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Drilling hole of 0.0310" with deepth 0.91" of AISI 304L

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Junid Lelawe01/12/2011 14:06:24
2 forum posts
I need your help for drilling AISI 304L.
The holes diameter is 0.0310" ± 0.0030" and the holes depth is about 0.9100".
I found a tool of Walter which has a spiral length of 0.98" and total length of 1.81".
Walter catalog number is A1511-0.8
The questions are:
1. Is it possible to make this hole using Walter tool?
2. What is the cutting data I should use?
3. What is the machining strategy?
4. Should I use more tools with different diameters in order to get this hole?
David Littlewood01/12/2011 14:35:06
533 forum posts
You may find this company's website useful:
They do micro drilling down to 0.05 mm, and sell a variety of drill bits (and other tooling) as good as I have seen anywhere. Their mail order service is very good.
JasonB01/12/2011 16:36:34
18924 forum posts
2082 photos
1 articles

Edited By JasonB on 01/12/2011 16:37:07

Jeff Dayman01/12/2011 19:52:19
1896 forum posts
45 photos
What model are you making that requires the .031 holes .98 deep in stainless?
Are you doing this in your home workshop?
You will need a drill press or mill with very high speed.
Stub Mandrel01/12/2011 20:47:56
4311 forum posts
291 photos
1 articles
In almost any other material I would use a new 1/32" hss drill and expect to get an acceptable result.
Stainless=all bets off
chris stephens02/12/2011 00:27:22
1045 forum posts
1 photos
Hi JD,
Beg to differ, I have drilled 0.8mm holes in, if I remember correctly, Silver Steel but may have been MS at 800RPM which was the top speed on my lathe. High speed when drilling is not quite as important as some may think.
David Littlewood02/12/2011 01:06:31
533 forum posts
With very small drills the recommended speed for drilling actually decreases. This is because the very flimsy drill is likely to flex, and at high speeds can actually break. You do of course have to decrease the feed rate accordingly.
Andrew Johnston02/12/2011 10:15:14
5674 forum posts
656 photos
Posted by David Littlewood on 02/12/2011 01:06:31:
With very small drills the recommended speed for drilling actually decreases. This is because the very flimsy drill is likely to flex, and at high speeds can actually break. You do of course have to decrease the feed rate accordingly.
Err, so how do CNC drill machines for PCBs get away with running small drills at 100,000rpm? As an example my standard signal via is 0.3mm finished, so drill with a 0.31mm drill.
PS: I expect that the OP could achieve what he wants, but he might break a few drills in the process. If he has more than a few holes to do he'd be better off finding some-one who can EDM the holes.
Ian S C02/12/2011 10:16:08
7468 forum posts
230 photos
For stainless, and that size hole 5000 would be about max rpm, 1000 rpm would be quite OK. You must keep the drill cutting when its in contact with the metal.Initial cut, about 3 dias, 2nd 2 dias, after that just a few thou a time, and withdraw the bit completely each time, its going to take a while to get through. If its a through hole, place a bit of steel under it, and drill into that, it will prevent the drill catching, and breaking as it exits. The drill must run concentricly, or you will break the drill. Was looking at another site, someone said,"you can buy holes down to .005", you drill the initial hole 1/16", then press the inserted hole into the drilled hole". Ian S C
David Clark 102/12/2011 11:01:43
3357 forum posts
112 photos
10 articles
Hi Andrew
How do they get away with running at 360,000.
That was the speed of the drilling spindles we were making.
Thye were working on a 500,000 RPM version when I left the company.
regards David
Jeff Dayman02/12/2011 12:55:04
1896 forum posts
45 photos
I was holding back a little on the details of drilling these holes. The original poster's tone and questions are similar to many enquiries I've seen from southeast asia to professional machining forums.
If the OP is making a hobby enquiry for a model or tool and shares details about what it is, I am glad to help.
If the enquiry is to help train aerospace machinists or weapons specialists in foreign countries - not willing to help.
The hole specs (small dia very deep, in stainless) seem strange for a model, the kind of thing to be avoided in hobby work. However I've seen lots of holes like that, some even smaller and deeper, in aero and some weapons parts.
Just a little cautious is all - hope the OP clears up what he is doing.
Richard Parsons02/12/2011 14:49:03
645 forum posts
33 photos


