What Did You Do Today (2017)

[Neil WyattModerator @neilwyatt]

Posted by Andrew Johnston on 15/05/2017 20:44:55:

For the first time in a good few months I've spent some of today working on my traction engines, yippee!

I've been modelling the check valves for water pump and injector, based on the castings I have. The drawings are largely nonsense. Parts don't fit, many features are not dimensioned and some things are just plain cuckoo. Here is a section of the check valve assembly so far:

I might even get to cut some metal tomorrow. Back to work on Wednesday, but I think I can get used to these four days weekends.

Andrew

How do you stop the taper plug lifting off its seat?

[MichaelRParticipant @michaelr]

Posted by Neil Wyatt on 16/05/2017 08:42:14:

Posted by Andrew Johnston on 15/05/2017 20:44:55:

For the first time in a good few months I've spent some of today working on my traction engines, yippee!

I've been modelling the check valves for water pump and injector, based on the castings I have. The drawings are largely nonsense. Parts don't fit, many features are not dimensioned and some things are just plain cuckoo. Here is a section of the check valve assembly so far:

I might even get to cut some metal tomorrow. Back to work on Wednesday, but I think I can get used to these four days weekends.

Andrew

How do you stop the taper plug lifting off its seat?

Gland Packing !!

[Clive HartlandParticipant @clivehartland94829]

Best made like a gas tap, with a washer and a nut on the bottom of the spindle.

[matt merchantParticipant @mattmerchant42413]

nice little donation for the mancave from our metrology department at work, failed calibration tests for them but still accurate enough for home workshop use, diverted from the scrap bin

Matt

[Anonymous]

Posted by Neil Wyatt on 16/05/2017 08:42:14

How do you stop the taper plug lifting off its seat?

Good question, and one I've asked on another forum. The only answer so far says to pack the gap with something suitable. I wondered if by making the sleeve longer I could use the nut, via the sleeve, to push down on the taper plug. Seems more positive to me? Everything to the left of the ball is at boiler pressure, ie, 170psi.

I even managed to cut metal for the traction engines this afternoon, first time in nearly four months. Of course being slow I only machined a surface and drilled some holes, times four. Note the slow helix drill:

The first operation to create a reference surface on a casting is always a bit of a "oh eeeer" moment. Get it right and everything that follows is sweetness and light. Get it wrong and one has to fight the misalignment every inch of the way. So worth taking the time to think it through. Especially now that I've converted the 1/4" BSP threads to 3/8" BSP there's less than 20 thou of 'spare' metal to play with on the bosses.

Andrew

[JasonBModerator @jasonb]

Posted by Clive Hartland on 16/05/2017 09:39:58:

Best made like a gas tap, with a washer and a nut on the bottom of the spindle.

But then it would not look like the original Burrell one. As MichaelR says the packing holds the spindle down into the taper, Fowlers and Savages also used the same for drain and water cocks.

Though I would suggest Andrew either makes the tapered pocked a little deeper or spindle a bit shorter so there is nothing to stop the spindle seating down into the taper

Edited By JasonB on 16/05/2017 19:33:11

[Anonymous]

Yep, thought of that; I'm going to make the taper 'reamer' a bit longer than the taper plug. Whether I alter the CAD model remains to be seen. As long as I know what's going on that's fine.

Andrew

[Neil WyattModerator @neilwyatt]

Perhaps a thick teflon washer as packing?

As an aside today I put 'Davey Arthur' into Google and it came back with a picture of Finbar Furey!

Close, but no cigar…

Neil

[David Paterson 4Participant @davidpaterson4]

Clock wheel marking jig

Mounted this on a piece of 42mm thick Jarrah so it sits on the bench.

Mind you, I have just finished my second clock before I set out to make the tool.

[Raymond Sanderson 2Participant @raymondsanderson2]

Last Thursday when moving the stuff on the patio so the termite spray could be done, I've overworked my shoulder and upper arm muscles. The right the most very little done since then in the workshop with the bench, tried a bit this morning and its going to take a while due to injury.

Took a stroll/roll down to see some Jacaranda trees which have been marked for removal by council all residence of the estate bar a few are up in arms they want them left alone. Returned via the canal/water run off path. What a beaut mornin 25C and sunshine in QLD.

[Benny AvelinParticipant @bennyavelin86238]

My alternator have been making a hell of a racket. Took it apart and found this

The black worn part is where the bearing is supposed to sit, not a very good situation. I decided to turn it down from 17 to 16 and see if it worked, but that did not clean up the damaged part. I had to go down to 15.6mm damaging the thread a bit (should be plenty strong anyways), sleeved it and turned it to target dimension.

Sleeve pressed on and turned.

I wanted to hit a j5 tolerance for an interference fit with the bearing. That is a very tight tolerance -0.002 +0.003 mm, which I hit by the way

Now the car is all silent again.

[Neil WyattModerator @neilwyatt]

Posted by Andrew Johnston on 16/05/2017 19:41:38:

Yep, thought of that; I'm going to make the taper 'reamer' a bit longer than the taper plug. Whether I alter the CAD model remains to be seen. As long as I know what's going on that's fine.

Andrew

Perhaps the barrel of the valve should be parallel?

If the packing allows a taper one to lift slightly, it will leak, a parallel one won't.

