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Author Topic: Caldercraft Northlight Puffer with working Derrick Crane  (Read 87248 times)

andyn

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Re: I don't suppose I'm the first but .....................
« Reply #75 on: November 21, 2009, 01:06:05 am »

Every Rover ST1 ever made was slightly longer one one side that the other, we've all done it ;)

Just earlier tonight after making some toast I had phone in one hand and butter knife in the other, guess which one I threw in the sink? Luckily no water in it  {-)
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Bugsy

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Re: I don't suppose I'm the first but .....................
« Reply #76 on: November 21, 2009, 07:34:55 am »

Great comments  :-))

Note to self: put an arrow mark on the edge to be cut. :-)
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Roger in France

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Re: I don't suppose I'm the first but .....................
« Reply #77 on: November 21, 2009, 07:44:37 am »

I know the feeling well !

I now practise:
   
    Measure twice, cut once.
    Mark where to cut.
    Forget what the mark means.
    Start again.
    Get it wrong.
    Take the pills.
     Go and take a nap.

Roger in France

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omra85

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Re: I don't suppose I'm the first but .....................
« Reply #78 on: November 21, 2009, 09:07:04 am »

So, Bugsy in Vienne and Roger in La Vendee (surrounded by good, cheap wine), Andy swimming in Strongbow -
I think I can see a pattern emerging  O0 {-) {-)

How about "all cutting to be done between 12md and 3pm" which would coincide with the end of the DT's but before the start of the afternoon session  %) %)

CHEERS
Danny
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Bugsy

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Re: I don't suppose I'm the first but .....................
« Reply #79 on: November 21, 2009, 09:31:42 am »

I can 'hic' assure you Danny 'hic', that the wine 'hic' has nothing to do with it. 'hic'.
 %) %)
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andyn

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Re: I don't suppose I'm the first but .....................
« Reply #80 on: November 21, 2009, 01:55:53 pm »

Yesterday I was at the nice 12 year old scotch that someone bought me  ;)
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Corposant

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Re: I don't suppose I'm the first but .....................
« Reply #81 on: November 22, 2009, 09:10:13 pm »

Bugsy

At least the solution to your problem was "clear cut"!

For several weeks (on & off), I have been making some pulleys for mounting below deck.



Having just completed them, I realised the ones with a mounting bracket were u/s because the bracket was going to foul the thread on it's way round the sheave. Thought "Oh bother" (or something very similarilar).



One would have thought that the guy in the drawing office would have spotted that - but his "senior moments" seem to be coalescing these days.



Solution: Make new mounting brackets using thinner brass and reduce the thread on the blocks from 4BA to 6BA. So...

Mounted one of the blocks in the lathe to skim off the threaded section...but not enough material in the chuck for good grip, so tool tears it out and chews it up. Thought "Oh bother" (or something very similar).



Plan B: Start afresh with new rod. On cutting 6BA thread, find it's chewed up. Thought "Oh bother" (or something very similar). Turn down a bit more rod and try again - with the same result. Thought "Oh bother" (or something very similar). Close inspection of the die (c. 50 yrs old), reveals the reason - needs binning. Success with fresh die.

First attempt at milling the slot results in the work coming loose and the cutter destroying it. Thought "Oh bother" (or something very similar).



(I don't have a milling machine, so it's a bit hit and miss with the pillar drill.)

Make yet another block - O.K. this time round.

On making the new mounting brackets, I had to destroy the first one to retrieve the tap as the solder had caused it to jam. Thought "Oh bother" (or something very similar).



Eventually, however:



Just goes to show what can happen when a biochemist tries his hand at engineering!

Mike
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Bugsy

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Re: I don't suppose I'm the first but .....................
« Reply #82 on: November 22, 2009, 09:12:29 pm »

Brilliant !!
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Corposant

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Re: I don't suppose I'm the first but .....................
« Reply #83 on: November 22, 2009, 09:40:33 pm »

I thought that might cheer you up!

Mike
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Corposant

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Give me strength!
« Reply #84 on: December 09, 2009, 07:03:01 pm »

What could be simpler?



