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Member postings for David Colwill

Here is a list of all the postings David Colwill has made in our forums. Click on a thread name to jump to the thread.

Thread: Workshop content
08/10/2021 12:44:02

Can you give us a rough idea of where you are?


Thread: Hardinge HLV H
01/10/2021 07:25:09
Posted by Pete Rimmer on 27/09/2021 19:30:38:
Posted by David Colwill on 27/09/2021 07:20:25:

I believe that there is a difference between the British and American built machines. The British Machines have a 4 degree taper as opposed to the 3 degree 59 minute 30 second of the American machines.

Not a problem if you are working to the taper on your machine.


I make it roughly 0.00017" difference which is no difference at all given that the big and small ends have a 7 tenths allowance on the drawing.

I have to say that I never bothered to work out what the difference was. I just knew that the British machines are 4 degrees.

Sorry for making everyone rush for their calculators.


Edited By Pete Rimmer on 27/09/2021 19:34:35

27/09/2021 07:20:25

I believe that there is a difference between the British and American built machines. The British Machines have a 4 degree taper as opposed to the 3 degree 59 minute 30 second of the American machines.

Not a problem if you are working to the taper on your machine.


23/09/2021 21:35:24
Posted by Mark Rand on 23/09/2021 20:26:43:

It's very easy to turn the hardinge nose taper to make chuck back plates.

Indeed it is.

That was this mornings job, spurred on by this thread.


23/09/2021 07:36:32

I have never seen a chuck on a Hardinge backplate in good condition. Like Pete above I have the older HLV. This had a chuck with it that was worn well past the dangerous to use stage. The taper mount was built into the chuck but I was able to machine away enough to allow me to mount a Chinese 100mm 3 jaw chuck which works okay for the odd time I need it.


Thread: What to drive a J & S with ?
09/09/2021 21:33:56

I run mine on a rotary phase converter with no problems.

It may help if you can answer the following question.

Are you going to be working for NASA?

If the answer is no, then a rotary phase converter will be fine.

If the answer is yes then get a brand new surface grinder , the correct supply and stop trying to be cheap!


Thread: It would be nice to know........
09/09/2021 09:51:02

When power tapping would be the obvious one.



Thread: 9/32 hex steel bar
03/09/2021 08:32:54


I have asked a couple of my stockholders and they don't keep it.

West Midlands Bright Bar was mentioned as worth a try.


Thread: Marking steel
01/09/2021 14:07:50

I have a need to be able to mark steel. Paint markers are okay but on my Coventry die heads this soon wears off. I don't want to etch or engrave and whilst I could fix some kind of tag this seems like bother.

The idea came to me that if I put some Blackfast solution into an empty marker pen, I could end up with a pen that would produce black writing that would not easily rub off.

It works... Sort of!img_20210901_134235_004.jpg

There are some issues.

Firstly it is too thin!

Secondly it doesn't stick very well.

The only thing I had to hand to try and thicken it with was some clay. This produced the result in the photo. I wiped the surface with IPA (not the bitter!) Then wrote on the steel. I waited about a minute and wiped it clean.

The writing can be taken off with scotchbrite but would appear to be pretty resistant otherwise.

Does anyone have any ideas on how to improve this?


Thread: One for the youngsters
28/08/2021 06:50:25
Posted by Bob Stevenson on 28/08/2021 06:36:35:

They no longer allow conventional clock faces in school exam rooms because the 'strange' & 'weird' face adds considerable stress to the kids......

I think I need something solid to bang my head against!

Thread: Is there a Gitzo tripod expert in the house ?
24/08/2021 14:13:02

This sounds like the sort of problem that could be solved with a 3D printer.

A 3D printed 2 foot stillson would certainly solve the problem whilst producing gasps of horror from anyone watching you use it!


Thread: Chinese "K40" laser
21/08/2021 12:25:29

Having done various trials with this i am inclined to agree that it isn't really practical.

My first attempt did mark a piece of graphite and although it wasn't deep it didn't rub off. However the surface of the graphite was cut with a bandsaw and in reality the ridges of the cut were protecting the marking.

Another go with a smoother surface produced a similar marking but this time it was easily rubbed off.

Using slower speed for the engraving didn't make any difference nor did using air assist.


Thread: 5C collet internal thread
19/08/2021 17:17:04
Posted by Ian P on 19/08/2021 15:38:00:

David, how did you hold the collet?

The collet in question was 24mm.

I turned a piece of bar to 24mm and then tightened a 5C collet block on to it.

It looked rather Heath Robinson but worked very well.


Thread: Chinese "K40" laser
19/08/2021 17:10:48


I have one that is set up and ready to go.

I couldn't say what the true power is but suspect it isn't 40W.

PM me contact details as i do have some graphite and may be able to do a proof of concept.



Thread: 5C collet internal thread
19/08/2021 14:02:24

The other day I needed to do a job that would involve a 5C collet with a stop.

Sadly my 5/16 collet did not have the internal thread for the stop to screw in. I do own the type that expands into a plain bore but don't like it.

I thought that I would have a go at threading the collet (a genuine Hardinge) but didn't think I would stand much chance.

I used a generic 60 degree 16ER type insert.

It was in the end very easy.


Thread: Royal Mail Tracking Numbers!
24/07/2021 21:09:32

I use a few delivery firms including Royal Mail and can safely say the they are all having problems. Not only are they having problems with staff shortages but the demand for delivery is higher.

I should say the my experience with Royal Mail and tracking numbers is that they can be wrong. Either saying that parcels have been delivered when they haven't or vice versa. On the plus side most parcels do seem to get there in the end but a wait of 4 / 5 weeks doesn't go down well with my customers and since I'm not about to start my own nationwide delivery service there isn't much I can do about it.


Thread: Fractal vice
24/07/2021 09:46:37


What does the "B" in Benoir B Mandlebrot stand for?

Answer Benoir B Mandlebrot.

I'll get me hat!

Thread: How Elgin made Jewels for Chronometers
23/06/2021 07:35:20

Alas I have only watched the first ten minutes as I have work to do but it is saved for later.

Thank you.


Thread: Lack of material and prices
11/06/2021 09:49:18

Yet another side to this is that some companies scaled back production thinking that the pandemic would cut demand. In truth the opposite has happened because no one went on holiday and instead many have spent this money on home improvements. The building trade is busier than ever.

A sadder and more serious (to us anyway) calamity is the Liberty Steel troubles. There is still no end in sight with this. They produced all of the EN16T (which I use a lot of and there is no real European equivalent), all the imperial hex sizes and most of the EN1a.

Even if there a buyer is found and production resumes (unlikely with a serious fraud investigation ongoing) it will take 6 months to be back to full swing.

It will be a very sad day indeed if this is not resolved!


Thread: Hydrogen home heating
19/05/2021 08:46:16

Don't worry.

Fusion is only 5 years away smile p

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