But a taper held down by a spring would be better.

[Martin KyteParticipant @martinkyte99762]

Spotted this on the 'Canal alerts system'

We are pleased to welcome The Gardner Engine Rally to Huddlesford junction on 3rd to 4th June 2017.

**LINK**

I also noticed that they have found an unexploded Bomb next to the canal at Aston, hope it doesn't blow Niel up. He lives round there somewhere I think.

regards Martin

[JasonBModerator @jasonb]

Posted by Neil Wyatt on 17/05/2017 07:19:05:

If the packing allows a taper one to lift slightly, it will leak, a parallel one won't.

On the other hand the tapered seating allows a far smaller gap than you would get between a parallel spindle and body so less chance of it leaking in the first place.

[Ian PParticipant @ianp]

Why not have the upper part of the spindle tapered so its a mirror image of the valve area? The packing would then be tapered so it both retains the stem and seals it at the same time. What Jason said applies about minimising leak points then applies to the whole stem.

Ian P

Edited By Ian Phillips on 17/05/2017 12:12:42

[MuzzerParticipant @muzzer]

Nipped out this morning to get a hacksaw from the nearby Homebase so I could hack the pinion gear off an electric motor. Instead of the traditional Eclipse-type "Junior Hacksaw", I instead opted for the "premium" model with orange frame and soft grey handle. Woo. The label says "this product MUST NOT be sold to anyone under 18". Trying to imagine why not. There is also a "caution" noting that saws by design are extremely sharp. Saves having to take it back.

To make matters more perplexing, the Eclipse model didn't have such a warning. Go figure….

Murray

[Martin KyteParticipant @martinkyte99762]

1. Is this merely a theoretical problem.

2. I thought the whole point of tapered plug valves is that they do not leak.

2b. If you are going to have a double taper why do you need the packing.

Only asking.

regards Martin

[Ian PParticipant @ianp]

Posted by Martin Kyte on 17/05/2017 12:38:01:

1. Is this merely a theoretical problem.

2. I thought the whole point of tapered plug valves is that they do not leak.

2b. If you are going to have a double taper why do you need the packing.

Only asking.

regards Martin

Good questions!

I would answer 2b by saying that creating and keeping the two female tapers in precise alignment would be a challenge. Both tapers on the stem are most likely going to be machined at one setting so are bound to be truly concentric. By having one taper made of a packing material with compressibility will allow it to conform and make the job much easier.

Ian P

[Ian PParticipant @ianp]

Martin K's point about tapered plug valves not leaking is a good one. I'm now wondering why any packing is needed.

If this valve is like the old 'gas taps' with a tapered stem crossdrilled, then there is no reason why any leak is more likely to be 'above' the cross hole than it is 'below' it. Above here refers to the larger diameter taper and below being the smaller diameter.

So if there is no leak (very close fitting taper etc), the stem does not need sealing, it just need to be retained.

Ian P

[JasonBModerator @jasonb]

The old gas isolating valves typically had a spring at the bottom to keep the tapered spindle tight in teh seating.

As MichaelR stated earlier the gland packing provides the compression (downwards) to hold the spindle down into the taper (as the spring does in a gas valve)and has the added advantage of sealing the spindle (sideways) where it exits the body.

Also allows the friction to be adjusted by how far the nut is tightened so the valve does not close due to vibration while driving along.

[MuzzerParticipant @muzzer]

The tapered valve as shown would leak and / or eject when pressure is applied without packing and a mechanical means of retention. Alternatively, to get some degree of self sealing of the taper you could insert the taper from the "big" end of the seat, with the handle emerging from the "small" end of the body and a large cover over the "big end". Of course, it might then prove hard to turn and would be quite a pain to make, which is possibly why they aren't the normal solution.

With valves, there are 2 types of leakage to control – internal (between inlet and outlet) and external (between the internal connections and the outside world. As JasonB says, I suspect that what is being described here as "packing" would be providing both a seal on the shaft and controlling the mating of the taper and its seat.

Murray

[Neil WyattModerator @neilwyatt]

Posted by Martin Kyte on 17/05/2017 10:49:04:

Spotted this on the 'Canal alerts system'

We are pleased to welcome The Gardner Engine Rally to Huddlesford junction on 3rd to 4th June 2017.

**LINK**

I also noticed that they have found an unexploded Bomb next to the canal at Aston, hope it doesn't blow Niel up. He lives round there somewhere I think.

regards Martin

Used to work in Brum for 17 years!

I've taken a cruiser along that canal!

Neil

[JourneymanParticipant @journeyman]

I was mostly writing a web page about making one of these:

It's a flip-up toolholder for screw cutting. Saw it elsewhere on the web and thought I would have a go at my own version. More details ***HERE*** for anyone who would like more info.

John

[SillyOldDufferModerator @sillyoldduffer]

Posted by Journeyman on 17/05/2017 16:21:20:

It's a flip-up toolholder for screw cutting….

John

Thanks John, that ticks one of my boxes this week. Your website's a good'un too.

[JourneymanParticipant @journeyman]

Thanks Dave, as I said not an original idea of mine but quite an interesting and useful tool. J.S. of this parish has a version that uses one of the chasers out of a Coventry die head instead of an HSS bit.

John

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