Two strips of brass, 2mm thick. Drill ten holes..........

First attempt abandoned when 0.5mm Tungsten Carbide drill shattered, leaving it's remnants firmly embedded. Thought "Oh bother" (or something very similar).

Second attempt resulted in the drill shattering in the tenth hole. Thought "Oh bother" (or something very similar). This time I spent the afternoon and the following morning attempting to remove the fragments as I had no more 0.5mm drills with a sturdy shank. Although successful, nasty things happened to the first of the HSS micro drills I used to enlarge the hole to 0.65mm, because of remnants of Tungsten Carbide were still in the wall. Thought "Oh bother" (or something very similar).

So...

Question: How do you drill small holes?

I used a pillar drill, white spirit as lubricant and was very gentle (or so I thought). Ordinary HSS micro drills are too "whippy" to keep the hole vertical (and too small to fit in the chuck).

Is there a better (i.e. tougher) alternative to Tungsten Carbide? Obviously cost is a factor but one wouldn't mind paying a bit extra for something more user friendly.

Mike
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stallspeed

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Re: Give me strength!
« Reply #85 on: December 09, 2009, 07:47:04 pm »

Have you tried titanium coated steel bits?
I got over the flex of small diameter bits on a dc powered drill by using a controller that monitors the drill motor current drain.The chuck
idles until pressure is applied at which the controller steps up the voltage to full.
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Liverbudgie

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Re: Give me strength!
« Reply #86 on: December 09, 2009, 07:56:38 pm »

1) Tungsten carbide drills are very hard and brittle therefore shatter easily and are not the best for this job as you have found out.

2) I take it that you do "pop" mark your holes before drilling so that the drill does not skate across the material when it first touches it.

3) If you your chuck won't take the very small sizes A) Buy a chuck that will or B) buy a GOOD quality set of pin vices which will take your small HSS drills and insert pin vice into your present chuck.

4) Don't use so much pressure let the drill do the work, if you have to use pressure then this means that the drill is blunt and needs sharpening or replacing.

5) Use a light machine oil to lubricate if you need to.

LB
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Corposant

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Re: Give me strength!
« Reply #87 on: December 09, 2009, 08:18:13 pm »

Stallspeed

I've got a few Titanium coated drills but none with reinforced shanks - I'll have a look on the Internet (and at the Model Engineers exhibition). Your drilling machine sounds fascinating!

Regards,
            Mike
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Corposant

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Re: Give me strength!
« Reply #88 on: December 09, 2009, 08:33:07 pm »

Liverbudgie

Many thanks for your thoughts. Yes, I mark small holes by "twizzling" a needle in a pin vice. My problem is not starting but finishing! The breakage occurs when the hole is quite deep, so it must be a problem with clearing swarf - even though I keep withdrawing the drill. I have never had a problem when drilling small holes using the lathe.

I have tried mounting a pin vice in the chuck, without success. The "Eclipse" one appears to be a reasonable quality - but perhaps you can recommend a better make.

Regards,
            Mike
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stallspeed

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Re: Give me strength!
« Reply #89 on: December 09, 2009, 08:44:51 pm »

I've managed to break a 2.5mm of those tungsten bits so the only use for them is drilling plastic sheet and printed circuit boards.
You get the titanium bits in kits along with the wood bits,masonry drills from the usual suppliers of 100 bits for 10.....Aldi,Lidl,Makro

The drill speed control was only a circuit idea from Elektor Electronics.It works on the same principle as an SLA battery charger where the voltage steps down to the float level when the current drain falls.

I have not used the drill controller since I got a pillar stand for a variable speed B&D drill.All it needs is a drill with decent torque and proper chuck that you can run at low speed or doesn't leave 2" of twist drill flapping about at 5,000 rpm.
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Corposant

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Re: Give me strength!
« Reply #90 on: December 09, 2009, 09:17:05 pm »

Stallspeed

Thanks for your advice. Elektor Magazine - that's a blast from the past! - I had no idea it still existed. I used to subscribe to it about 30 years ago! It was always very interesting.

