Member postings for Redsetter

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

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.

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.

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

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.

Just order your materials cut to size.

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.

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.

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

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?

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.

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.

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.

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.

For those interested - required reading on the Leader Class starts with a good general account in "Bulleid - Last Giant of Steam" by Sean Day-Lewis, a very readable biography. More information, and perhaps more technical detail in "Bulleid of the Southern" by H.A.V. Bulleid, the great man's son and also an engineer.

Then there are several editions of Kevin Robertson's "Leader - Steam's Last Chance" which is a comprehensive account with many interesting photos, especially of the construction phase. Robertson's research is very good but perhaps understandably, he does not have the technical knowledge to analyse the subject in depth. .

See also - "Bulleid and the Turf Burner" by Ernie Shepherd which details the "Irish Leader" which is a subject in itself, and seems to have worked rather better.

I have just had a trawl through youtube and it seems the video is unavailable. Possibly the Bulleid Society may have access to it? I'd like to see it again.

Yes, there is a short film which was available on youtube fairly recently. No idea whether it is still there, but it is absolutely fascinating and well worth searching for.

OP- Your work on this lathe so far has been first class, but I think you should just make a few things on it, see how they turn out, and learn to use the tools before you worry too much about the bearings.

I don't think Oilite bearings are appropriate. The lathe is not designed for them. They are not meant to fit in split housings, and you are not supposed to scrape or ream them - or split them - to fit.

The Oilite bearing in your link has an OD of 1 5/8", so 3/16" wall thickness. Your existing bearings look thicker than that. Even if you find one which will fit straight in, it is unlikely to be much more accurate than what you have already, given the wear on the spindle.

Realistically, you do not yet have the skills or equipment (i.e. another very accurate lathe) to machine new bearings from scratch, so stick with what you have.

If your measurement of 10 thou play is accurate, then the bearings can probably be nipped up to reduce that. They have probably never been adjusted before, and the bearing caps look a lot stronger than on many lathes of that era, so you will very likely get away with a fraction of a turn on each clamp screw. It won't need much.

Just my opinion.

Edited By Redsetter on 02/08/2021 16:18:34

The countershaft looks very practical, and you will probably think of refinements as you go along.

The 56 to 618 speed range is probably the more useful of the two options but it is not super-critical and depends a bit what work you are doing. With the 84 to 841 range you may find that you have to change into back gear rather often in normal use, which is a nuisance. It should be possible to get a wider range with different pulleys, e.g. ML10 has 280-490-840 in direct drive, and 48-85-145 in back gear. But see how you get on.

Yes, you can crack the headstock bearing castings if you overtighten them, so you are right to be cautious, and the bearings themselves don't look too bad so I would leave them alone for now - there is no guarantee that current standard sizes will fit. If it ain't broke don't fix it, and the main thing is to get it all working at this stage.

Good work on the cross slide.  It is worth adding some sort of dial if you can, so that you know where the cut has got to.  The tailstock clamp again looks fine to start with, perhaps an improvement would be a captive stud as it is convenient to be able to adjust it with one spanner.

Edited By Redsetter on 22/07/2021 19:06:18

Edited By Redsetter on 22/07/2021 19:15:41

Frankly, I don't think they are worth the trouble on a small lathe in intermittent use. They are just a distraction from making things, and you have to remember to turn them off when you finish. I have had two plain-bearing lathes with simple oil cups with wick feeds, and it is no bother to top these up with an oilcan as required.