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Member postings for Redsetter

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

Thread: Bennie Railplane
20/07/2022 04:12:55
Posted by Jon Lawes on 19/07/2022 21:48:08:

According to this slightly clunky website (but obviously run by someone with infectious enthusiasm) it was the same family but not the same Person. John Bennie.


Thanks. If it was the same family, then George and John might possibly have been cousins. One source states that Bennie Lifts Ltd was founded in 1934, which postdates the Railplane, so they could not have been directly involved. You have to admire George Bennie for following his dream, however misguided it was.

None of the monorail inventors seem to have had any idea of the practicalities of railway operation, and one wonders whether any of them ever owned a model railway or even a basic train set, as it soon teaches you about line capacity, and the need for points, sidings and signalling, among other things.

There is also the fact that if you want one rail to do the work of two and carry the same load it will have to be twice as strong, so the track isn't likely to be simpler or cheaper.

19/07/2022 21:38:28

Has anyone definitely established a connection between the Bennie Railplane and Bennie Lifts? When I looked into it briefly there seemed to be no obvious connection, but perhaps someone has researched it further?

Thread: Edward Thomas. 5" gauge. Hackworth Valve Gear.
01/05/2022 16:15:16

Please don't bother with a sketch. 2x lap plus lead = hardly any in my book. I am trying to make it easy for the OP.

The opening point is the critical bit. Perhaps you can explain it better?

01/05/2022 10:04:24
Posted by Chinkoa on 01/05/2022 09:34:47:

I've just drawn out out to scale to give a 0.010" Lead I need to shorten the v/v. by 0.098 overall to 0.980 from 1.078

Do you agree?


Don't fiddle with it!

While the lead and the lap are related, i.e., you can effectively increase the lead by reducing the lap, altering the the lap will also affect the timing. The lead is a design quantity, controlled by the geometry of the valve gear. It may have been designed with no lead, so don't worry about it unless you are prepared to work through the valve gear dimensions and find out what the designer intended .

Check the opening point as said - it should be either exactly at TDC or slightly before, but not later than TDC. The valve should close at around 75 to 80 percent of the stroke. In mid gear you should get the same opening point but hardly any valve travel.

If that checks out and it is running well on air I suspect it is probably OK.


Edited By Redsetter on 01/05/2022 10:05:07

Edited By Redsetter on 01/05/2022 10:10:32

01/05/2022 09:07:03


Glad to hear you are getting somewhere. If it runs well on air it is not too far off.

Your last paragraph I'm afraid doesn't make sense as you can't measure lap or lead with the steam port 50 percent open.

Lap is the amount by which the valve overlaps the steam port with the valve in mid position - usually on the steam side so in your example with a 0.125 steam port if you had 0.125 lap the valve face would be 0.25 wide.

Lead is the amount by which the valve is open to steam with the piston at top dead centre.

With the valve length of 1 5/64, what is your opening point relative to TDC in full gear? This is easy to observe.

If there is no lead the valve will start to open at TDC. If there is 10 thou lead the valve will already be open 10 thou at TDC.





Edited By Redsetter on 01/05/2022 09:10:21

Edited By Redsetter on 01/05/2022 09:11:14

27/04/2022 09:33:03

Julian beat me to it!

There does not look to be much wrong with those figures - we could argue about the finer points all day - so I suspect the basic problem is elsewhere especially as each side is behaving differently. Are the wheels quartered properly? Slide shafts at the same angle? Both eccentric rods identical?  Axles supported in working position?

I would not have added exhaust clearance, but it may be deliberate and isn't enough to upset things.

With 0.39 valve travel the laps could be longer, so the original 1 5/64 valve dimension might be about right. If the ports are opening fully to steam, it suggests the valves are too short.

It would need all the valve gear dimensions to analyse it properly, and this is not a 5 minute job.



Edited By Redsetter on 27/04/2022 10:01:56

27/04/2022 03:00:34

Hackworth gear is not as simple as it looks, but as said, the Sweet Pea design is worth looking at and will be similar to yours.

Without knowing exactly what you have, it is hard to be specific but a few general points:

How have you arrived at the valve length? It should be the length over the steam ports plus an addition for lap at each end. The lap is typically from 75 to 100 percent of the port width. 75 percent is probably adequate in this case. The exhaust cavity in the valve should be centrally placed, and its length equal to the length over the port bars.

Are the valves positioned correctly on the spindles? They should open the ports equally (but usually not fully) at each end of their travel when the engine is in full gear, in both forwards and reverse though there may be slight variation between the directions. If you can achieve this by adjustment of the valve spindle, then the valve is not too long.

Are the return cranks correctly set? They should be at 180 degrees to the crankpin, i.e. exactly opposite.






Edited By Redsetter on 27/04/2022 03:01:18

Thread: Murad Cadet Restoration Project
03/04/2022 10:33:22

Why would you want or need a VFD anyway?

