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Member postings for Swarf, Mostly!

Here is a list of all the postings Swarf, Mostly! has made in our forums. Click on a thread name to jump to the thread.

Thread: Workshop temperature - cold
29/11/2020 16:39:48

Hi there, all,

Thermal comfort is a complex subject. Even if the air temperature is warm, you can still feel cold if the walls are cold. The body is sensitive to transfer of radiant heat as well as to conducted heat.

Fortunately, it isn't necessary for ALL the walls to be warm - you just need enough warm wall area for the radiant gain to balance or exceed the radiant loss. That's why those infrared bathroom heaters with the spiral element inside a quartz tube (preferably backed by a gold-plated reflector) were effective.

I guess it helps if there is some warm surface both aft as well as fore - otherwise you could be warm in front but chilly behind! (Am I allowed to write 'behind'?? ) Thinking a bit more about that, I guess a radiant heat source will raise the temperature of the other walls faster than will heat conveyed by the warm air?

And I guess the radiant heat source doesn't have to be wall - one of those free-standing oil-filled radiators works for me.

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 29/11/2020 16:41:49

Thread: What am I?
25/11/2020 09:21:48

Hi there, all,

Either Rolls or Royce (not the financial partner) denied being an 'engineer' - he claimed to be a 'mechanic'.

By the way, I think that in the UK it's an 'Institution' not an 'Institute'. If that matters.

And don't get me going about non-technical managers preferring the advice of an inexperienced colleague with a degree over mine based on lots of experience plus a degree-less C.Eng.!

Best regards,

Swarf, Mostly!

P.S.: Eventually B.Sc. (Hons) Open!!!!!!!

Thread: Ball ended handle - how to
22/11/2020 20:42:06

Hi there, all,

I thought I'd better have another search and, this time I found the thread. It's on the Mad Modders web-site, here:

Skiving Tool

The thread is dated 2014. The problem is that the videos are all unavailable. He showed the process in use for a three-ball handle as well as the tear-drop type. (So my previous post wasn't all that off-topic after all! )

If anyone is interested in the process, there are some still photos there that are interesting.

Best regards,

Swarf, Mostly!

22/11/2020 17:39:38

Hi there, all,

I hope I may be forgiven for a slightly off-topic post. Well, it is to do with handles.

In the background of Evan Lewis' post you can see what I describe as a 'tear-drop handle'. Somewhere on the Internet there is a video of one of these being turned using a form tool so arranged that only part of the tool is in contact at any time. If I remember correctly, the top-slide (aka 'compound' ) is set at a slight angle to the cross-slide and is mechanically driven. Again if I remember correctly, the technique is named as 'skiving' (until I found this video I thought that was the process for producing a thin sheet of leather, such as is used to surface a bureau writing flap) .

I found this video fascinating but my recent searches for it have been unsuccessful!!!

Maybe one of the members here is familiar with either the video or the machining technique or both?

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 22/11/2020 17:40:22

Thread: Cutting copper tube square
13/11/2020 16:21:10

A common method with cutting plastic pipes, e.g. underground waste pipes, is to wrap a piece of paper around the pipe so that the edge lines up where the paper overlaps. On your 54 mm copper the same method would probably work. Once positioned, hold the paper from moving and go over the edge all round with a Sharpie. Then remove the paper and cut at the edge of the Sharpie mark. I reckon the result would be accurate enough, assuming that you're going to fit an end disk with a soft or hard soldered joint.

If it had to be a lathe job, the fixed steady rest could help but I'd regard cutting thin copper tube with a parting tool as quite an adventure!!!!!!!! Filling the tube with a wooden bung (or maybe even Plaster of Paris) sounds like a good idea.

When you've done the job, please come back and show us a few photos of the result.

Best regards,

Swarf, Mostly!

Thread: Temperature control when grinding HSS tool-blanks?
15/10/2020 11:55:56
Posted by Peter G. Shaw on 14/10/2020 17:10:55:

One thing that I have noticed is that when grinding using the coarse wheel, the tool doesn't seem to get as hot so longer hand held grinds are possible. But the finger temperature test still stands even for that.

One other thing, and this may be only applicable to me. The motor on my grinder, a 150W Clarke something or other with 5 inch x 1.2inch wheels, gets very hot itself, so much so that after a modicum of grinding, I have to leave it to allow the grinder to cool down. It's been like it for over 30 years and is still going strong (famous last words!) so I assume it's being used within its design parameters. Anyway, there's another reason for short bursts of grinding.

Peter G. Shaw

Hi there, Peter,

I have a modern two-wheel grinder that actually specifies a duty cycle on the motor rating-plate.

Best regards,

Swarf, Mostly!

Thread: Brass Founder vs Brass Caster
14/10/2020 16:12:34

The French verb meaning 'to melt' is 'fondre'.

However did Kelly's Directory manage before the Norman Conquest? smiley smiley smiley

Best regards,

Swarf, Mostly!

Thread: Temperature control when grinding HSS tool-blanks?
14/10/2020 16:06:51

Jason,

Oops, I'm sorry to have started a thread so close in topic to the one to which you linked. In my own defence, the title of that other thread is not exactly an intuitive search string.

In my opening post, I should have made it clear that I was concerned with grinding a new tool blank - not merely touching up a tool that was already at the right shape.

Best regards,

Swarf, Mostly!

14/10/2020 13:20:15

Hi there, all,

I've noticed that, when grinding an HSS tool-blank, some folks cool the blank at intervals by plunging it into cold water. (I'm trying to avoid use of the term 'quenching'. ) On the other hand, I've heard it said that such plunging of HSS blanks leads to micro-cracks at the tool cutting edge.

