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Member postings for Michael Gilligan

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

Thread: 5BA Threads
29/09/2020 17:33:19
Posted by Mike Donnerstag on 29/09/2020 09:38:21:

Michael Gilligan: I haven't used Elcoda, though I do use Paulus Bowparts who are also in Germany. Although they don't make the BA thread bow screws (reduced to 3mm) as used by the Hills workshop, they do the '3mm Inch Thread' bow screws, which are a reduced 5-40 UNC thread, as in the photo below:

[…]

I have made these screws myself using a 5-40 die, closed down to give a nominal diameter of 3mm. However, like the 5BA bow screws, it seems I will need to make a custom tap in order to tap the thread on the brass eyelets.

 

.

Thanks for the additional information, Mike

You obviously know your subject much better than I ever will ... but I am still a little bewildered.

Are these threads really produced with a closed-down 5-40 die, or are they perhaps a truncated thread-form ?
.

If you have a commercially produced one available, I would be happy to photograph it for our mutual education.

MichaelG.

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Edit: The two lines for 5-40 on this chart make interesting reading

https://www.engineersedge.com/screw_threads_chart.htm

Edited By Michael Gilligan on 29/09/2020 17:41:01

29/09/2020 17:15:09
Posted by norm norton on 29/09/2020 09:19:49:

.

Very noble of you, Norm yes

MichaelG.

Thread: Cheap Milling Vice Question
29/09/2020 08:15:10
Posted by Blue Heeler on 29/09/2020 04:20:18:
Posted by Pero on 29/09/2020 04:18:53:

Presumably not Chain of Custody or even Commander in Chief.

Ahh. So many acronyms, so few letters in the alphabet!

Something to do with protecting the commercial advertisers I believe.

I'm sure one of the Mods will explain all shortly.

Pero

Thanks Pero

.

Or you could just click the hyperlinked words Code of Conduct ... on this very page

on the line immediately above the (Add Posting) button

MichaelG.

angel

Thread: Quality Problems With the Sieg sx2.7
29/09/2020 08:06:43
Posted by Nir Somthing on 29/09/2020 07:21:43:

[…]

In terms of what I want to build, my first project is to finally finish a CNC machine out of Aluminum (or from polypropylene and then cnc the Aluminum). when I built the model, many times I had two different parts with holes and I hoped that they will match but they didn’t, so I always had to choose a few holes and widen them up. I used a DRO and an edge finder and the deviations came from the press drill quill which has an enormous play.

[…]

.

May I suggest a very simple practical test ?

Take two thick strips of of your Aluminium alloy and clamp or glue them face-to-face

Now drill through the pair at two locations

Separate them, and de-burr if necessary

Turn the top strip over, and try passing a couple of close-fitting rods through the assemblage.

If all is well, you can proceed to doing something similar, but with four holes on a square grid.

The two plates should then match in eight pairings [four positions, and two ways up]

If you find any errors ... investigate.

MichaelG.

Thread: 5BA Threads
28/09/2020 20:36:23
Posted by norm norton on 28/09/2020 18:34:14:

.

What people are failing to acknowledge is ...

.

So presumably I am not included in ‘people’ angel

MichaelG.

Thread: ER 32 Collet Tightening Torque.
28/09/2020 20:29:07
Posted by JasonB on 28/09/2020 18:28:55:

Michael, have you tried Nominal size only ER Collets rather than collapsible oneswink

.

No ... but presumably that would not require the high torque that collapsing by a millimetre would.

[ and therefore would not be particularly relevant to the OP’s question ]

MichaelG.

28/09/2020 17:53:13
Posted by J BENNETT 1 on 28/09/2020 17:34:25:

Recently, looking at ER 32 nuts with a ball bearing to reduce friction and increase clamping force (ARC and others sell them) got me thinking about how much torque should be applied when tightening an ER 32 collet.

[…]

Anyone care to give comment?

.

The numbers look valid ... so the problem is real

That’s one of the reasons why some of us still prefer traditional ‘fixed size’ collets

MichaelG.

Thread: Quality Problems With the Sieg sx2.7
28/09/2020 14:19:38
Posted by Tony Pratt 1 on 28/09/2020 10:35:58:

... the chuck/collet or whatever is only really connecting the DTI to the spindle bearings in a rigid set up ...

.

I apologise, Tony ... You were correct in your first assertion.

I have just returned from a good long walk, and some pondering; and it became quite clear that the mis-aligned chuck would simply form part of the “any shape you like, provided it’s stiff enough” trammel beam.

By way of demonstration : here is the scrappy little sketch that I doodled whilst I was out.

.

0f6ae261-720a-40d9-99ee-02af2dea90ba.jpeg

.

blush MichaelG.

28/09/2020 10:20:47
Posted by Tony Pratt 1 on 28/09/2020 09:59:32:

Chris, I totally disagree, whatever holding method is used will present the DTI probe in the same relative position to the table as long as the set up is rigid […]

.

Sorry, Tony ...

It’s simple trigonometry : If there is an angular error between the ‘output axis’ of the chuck and the axis of the machine spindle, then your trammel beam will act like a swash plate and the DTI will rise and fall.

