10BA clearance holes

I want to make some 10BA clearance holes in a piece of spring steel for the support of a pendulum.
Do I need to anneal first and reharden afterwards, or is there a better way?
(Ham Radio project - chinese copy of a Vibroplex Morse key)

gareth wrote:
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I think this would depend on what state the steel you have is in and what you require it to do. I have a few thicknesses of carbon spring steel , IIRC 1.5mm, 2.0mm and 2.5mm, and it is in an annealed state as delivered and that is fine for my use. As such it is easy to drill and machine so for your use you may be able to just drill the material you have as is, you should though take advice from the suppliers as to it's strength and therefore determine a suitable cutting speed for the material you have.

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Thank-you David. Unfortunately the material I have to hand is a Stanley tape measure that has pinged irretrievably out of its case.

On 08/03/12 20:15, gareth wrote:
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I recently repaired (well, last year) a Gents Pulsynetic, which had a broken pendulum support spring on receipt. Just measured up the spring, thickness and width, and then bought a cheap clock spring via ebay, where there is quite a selection usually.
A drill wouldn't go near it, so I did anneal before drilling, then hardened and tempered afterwards...
Regards,
Chris

gareth wrote:
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If the leading end is still intact you might consider using that. If the hole needs opening out then a tapered grinding tool from a micro drill could be considered.

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Excellent idea.
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Another good point. (Apun my word!)
Thanks to all those who replied, I have enough to be getting on with now.

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Carbide drills will go through spring steel easily without the need to anneal, though you would be advised to sandwich it just the same as any other thin metal being drilled.
Cliff Coggin.

On Fri, 3 Aug 2012 21:21:45 +0100, "Cliff Coggin"
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Carbide drills in 10BA clearance...? (that is ~1.7mm diam...)
The traditional method, given that it is a PIA to drill thin material, is to make yourself a hardened steel punch. If you want to do the thing properly, then make a matching punching block (think paper hole punch) that wil guide the punch & also help to make the punch cut cleanly, but you can get away with punching through onto soft material (aluminium block, hardwood end-grain).
Regards, Tony

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Why not? I use carbide drills as small as 0.85 mm to drill spring steel clock suspensions and the arbors of French pendules.
Cliff.

On Thu, 9 Aug 2012 18:50:46 +0100, "Cliff Coggin"
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Apologies - slight brain fart there - was thinking carbide tipped, but of course solid carbide comes in smaller diameters.
Regards, Tony

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This sort of thing http://www.drillbitcity.com/catalogue/10_piece.asp but also available on ebay. I used them for (amongst other things) drilling holes in ball bearings
Dave

On 08/10/12 09:58, dave sanderson wrote:
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But this involves added expense :-). If you are making batches, having the right tools is probably a good idea, though carbide drills, at least the pcb drilling types, are very fragile, ime. A stellite drill may be a better choice, though it's years since I even saw one.
For a one off, at no expense, it takes only minutes to anneal, drill, then re harden and temper and it costs you nothing...
Regards,
Chris

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Plus 5 hours of planning if you've never done it before!

On 08/11/12 17:22, gareth wrote:
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Just how long does it take to cut a bit of spring steel strip, warm to red heat in gas blowlamp, allow to cool, centre punch, drill, warm to red heat and quench, polish and temper to desired point ?. About 10 or 20 minutes should get the job done.
There's a tendency to overcomplicate all sorts of stuff these days, when alls that's needed is a bit of common sense...
Regards,
Chris

On 11/08/12 19:00, ChrisQ wrote:
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Find strip Find saw try saw find another saw try new saw find dremel fit rotary abrasive blade cut strip
warm to
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Find blowlamp. find (empty) fuel canister go out and buy new fuel canister heat strip to red heat ooops, too hot - cut new strip. heat to red heat
allow to cool,
easy, eh?
centre punch,
find center punch punch turn strip over punch in correct position on other side
drill,
find hss drill try to drill darn, cooled too fast, curled up when drilling. Never mind, the hole would have been in the wrong place anyway.
find Dremel (I _knew_ I shouldn't have put it away) cut new strip heat to red heat allow to cool drill hole.
warm to
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ooops, nothing to quench in - get water. oops, left in flame too long. start again
ooops, no strip left. Go out and buy new strip. cut new strip heat to red heat allow to cool drill hole. heat to red heat quench
polish
find wire brush for Dremel oops,broke quenched strip, too brittle, Gave up on polishing idea.
cut new strip heat to red heat allow to cool drill hole heat to red heat quench
and temper to desired point
temper temper!
ooops, no strip left. Go out and buy new strip. cut new strip heat to red heat allow to cool drill hole. heat to red heat quench temper
About 10 or
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ITYM 10 or 20 days?
:)
-- Peter Fairbrother
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On 08/11/12 21:15, Peter Fairbrother wrote:
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Well if you are that cack handed, then you shouldn't have started :-).
All kinds of stuff can get in the way of getting a job done if you are really determined, but it's not as though you need a first class machine shop to do a job like that. Even if you haven't done such a job before, you will learn and know how next time :-). Sorry, but it's school metalwork class level.
Have you checked the price of small dia carbide drills recently ?. 1.5mm tungsten carbide drill, between 5.00 and 30.00 ukp each, though ebay will be much cheaper. Not the sort of job you could do with a black and decker hand drill either...
Regards,
Chris

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If you are paying those sort of prices Chris, it is no wonder you prefer an alternative method of making the hole. I buy carbide drills 50 at a time for less than a pound each in the expectation of breaking at least one on every job. The saving of my time makes them well worthwhile.
Cliff Coggin.

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Thanks for all the contributions, especially the sympathetic trials and tribulations from Peter, but a "coward's way out" has now presented itself, and it is this, at the risk of SWMBO instituting divorce proceedings, to find the largest dressmaking needle or darning needle in her sewing box, which comes closest to the desired hole size (test hole drilled in a bit of scrap ally) and, being hardened steel of the right size, bang it through.

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If you are going to pierce the steel with what sounds essentially like a nail, then it is likely to split, or at best leave a ragged hole that will need to be fettled. You really need to cut the hole with either a drill or a punch.
Cliff Coggin.

On Sun, 12 Aug 2012 11:14:24 +0100, "Cliff Coggin"
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Why is everyone getting so exited about this job? Spring temper is in the early 40's HRC. Just drill the darn thing with any drill that's not made out of butter!
Mark Rand RTFM