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Member postings for S.D.L.

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

Thread: O ring sizes?
10/10/2019 21:19:05

Seen down to 0.1mm cross section x 0.3mm OD



Edited By S.D.L. on 10/10/2019 21:19:24

Thread: ACME thread identification question.
14/09/2019 22:38:25
Posted by Michael Gilligan on 14/09/2019 22:29:53:
Posted by S.D.L. on 14/09/2019 22:09:11:

A lot of leadscrews are cut by thread wirling, The most accurate are ground.


Yes, Steve : But the Boxford drawing that Pete posted explicitly states 'Plunge Roll'


Yes but that’s for imperial ACME, they may have done the metric by another method?


14/09/2019 22:09:11
Posted by Michael Gilligan on 14/09/2019 19:07:15:
Posted by old mart on 14/09/2019 18:58:08:

Thread rolling is a specialised process, which most firms would sub out to the experts.


But why would those experts want to roll an ACME thread-form to Metric dimensions.

True ACME is [to the best of my knowledge] exclusively specified in Imperial units.

... If I am wrong; would someone please tell me


A lot of leadscrews are cut by thread wirling, The most accurate are ground.


14/09/2019 22:04:13
Posted by Pete Rimmer on 14/09/2019 21:44:44:

I guess you'd need to find an ex-employee from the factory for that, or a drawing.

BTW I had an Denford TDS1 and the cross slide thread on that was clearly cut (or at least finished) with a die. The marks where the die stopped were plain to see.

How are you sure it was a die? Threads cut with an Anjest attachment have a run out like a die as do modern CNC threads no need for an undercut with either.


14/09/2019 22:01:42
Posted by Michael Gilligan on 14/09/2019 19:01:53:
Posted by S.D.L. on 14/09/2019 16:52:51:

Halifax Rack and Screw make precision leadscrews, Used to serve the machine tool industry.

I know they will also make Ba$tard sizes as where I work they used to make us a 16mm x metric pitch ACME in stainless steel.


Perhaps you could explain then, Steve [please]

Why would anyone choose to specify 16mm x some metric pitch in ACME form rather than Metric Trapezoidal ?

[my brain hurts] ... Is it just to make it difficult for customers to second-source spares ?


I always put it down to one of my predecessors being stupid. I was never able to find out why but my guess was they didn’t know about trapezoidal.

Sometimes things conspire against you I designed a pneumatic cylinder 150mm Diameter with a screw on end, It was supposed to be 150mm x 2mm or something similar, had been told we had got the internal and external tips, but we hadn’t got the Internal so it was done 150mm x 12 TPI Whit. I calculated the dimension for 3 wire on the external thread and we made that fist then did the internal thread to fit.

In most of these cases its ignorance or expedience.


14/09/2019 16:52:51
Posted by Michael Gilligan on 14/09/2019 09:50:06:
Posted by SillyOldDuffer on 14/09/2019 09:16:20:
Posted by Michael Gilligan on 13/09/2019 23:11:29:
Posted by Pete Rimmer on 13/09/2019 11:16:48:

The Boxford drawing specifies that the threads are plunge rolled - for the imperial leadscrews at least.


Did they do the thread rolling in-house, or sub-contract, I wonder. dont know

... either way [if I understand the process correctly] that would require a serious machine and long dies.



Buying parts in has long been a common commercial arrangement. [ ... ]


Quite so, Dave ... and the Pope is usually a Catholic devil

I am interested in how and where the Boxford screws were made, because that knowledge might help us understand why they chose to use a 'bastard' thread.


Halifax Rack and Screw make precision leadscrews, Used to serve the machine tool industry.

I know they will also make Ba$tard sizes as where I work they used to make us a 16mm x metric pitch ACME in stainless steel.


Thread: Taper pins
30/08/2019 18:40:17
Posted by Boiler Bri on 30/08/2019 17:40:33:

Right i am slightly confused, do we use a taper drill or not?


If youre doing a few just use the reamer if youre doing a lot get the drills, its just the same with morse taper sockets.


Thread: Dam Solution?
07/08/2019 16:27:18
Posted by DMB on 07/08/2019 15:41:25:

Lots of things have been done by cheapskate methods, including that dam. Long term, they should rebuild it properly from the ground up in massive rocks which cannot be dissolved/washed away like mud.Fill gaps with concrete, job done and 'everlasting.'

Where are Dams built like this not a construction i have heard of?


06/08/2019 18:50:46
Posted by old mart on 06/08/2019 17:41:29:

I noticed in the Wikipedia entry for the dam that a proportion of the water feeding the dam is diverted into the stream alongside. I assume that steps have been taken to divert all the incoming water into the stream and that it can handle the increase.

The first Chinnok loads before they started on the slipway were to dam the infeed.


06/08/2019 08:41:33
Posted by peak4 on 05/08/2019 19:26:08:
Posted by JA on 05/08/2019 19:10:53:

I have tried to find the capacity of the pumps being used without success. 24 million litres/hr sounds like an awful lot. However if the bore of the pipe was 1" the flow would be 3.7 gal/s which seems sensible.


These from Hereford and Worcester are 7000 litres / Minute apparently

i.e. 420,000 l/hr and there were at least 23 of them working at one time so about 9.6 million l/hr


Edited By peak4 on 05/08/2019 19:27:11

At 7000l/s the velocity in the 150mm / 6" pipe the pump sets have, would be about 1.13m/sec. ie in the normal range of 1 to 3m/s pipe velocity.

for the syphon at 1480 gps is 88800GPM so allowing 18" pipe (500mm as suggested the velocity would be 35m/s

So two questions wink

how thick does the pipe have to be to resist erosion?