Mike
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dodgy geezer

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Re: Give me strength!
« Reply #91 on: December 09, 2009, 09:52:37 pm »

I cheat.

I use dentist's burrs. My Dentist throws them out (to me :-)) after very few uses - they are very small and the shafts are very strong. I use them for pilot holes if I'm drilling anything small.
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stallspeed

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Re: Give me strength!
« Reply #92 on: December 09, 2009, 10:03:31 pm »

Stallspeed

Thanks for your advice. Elektor Magazine - that's a blast from the past! - I had no idea it still existed. I used to subscribe to it about 30 years ago! It was always very interesting.

Mike
There was a pcb pattern with it too.
I think it was in the bumper summer issue of the mid 80s.Although I'm a sad git hoarder,I keep them out in the loft. :embarrassed:
The magazine is still going strong and is available in cd format.
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gondolier88

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Re: Give me strength!
« Reply #93 on: December 09, 2009, 10:10:10 pm »

Centre drill then enlarge with the finishing bit, or if you find you are drilling holes in brass often of the same diameter invest in two or three reamers to finish off.

However addressing the original problem- drill bits shouldn't break if they are used under the right conditions- make sure the work isn't moveing, make sure the drill bit is drilling centrally- your centreing method isn't the best for drilling brass- you should mark the metal, centre pop with a centre punch the use a centre drill and expand with a reamer or drill bit.

Also, use fast spindle speeds, very slow feed rate and lubricate with something better than white spirit- brass creates a lot of friction when it's machined, and white spirit being petroleum based will evaporate at the point of contact as opposed to lubricating it- try proper cutting fluid, or try 3in1.

Greg
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Don't get heated...get steamed up!

HS93 (RIP)

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Re: Give me strength!
« Reply #94 on: December 09, 2009, 10:25:44 pm »

I do a lot of bras drilling (look at some of my postings) and have found a lot depends on the brass, I tend to use softer brasses the type sold to watch makers and have found it machines great another source is the likes of K&S from model shops, I use the tin coated drills from
 http://www.arceurotrade.co.uk/Catalogue/Cutting-Tools/Twist-Drills/Drill-Bits---TiN-Coated     
for the last few years and have had good results.

peter
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stallspeed

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Re: Give me strength!
« Reply #95 on: December 09, 2009, 10:29:54 pm »

- drill bits shouldn't break if they are used under the right conditions-
Mike's drill bits are probably ex-equipment 1/8" shank solid tungsten bits from circuit board fabricators.They are very brittle.I broke a 2.5 mm one drilling plywood.

I don't see any sign of JB Cutting tools any more.Does anyone still sell these tungsten bits for sale at shows?
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Corposant

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Re: Give me strength!
« Reply #96 on: December 09, 2009, 10:58:04 pm »

Dodgygeezer

Dentist's burrs sound great - but do they go down to 0.5mm? That reminds me, it's about time I found a dentist (last visit 1989!!).

Mike
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Re: Give me strength!
« Reply #97 on: December 09, 2009, 11:00:41 pm »

Stallspeed

Thanks for the info about the mag. - I've had a look at their website.

Yes my drills have 1/8" shanks - bought from Horley Drill Service (free postage!).

Mike
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Re: Give me strength!
« Reply #98 on: December 09, 2009, 11:06:10 pm »

Greg

Thanks for your tips. Centre drill - no problem, I've got a small one but the breakage comes later! I think your advice about lubrication may be the answer. I chose white spirit because it works well with aluminium. I haven't got any cutting fluid but plenty of 3 in 1!

The mind boggles at using a centre punch for starting a 0.5mm hole! I'll stick with the centre drill!

Mike
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Re: Give me strength!
« Reply #99 on: December 09, 2009, 11:10:06 pm »

Peter

Good to hear from you again - and thanks for the info. I had a quick look at the arceurotrade website but couldn't see any at 0.5mm. I'm hopeful of the Model Engineer's exhibition - and also hoping for more boats than last time!

Mike
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