This is a gear-head lathe which gives a good range of easily changeable speeds.

And it has a single phase motor, which is not designed for use with a VFD.

Nuff sed.

Thread: First model recommendations
05/03/2022 12:07:16

The most important thing is to build something you like.

Having built a Trojan and several Stuart 10s and an S50, all using a lathe only, I think the Trojan is possibly the easiest, although there is very little in it. I built mine from scraps of plate and bar stock, and just bought the Reeves cylinder castings, and it makes a neat engine although it is quite small. The drawings are well detailed.

The 10V is perhaps slightly easier than the 10H, but the latter makes a nicer working model as the motion is more visible. The S50 arguably looks best of all when finished, but is not as simple as it appears. There is no crankshaft to worry about, but several operations may be tricky for a novice. Also the main bearing design is poor and as a result it cannot be expected to develop much power.

I would not bother with small oscillating engines. A slide valve engine has more parts, but is no harder to make and is a lot more interesting and realistic.

Thread: Concrete Panel Garage/Workshop
02/03/2022 06:37:30

It looks to me like a Compton. As said, they are no longer in business, but I think parts are still available.

Thread: Cylinder and piston sizes - help please
09/02/2022 13:05:10

I take it this is the incomplete engine in your other post?

If both cylinders are to be the same bore, it is not really a compound.

For 1/2 inch bore the piston length could perhaps be anything from 1/4 to 1/2 or a bit longer, depending on how you intend to seal it - for a low working pressure you could make it long, and just put some oil grooves in.

Clearances are not going to be critical on something like that - aim for 1/32 each end, but 1/16 will not hurt.

Since you have the original valve gear, I would work out the valve travel and port face dimensions alongside designing the cylinder, and this should give you a few clues to the original proportions.

Mill engines usually had quite long cylinders, and bear in mind the rear cover needs to be fairly long to accommodate the gland.

It looks quite lightly built, so do not try and extract too much power from it!

Just my opinion.

Thread: Need to cut long thin strips of steel (& plastic) - e.g. with an angle grinder?
18/01/2022 18:24:21

Just order your materials cut to size.

Thread: 5" Gauge Loco Project
16/01/2022 21:39:40

Bear in mind that 5 inch gauge locos are heavy and a Simplex or a Sweet Pea is a 2 person lift. Don't neglect the smaller and simpler designs - Rail Motor, Scamp, or Dougal come to mind. And think whether you want something for serious passenger hauling, or just a little engine to play trains with.

Thread: Stephensons valve gear
28/11/2021 20:25:24

A locomotive type link has the eccentric rod pivots on (or about) the curved centre line of the link and beyond the ends of the slot in which the die block fits. A launch type link (which is not the same as a true launch link) has the eccentric rod pivots to the rear of the link, behind the slot. Both type have pros and cons but the main advantage of a launch type link when used in a locomotive is is that the eccentrics will be smaller for a given valve travel.

There is, unfortunately, a lot more to it than that.

Thread: ML10 Headstock mounts
17/10/2021 07:09:24
Posted by Engine Builder on 16/10/2021 20:03:31:

You could easily make a replacement, you have one to copy.

I totally agree. It's just a bit of flat bar basically, and not all of the dimensions are critical. A good first project!

Thread: joy valve gear (Derby 4f)
12/09/2021 10:06:40

OP- Removing the anchor link effectively disconnects the valve gear, so I am not sure that proves anything. Does the valve/valve spindle move freely over its designed travel?

Thread: I need to cut chamfers into x64 pieces of mild steel - any advice?
06/09/2021 20:27:37

OP, people on here are doing their best to advise you.

Several useful ideas have been suggested. Without knowing more about the design, or the purpose of the parts, it is difficult to be more constructive. It does seem that in your circumstances it would be best to outsource the job, then you can move on to the next stage of your project. It is not clear why you won't do so.

We are a helpful bunch by nature, but we all have busy lives and projects of our own. Please don't waste our time.

Thread: Electric motor speed
04/09/2021 22:07:15
Posted by KEITH BEAUMONT on 04/09/2021 21:52:30:


I did say it was a Brushed motor/


In what way does a Universal motor differ from a brushed mains type?


Yes I heard you the first time that is why I replied as I did! A universal motor is another name for a brushed mains motor. An induction motor is a totally different thing.

04/09/2021 21:41:01

Put simply, if it is an induction motor the speed depends on the mains frequency and the number of poles, but a brushed motor does not work that way.

Thread: Replacing a bushing
03/09/2021 07:02:30

Quite possibly an Imperial size, as posted above. There is still a lot of Imperial stuff in use, even in new machinery. I would suggest going to a bearing factor with a trade counter, who can measure it properly and will know the market, rather than trying to do it on line.

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