in rpm as the bit will stand it.  Keep a constant stream of cool low pressure air on the work to keep chips clear and to keep the heat down at the face of the bit. You didn't say what thickness material but there are more tools to consider besides a 2 flute drill bit at 118 degrees. Feed rate on a small bit is very hard to feel so much more patience needed.