MichaelG.

.

Edit: Swash Plate animation: https://youtu.be/z-wA9Tx8930

Edited By Michael Gilligan on 28/09/2020 10:23:21

28/09/2020 08:52:48
Posted by Tony Pratt 1 on 28/09/2020 08:26:33:

Steve, if you understand tramming you will realise it doesn't matter how the swing rod is held [chuck/collet etc.etc] as long as the set up is rigid & the DTI used is repeatable the results will be reliable.

Tony

.

That should start an interesting discussion angel

MichaelG.

.

Edit: and I see it already has

Edited By Michael Gilligan on 28/09/2020 08:54:08

Thread: Removing bang in self tappers
28/09/2020 07:55:33

Chas

I have no idea whether this is a definitive list, but it looks a useful place to start: **LINK**

https://www.rivetsonline.com/drive-screws#1

I remember, when my dad worked for GKN in the early 1960s, there was a wide variety available.

MichaelG.

Thread: 5BA Threads
28/09/2020 01:20:55
Posted by Mike Donnerstag on 27/09/2020 23:21:07:

Having done considerable investigation and experimentation, I found that many threads used for instrument bow screws were in fact modified by over-tightening the die to reduce the major diameter from 3.2mm to 3mm. This was true of the 5BA screws and the 5-40 UNC ‘Inch thread’ screws and means that the standard tap is too large.

[…]

.

This is all rather bewildering, Mike

In trying to ‘catch up’ ... I have just found this page: **LINK**

https://elcoda.com/bow-screw-250938.html?language_code=en

... which seems to present another ‘variation on the theme’

[quote]

Bow Screw with Rolled Inch Thread, Bronze Eyelets, Violin, Viola, Cello
These bow screws are finely-crafted in the style of the great French bow makers.The rolled thread allows the thread portion of the screw to have a larger diameter than the shaft portion.
Violin,Viola - dimensions 74 mm, thread 1,8", shaft diameter 2,7 mm.
Cello - dimensions 80 mm, thread 9,64", shaft diameter 3,0 mm

[/quote]

Can you provide any close-up photos of typical specimens of what you are working with, please ?

MichaelG.

.

P.S. There are crucial differences between the BA and Unified thread forms, so I think this merits serious further investigation.

27/09/2020 08:47:54
Posted by Bob Stevenson on 24/09/2020 22:31:14:

As a youngster I was told that BA threads were outmoded and "archaic" and […]

fine metric does not, in practice, turn out to have the same facility or 'feel' in the work.

.

Presumably told by someone who didn’t appreciate the sophistication of the thread-form

Blessed are the ‘Bean-Counters” ... ?

MichaelG.

Thread: Warco Rotary Table - Can anybody give feedback please?
27/09/2020 08:38:25
Posted by not done it yet on 27/09/2020 08:03:37:

Yes, the whinge should’ve been put on another thread, not a continuation of a previous thread?

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Au contraire ... I see the ‘whinge’ as a direct and relevant response to the opening question.

MichaelG.

Thread: CLASSIC MOTORS DE DION
26/09/2020 18:49:45
Posted by ega on 26/09/2020 18:32:15:

Would you rate DeepL over Google Translate?

.

Personally, yes ... especially with German to English

... and I find the interface convenient.

MichaelG.

Thread: New Haven movement; Questions from a beginner
26/09/2020 15:14:35
Posted by Speedy Builder5 on 26/09/2020 13:57:11:

[…] search Cucko clock Calibration or similar.

.

For 99p that had to be worth a bash : **LINK**

https://apps.apple.com/gb/app/cuckoo-clock-calibration/id1171487289

... even if the developer does claim/admit :

Turn your iPhone into a precise train count sensor with an unbelievable 0.01 milliseconds accuracy!!

on his website ... and 0.001 milliseconds on the AppStore dont know

MichaelG.

Thread: Unusual Project
26/09/2020 12:41:29

Posted by Neil Wyatt on 09/09/2020 19:54:26:

[…]

Here's the current state of play (I haven't added the far wing as I'm just mirroring eh parts in Cura).

.

^^^

MichaelG

Thread: Macrome tools
26/09/2020 12:07:07

Strangely enough ... Espacenet found this patent when I searched for ‘Macrome’ : **LINK**

https://worldwide.espacenet.com/patent/search/family/009819914/publication/GB753221A?q=macrome

... the Macrome process gets a mention in the closing paragraph

MichaelG

Thread: CLASSIC MOTORS DE DION
26/09/2020 11:55:56

Until someone comes up trumps ... try DeepL : **LINK**

https://www.deepl.com/translate

MichaelG.

Thread: [Project 3] Dickson T1 Tool Holder
26/09/2020 08:09:13
Posted by JasonB on 24/05/2020 19:26:47:

.

A few suggested a shaper for these types of jobs, this popped up on my Youtube today which you may enjoy.

.

Missed that, yesterday, Jason

The opening ‘titles’ are sheer joy ...

I shall watch it with due reverence, later.

MichaelG.

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