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Member postings for Stub Mandrel

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

Thread: To dump or de-rust?
23/01/2014 17:58:17

I understand that with electrolysis and phosphoric acid they convert the rust to compounds with similar dimensions to the original steel, whilst acids just remove the rust. Which you choose will depend on the degree of pitting that is acceptable. I have restored morse tapers to an acceptable finish with electrolysis followed by oiling.


Thread: Silver steel expanding on hardening
23/01/2014 09:55:29

I would try Paul's suggestion first, if you haven't already tempered the broaches. They will snap on first use if you don't anyway.

if they still don't fit,. isn't it easier to take a skim off the inside of the holder?


Thread: Hirth Couplings
22/01/2014 17:03:54



Looks like there are no standards... "Hirth joints are designed as mating pairs and, unlike splines, there is no standardised off-the-shelf sizing system for them."


Thread: Ally Pally show
22/01/2014 17:01:02

Aside from state subsidised museums and some of the very small visitor attractions there aren't many days out for £30 a head these days, including the travel.


Thread: Hick & Son Crank Overhead Engine
22/01/2014 16:57:22

Good suggestions, but I don't think I have ever got as far as five


Thread: Long Term Planning for a Workshop Size
22/01/2014 16:52:00

The high temperature (bluey white) LEDs are great for kitchens and areas you want to feel clean and fresh. they do wonders for our compared to halogen GU10s. Having seen two LED GU10s and 2 halogen GU10s in a 4-place fitting, 4W LEDS are brighter than 35W halogen - but less directional - so the halogen look brighter if you 'stare into the beam'.

The lower colour temperature (warm white) LEDs are ideal for bedrooms and living rooms you want to be 'cosy'.

I'm still debating the ideal type for a bathroom with Mrs Mandrel.

Those who want a particular colour might note that there are adjustable colour ones that smartphone users can tweek from anywhere in the world...


Thread: Ally Pally show
22/01/2014 13:23:49

> Bingley Hall in Birmingham

Having worked in Brum for nearly 18 years this confused me a bit - the only Bingley Hall I have been to was in Stafford (google tells me it was 2 May 1982!). Wikipedia tells me the Birmingham Bingley Hall was the first purpose-built exhibition hall in the UK (1850) and helpfully shows a picture of the hall demolished so it could be built! Apparently it burnt down in 1984.

As to the future of shows, what's needed is plenty of ideas for ways to make them pay for all concerned. ..



>edit - got Mr Bradford & Mr Bingley on the Brain!<

Edited By Stub Mandrel on 22/01/2014 13:26:53

Edited By Stub Mandrel on 22/01/2014 13:29:12

Thread: 3.5" guage society
21/01/2014 20:33:40

The original threads are here:


also here:


The website offering free membership is here:


I tried to register as a free member but it still directed my to Paypal so I aborted.

The registration page says I'm already a member and won't let me register. The login page says it can't find my details.

It's not clear if the attempt to set up a society was a commercial venture or not.

I still think it's a gap needing to be filled, perhaps there is a need to set up a forum to discuss and agree what they will actually do and how they will operate?


Thread: Indentfication of Induction Motor
21/01/2014 19:56:05

> Problem with end cap. Can it be fixed?

The damage appears cosmetic, so JB Weld or any other epoxy putty should do the job.


Thread: Hick & Son Crank Overhead Engine
21/01/2014 19:33:31

Piercing saw! I can't get one of those blades to last more than a few strokes... just plain ham fisted.


Thread: forming a thread on piano wire
21/01/2014 19:25:49

Hi Warwick,

Welcome aboard - the big question is - can you tell us more about your motorbike?


Thread: Indentfication of Induction Motor
21/01/2014 19:09:20

Bearing in mind a recent incident reported here, check if that any insulation on internal connecting wires hasn't broken down. If it has, replace with modern wire of the same cross-section.


Thread: MT v R8
21/01/2014 19:06:50

The tightening torque seems to be very dependent on the type of nut. I use a C-spanner with slotted nuts and a tommy bar in the chuck.

To hold cutters with shanks of around 10-13mm and plain nuts I found I had to apply plenty of force.

Since changing to ball bearing nuts I find ER25 easy to get nice and secure with much less force. The release force is never more than wrapping my hand around both tommy bar and spanner and squeezing hard.


Thread: Softening a hardened tool holder
21/01/2014 17:55:53

What modification do you nee to make? is it to reduce height or bore out the fixing hole?


Thread: Nemet - Lynx
20/01/2014 20:42:57

> all the systems rely on the the hall switch being on the crankshaft,

Designed for 2-strokes?


Thread: 12 volt motor
20/01/2014 20:11:25

The original question was the wiring.

Assuming a 12V or similar motor, you need a 2-pole changeover also known as a 2-pole double throw switch (2PDT).

This has six terminals, typically arranged as two rows of three:

1 2 3

4 5 6

A quick check with a multimeter (or a battery, bulb and bit of wire) will show that he effect of the switch is to short the middle pins (2 and 5) to either 1 & 4 or 3 & 6, depending on the direction of the switch toggle.

Connect battery + to 2 and battery - to 5

Connect one side of the motor to 1 and 6

Connect the other side of the motor to 3 and 4

The switch will now act to reverse the motor

An on/off switch in one of the battery leads will provide your on/off facility

If you want a limit switch to stop the motor at each end of its run the then fit one of these between 1 and the motor and the other between 6 and the motor.

Test the limit switches,and if the motor stops when heading away from them reverse the battery connections.



Thread: sun/planet gears
20/01/2014 19:42:42

Brians formula is correct. I'm not sure how you design the cutter profile, however. I do know that you will have to plane the ring gears unless they are very big.

If it helps, the general principle is to design gears just by drawing the pitch circles (each of which should have a diameter of number of teeth/DP. If designing with a compass or moving circles around in a cad program the pitch circles should be set out so they touch each other with no gaps or overlaps. If doing it the 'scientific way' the centre distance between gears is (teeth in gear 1 + teeth in gear 2)/(2 x DP).

For sun and planet gears inside an internal ring gear, the PCD of the ring gear is:

PCD ring gear = PCD sun gear + 2*PCD planet gear = (teeth in sun gear + 2*teeth in planet gear)/DP

My head hurts now...


Thread: Brass Studding
20/01/2014 19:32:19

in brass its a size that's nice and easy to screwcut as well.


Thread: Long Term Planning for a Workshop Size
20/01/2014 19:29:34

Flywheel size is the limiting factor. I once told Anthony Mount that I'd like to make some of his designs but my favourites all had 8" flywheels a little too big for my lathe! They fit in the gap on a Myford series 7.

You should be able to turn a 7" Victoria flywheel on a standard mini-lathe (7 1/2" swing), although you will have to use a little thought when Mounting the tool in the toolpost. The trick is to mount a left hand knife tool lengthwise in the back of the four-way toolpost. There's also a simple mod to get 1/2" or more of extra travel I can detail if it helps.

An X2 mill is more than big enough to machine the bedplate, but there's no reason why you can't do this by hand techniques if you have the skills and patience.

I find a pillar drill invaluable - because it is ready (and therefore used) all the time. Changing tooling on a mill is a bind so I try to keep an ER25 collet chuck in as much of the time as possible.


Thread: Looking for an acid supplier
20/01/2014 19:16:49

> Hi Mick, I have over a hundred trees in my garden ....

I've seen over 100 trees in a square metre - they were sycamore seedlings!


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