Please can any knowledgeable members here give us a metallurgist's comment on this proposition? And what is the experience of the general membership?

Some 'real' workshop tool grinders or their pedestals have water-pots built-in - is this a historical legacy from pre-HSS days when tools being ground would have been carbon steel?

Best regards,

Swarf, Mostly!

Thread: ML7 tooling
13/10/2020 16:04:10

I hope this helps:

 

scan0002.jpg

 

The uppermost item is the four-way tool-post.

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 13/10/2020 16:05:32

Thread: Grumpy old men
12/10/2020 09:08:03
Posted by ChrisH on 11/10/2020 22:13:14:

SNIP

An hotel instead of a hotel, after you only use 'an' if the object it refers to starts with a vowel. And so on.....

SNIP

Chris

Edited By ChrisH on 11/10/2020 22:16:00

Edited By ChrisH on 11/10/2020 22:16:47

Chris,

Believe it or not, the rule is 'a vowel or aitch'!

My wife has amended her criterion from 'see' to 'put your hands in the water'.

Best regards,

Swarf, Mostly!

11/10/2020 20:37:49
Posted by Mike Poole on 11/10/2020 17:08:22:
Posted by Swarf, Mostly! on 11/10/2020 16:26:22:
Posted by Brian Baker 1 on 11/10/2020 16:19:00:

"Boat" instead of "Ship"

My wife's definition: you're on a boat if you can see the water both sides at the same time without moving!

Best regards,

Swarf, Mostly!

I believe a submarine is a boat, I would not like your wife’s definition to apply to this onesmiley

Mike

Mike,

I agree that a submarine is a boat. However, the nearest my wife gets to a submarine is when she plays 'Silent Hunter'. So a real submarine is sufficiently remote from her everyday experience for her to disregard submarines when formulating her definitions of boats vs ships.

Best regards,

Swarf, Mostly!

11/10/2020 16:26:22
Posted by Brian Baker 1 on 11/10/2020 16:19:00:

"Boat" instead of "Ship"

My wife's definition: you're on a boat if you can see the water both sides at the same time without moving!

Best regards,

Swarf, Mostly!

Thread: Please Avoid Political and Partisan Issues
02/10/2020 15:48:17
Posted by Ian Johnson 1 on 02/10/2020 13:57:12:

How to start a fight in a pub? Just start a conversation about religion or politics!

I'm glad the moderators are looking out for this political nonsense

IanJ

Hi there, Ian,

Maybe you should have included football?!?! smiley smiley smiley smiley smiley smiley

Best regards,

Swarf, Mostly!

Thread: Hydrogen-powered train makes UK maiden journey
30/09/2020 10:02:17

Here's an interesting read:

Hydrogen

Best regards,

Swarf, Mostly!

Thread: Change gear alternative material
10/09/2020 17:51:31

Hi there, Paul,

First of all, it's 'Tufnol', not 'Tufnell' which I think is a district of London. smiley smiley smiley

I suggest that a surf through **LINK** would be a good way to spend a half-hour or so.

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 10/09/2020 17:51:57

Thread: Painting on old galvanize
05/08/2020 10:41:36

Hi there, all,

I don't know what process is used for the galvanised sheet steel from which garage doors etc are made. Maybe it's an electro-zinc process.

I doubt that it's a hot dip process unless it is configured rather in the shape of a float glass plant.  (Long and narrow and hot in the middle! )

The following is my understanding about hot-dip galvanising - I welcome correction from any members with first-hand experience. I understand that hot-dip galvanisers float a thin layer of molten palm oil on the surface of their molten zinc vat/bath. When the item is removed from the bath it gets coated with a film of palm oil on top of the zinc - it is this that makes the item difficult to paint until the weather and any passing microbes have removed it.

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 05/08/2020 10:43:00

Thread: Today's delivery
29/07/2020 16:31:52
Posted by Henry Brown on 29/07/2020 14:15:26:

I had this 200mm grinding wheel come from Cromwells yesterday. I was somewhat alarmed at how it was able to bump about in the box as the air bags weren't doing much.. The wheel rings ok so all's well but I'd expected better from Cromwell, I chose to buy from them but the local store but no stock of this wheel so had to go on-line.

20200729_140131.jpg

Hi there, Henry,

Sorry if this is off-topic.

I was told by the guy in my local branch of Cromwell's that I'd have to buy grinding wheels via their web-site - they didn't stock ANY grinding wheels in the shop because they have a shelf life?!?!

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 29/07/2020 16:32:37

Thread: DTI accessory threads - Mercer - Verdict etc.
19/07/2020 18:58:34

Hi there, Rik,

I don't know if it's in the latest edition but the MSC catalogue used to have a couple of pages devoted to screw-on accessories for DTIs. There were two series, one with a metric thread, the other with a USA inch-based thread. (The listing says what the threads are. )

I haven't checked lately but you might find their on-line catalogue still lists that information.

Best regards,

Swarf, Mostly!

Thread: Fiber change gears
17/07/2020 12:05:35
Posted by Circlip on 17/07/2020 11:41:31:

Nylon absorbs water and even the "Low" absobtion rated Nylon 6 or 6-6 does to a lesser extent. Tufnol should not be lubricated, it's a layered material.

Regards Ian.

Hi there, Ian,

Are you suggesting possible delamination?

Best regards,

Swarf, Mostly!

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