How do you stop it working as a water jet cutter at the discharge?

And in the time we have been speculating on this they have mobalised the pumps and drained 50% or the water


03/08/2019 21:24:15
Posted by Neil Wyatt on 03/08/2019 20:24:59:

Rather than decrying Wikipedia as 'inaccurate why not take a look at some of the plentiful references in the article?

Past research has shown it to be no less accurate than the Encyclopaedia Britannica.


P.S. Looks to me that the pumps are in the floating yellow bits (sorry Original thought was wrong...)

Edited By Neil Wyatt on 03/08/2019 20:26:32

They are

Come from the High volume pump sets they have been sending.

The are 50 + sets distributed around the fire brigades that do about 420 m3/hr

High Volume pump pods

Saw somewhere they have 16 sets in place now


Thread: Laser cut plates
02/08/2019 21:40:04
Posted by Fowlers Fury on 02/08/2019 20:50:12:

34046 - Have you checked with Malcolm what excess - if any - he requires to be added to your required dimensions? He's done several laser-cut items from my CAD dwgs and he's queried some of my dimensions thankfully !

The laser-cut edges from the company he used for my items were "rough" and hard. They needed draw filing smooth with a diamond file, I accept that techniques may have moved on in the last couple of years but a small dimensional excess was incorporated to allow for the smoothing-off.

If you find a laser cutting company that cuts a lot of stainless steel they wil use a purge gas and the edges will be clean with no oxide.


Thread: What milling tip do I need?
21/07/2019 21:49:07
Posted by Alistair Robertson 1 on 21/07/2019 21:05:20:


I have an 80mm dia. Facing milling cutter with 7 insert locations.

It came to me in a box with a lot of tooling at a local auction a couple of years ago. I have just got to the bottom of the box recently and it was a pleasant surprise as it is in excellent condition, BUT there are no tips to fit it, but the screws are there and don't look as if they have been used!

The only identification is the code A241.80.R.07 The rectangular tips look to be about 12mm x 8mm x 5mm thick with a 3.5mm screw hole. (These sizes are approx)

I have been in contact with several tooling suppliers but as yet none of them can identify what tips I need. I may have to go to a few suppliers and ask to see if I can get something to fit, but perhaps some of the very knowledgeable folks on this forum can identify what I need.

Its Supplied by WNT and new would set you back £418 without discount

Shell end mount needed is 27mm

Insets are LD 1504

WNT will sell to anyone ring up place an order pay by card and call the company hobby. My wife has an account for getting christmas presents etc


Thread: Do you wear a mask grinding HSS tool bits?
28/05/2019 08:58:42
Posted by Martin Kyte on 28/05/2019 08:48:13:



Cobalt would be one good reason.


Thread: Threading 1/8 stainless steel
01/05/2019 11:52:24
Posted by Eric Cox on 01/05/2019 10:14:14:

The die is mounted in a die holder in the tail stock.

plan of attack is,

clean with acetone

open die fully

use aluminium block

plenty of Rocol


Check how central the die is in the tailstock die holder. Some have large clearance bores for the dies to be split open and when used push the die up to .75mm (20thou) off centre which is a lot on basically a 3mm thread.

If this is a problem add 3 tapped holes to die holder at 90 degree intervals so that die can be centered , can then be closed up using two side screws.


01/05/2019 08:18:04
Posted by Eric Cox on 30/04/2019 16:04:52:

I'm trying to cut a 5BA thread on 1/8" stainless steel rod held in the 3jaw lathe chuck. The die starts to cut then the rod slips in the chuck marking the rod. Would I be better off using a 1/8 c0llet chuck.

Better with a collet, Degrease material with Acetone or IPA to improve grip.

How are you holding the die?

You could take a couple of thou off diameter


Thread: Dovetail cutter
15/04/2019 14:41:33
Posted by JasonB on 15/04/2019 13:35:19:
Posted by Peter F on 14/04/2019 23:20:41:

Sherwood I've found to be some of the best cutting tools available,

Just worth pointing out that Sherwood tools come from a forest in China and have never been anywhere near Nottingham, but nice to know that you find the far east product one of the bestyes

Not always, I bought a load of Carbide endmills (about 20) when they were on offer in ther flyer leaflet and they all cane in a box direct from sandvik with a delivery note with me as the drop adress.


Thread: Mini boring tool
30/03/2019 20:53:21
Posted by Douglas Johnston on 30/03/2019 19:04:00:

Seems to be only available to companies when I looked. I suppose I could try to invent a company to fill in their form but I'm sure they would show me the door.


You dont nned to be a company they will sell to anyone paying.

Even my wife has an account for getting me Christmas and Birthday presents sometimes.

Just ring up and say if you want to buy something

Its the same with MSC


30/03/2019 18:43:13
Posted by Plasma on 30/03/2019 14:28:01:

Hi Barrie,

Yes of course. I was trying to buy a Komet insert for my threading tool holder, but Komet have been absorbed by a larger group and I believe WNT is the parent group of ceratizit.

I dealt with their office in Sheffield and had to register for an account to buy anything.

The flyer included drill sets, er 32 collects etc. So might be something there for you.

Website is

Best regards Mick

The collets are very good as are the thin parting and grooving tools.


Thread: Hello, Alexander master toolmaker
21/02/2019 08:23:51
Posted by David George 1 on 21/02/2019 07:52:25:

Hi Ali Have you looked at I used one of these about 50 years ago very versatile but a pain to set up accurately.


Why were they a pain to set up.

Interested as I fancy something of that design style


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