I sympathise with you. Back in the U.K I started to make models of the weapons of the British army in 1/10 scale. Ok I made the Baker rifle of the early pattern bore 1/16” 3.2” long. The New land service musket had a bore of 0.075” by 4.2”deep. The Brunswick is unfinished because Hungarians chopped up my block of Lime wood for kindling even though it was locked in my shed. I chickened out at the. 577 Enfield (long land service model) where the bore is 0.058”dia and the length is 4.8 to 5”. How I did it on a Myford is my secret.

By the way the OP does not say what hole is to be in.

David Littlewood02/12/2011 15:42:23
533 forum posts
We may be talking about two different things. High speed micro drilling requires a machine with very precise bearings, and a TIR of less than 0.0001", and which can control the downfeed to avoid bending the drill (which would cause it, at those speeds, to tie itself in knots) ... but not too slow such that it work-hardens the metal. Feeds around 1 micron per revolution, and automatic peck-drilling to remove swarf.
For the majority of us, using a standard drilling or milling machine, with no special bearings and hand feeds, the recommendation (and it came from a maker of micro drills) is that maximum speed should go up to 20k at 1 mm, and reduce below that, slowly at first but quite quickly below 0.5 mm. My drilling is done on a milling machine with a top speed of 2,000 rpm, so I don't have to worry about it - just use top speed, but if you have a high spped drill it may be worth checking the position.
Donald Wittmann02/12/2011 15:46:23
40 forum posts
304 ss is terrible stuff ,could you not substitute it for 303? even 316 is better than 304. That type is really a swine to machine. I have turned it many times over the years and have yet to hear of anybody who likes the stuff. I would be interested to know what properties of 304 is required for your model.
Ps Walter/Titex are amongst the finest cutting tools available expensive but first rate gear.
Jeff Dayman02/12/2011 16:43:10
1896 forum posts
45 photos
Richard Parsons said:
"By the way the OP does not say what hole is to be in. "
Yes that is right Richard, and that is my point - until we do know if this is a model or home shop job, I'm cautious about offering too much detail.
Stub Mandrel02/12/2011 19:47:57
4311 forum posts
291 photos
1 articles
A colleague of mine had a friend who worked for a British engineering company.
One day his team recieved a sample 'the finest tubing in the world' from a rival American company.
Apparently they sent it back, with a sample of their own tubing threaded through it.

Edited By Stub Mandrel on 02/12/2011 19:48:37

Anthony Knights02/12/2011 20:14:18
427 forum posts
185 photos
I dont know what the material you are talking about is like but there are solid tungsten carbide drill bits (for drilling PCBs) available close to the sizes you are talking about.
Junid Lelawe04/12/2011 08:47:57
2 forum posts


This tube is for picking and placing tool for the semiconductor industry. It picks up chips and dies and then places them.

Today we make this tool from two pieces because there is a hole of 0.0310" in one side, and a hole of 0.0080" in the other side.

We buy a part with through hole of 0.0310" and brazing this part with the other part (which hasn’t a hole) and then making the hole of 0.0080".

We want to make this tool from one piece so I have to drill the 0.0310" and then drill the 0.0080" from the other side.

The material and the holes sizes are according to customer request and can't be changed.

I have a Schublin turning machine with 4000 rpm max.

For more information about our company-


NJH04/12/2011 10:10:41
2314 forum posts
139 photos
Well Jeff
It seem that you have this right - the information IS for commercial application. If the OP has gained useful information from this thread then maybe mpptools would like to make a donation to a suitable UK charity - at a rate suitable for the employment of 10 consultants!
Richard Parsons04/12/2011 11:32:00
645 forum posts
33 photos


From our collective replies you should be able to identify those who can solve your problem. May be you should use the private mail system to communicate with such people. Do not include me my methods are far too slow and clumsey.


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