Sanderson Beam Engine

I purchased a set of castings (in CI) for the above engine from Clarkson's in 1980 and have been working on them on and off (mostly off!). I'm at the stage of making the links for the parallel motion and I recall reading, I believe in ME letters column (mid 80s?), a comment that the dimensions on the plans were wrong. I have since been unable to find it. Does any one know of it? Has anyone completed the model and can comment on whether there is a problem with the dimensions?

The dimensions on my set of plans are: 2 off each of 2 31/32", 1 3/16", and 5/8".

I can't spot anything in the indexes of articles. May be worth looking through Stan Bray's build in 1999 , 4101 covers the parallel motion.

Also contacting Blackgates who now sell the engine to see if they have anything different on their drawings.

J

I also have gone through all the indexes with no luck. I have read through Stan Bray's build, but it is only pictures, no drawings..(copyright?) If I get no other responses I'll try Blackgates. Thanks

John,

I've got the Blackgates drawings. I can't access them until Sunday but I'll let you know then what the dimensions are.

Rod

Rod

Thanks, that would be great.

John

John,

I have built the Sanderson Beam Engine and the parallel linkage dimensions were kept as the original Clarkson drawing. However, check the beam casting bosses on both sides of the beam to make sure that holes you are going to put in them are at the same centres as the horizontal rods of the parallel linkage. It would look really bad if the holes were not central to the bosses. If the bosses are slightly out due to a bad pattern then either machine the bosses to reposition them slightly or adjust the horizontal rods to suit. The important thing to remember when erecting the engine is that when the beam is horizontal, the crank should be horizontal and at that point the parallel linkage prescribes a right angled parallelogram. The short links to the parallel linkage support bracket are also horizontal at that time. To achieve those conditions you may need to shim one or more of the crankshaft bearings, the column height and the parallel linkage support bracket face. I took photos of all the main machining set ups for this engine and also the erection of the engine. If you get in touch I can send you copies on a CD if they would be of interest.

Geoff

Geoff

Thanks for your reply. Your description of the geometry of the parallel motion confirms what I had come up with from studying the drawings. So that's good! When I laid-out the holes to be drilled and reamed in my beam I found that using the plan dimensions they didn't come in the centre of the bosses (I don't like the look of that) so I adjusted them to be centred in the bosses, keeping the distance from the beam pivot to the hole at each end equal. The new dimension from the piston rod hole to the one for the the parallel motion linkage turned out to be 3.023" vice 2 31/32" so I assumed that the length of the long link would have to match, otherwise we wouldn't have a parallelogram. Your description confirms my assessment, Thanks. I wonder if that comment in ME came about because, the author, when he built the engine centred the holes in the beam bosses but didn't adjust the length of the link to match?

John

John,

On full sized beam engines the length of the horizontal links are usually set at one half of the distance from the piston rod hole to the beam pivot. The horizontal links have to be that length or the geometry doesn't work, so you did the right thing in setting the distance at 3.023. Curiously, on my set of drawings which are Harry Clarkson's original issue of October 1969, the horizontal links are 3 1/32 ins. long which is close to your new length. (the vertical links on my drawing are 1 3/16 ins. and the short anchor links are 19/32 ins.). It is perhaps obvious but another measurement to adjust if necessary is the length of the piston rod because when the beam is horizontal and the parallelogram has right angles the piston should be at mid-stroke between the steam ports. I've also built Clarkson's Steeple Engine. An experienced engineer wrote an article in ME in 1979 stating that the Steeple Engine was impossible to build due to multiple problems including drawing errors. He was not wrong! One of the drawing errors in particular is very difficult to work around with the castings as they were supplied.

Geoff

John,

Back home from Cornwall now (where I had another look at the Levant engine).

According to my drawings from Blackgates the links are:

2 at 3" centres

2 at 1 3/16" centres

2 at 3/4" centres

with a note confirming how important these measurements are.

Confirms, I think, your suspicions.

As an aside, I bought the plans with the idea of scratch building from stock. However, I was tempted by a set of all bronze castings (and the gears) on ebay 10 days ago but they went for more than I was prepared to pay - still good value though. Did anybody on here win them? I like the Sanderson because the parallel motion isn't obscured by it's supporting bracket.

HTH

Rod

John and Rod,

I've looked further into the parallel linkage dimensions to find the ideal length of the shorter anchor link using fixed dimensions for the horizontal and vertical links. I got the drawing board out and produced a drawing of the linkage several times scale size and marked on the linkage position with the beam up , horizontal and down. Using 3ins. (or a few thou over depending upon the casting bosses) and 1 3/16 ins. for the vertical links the required length of the anchor links is 3/4 ins. It looks like the length of the anchor link on the original Clarkson's drawing of 19/32 ins. is not ideal and that this has been corrected at some time to 3/4 ins. which will give a better result as now shown on the Blackgates drawing.

Geoff

Geoff and Rod

I'll try this again. I posted a reply to you Geoff on Sat morning but it seems to have got lost.

The dates on my plans are GA 18/12/68, the beam 14/12 96. and the links, 18/10/69. The dimensions for the beam holes are listed as 2 31/32 from piston pivot to link pivot, 1 3/8 to the beam pivot, 1 19/32 to the pump pivot and 2 3/4 to the con rod pivot, for a dist. from the beam pivot to each end of 4.34375. By centreing the holes in the bosses, my dimensions come out to be ( in the same order)3.023, 1.375, 1.592, 2.806, for a centre to end measurement of 4.398. It's strange the both our sheets with the drawings of the links bear the same date yet they have different dimensions. I bought my castings in May '80 ,when did you buy yours?

Your comments on the errors on the steeple engine are interesting as I have just finished building Westbury's Weyvern IC engine from castings I bought from Hemingway in Nov '13 and I found 7 errors in the drawings. Most are easily corrected if found before machining takes place, but the rear cam shaft bearing is impossible the way it is drawn. I checked the Heminway plans against the originals in the '63 issues of ME and they appear to be the same, so the errors have been there since day one.

Rod, Thanks for the dimensions,(different again) but seem to confirm what Geoff has come up with from his draughting board exercise as detailed in his last post.

I think I'll go with the following dims. 3.023, 1 3/16, and .75, seems to be the best results so far.

Thanks for all your help.

John

John and Rod,

My castings were an old set of Clarkson's castings bought about fifteen years ago. They are iron castings rather than the gun metal castings and aluminium base supplied these days by Blackgates. The old castings are to my mind preferable as the fluting on the connecting rod and column are finer. Also, certain parts actually need to be left bright steel which they cannot be with the gun metal castings with the result that certain areas end up painted which really should not be. The downside of the old Clarkson's iron castings is hardness which can be problematical. My drawings are also dated 18/12/68, 14/2/69, and 18/10/69 but the beam dimensions do differ. From the piston rod end the hole centres are 3-1/32, 1-13/32, 1-19/32, and 2-27/32. It is possible that these differences are a result of having new patterns made as over forty five years it is likely that there will have been more than the one set of patterns. The anchor link dimension though I think is different. It will have been changed at some time from 19/32 to 3/4 to be geometrically correct and to reduce friction/binding. Drawings like this from the 1960s were produced by a dye-line process using a translucent Velograph film and ultra-violet light. It was not uncommon for changes to be made by scratching out the old dimension on the film and writing in a new one. Sometimes you could detect the changes as they left a sort of halo around the dimension. There is a change on the Steeple Engine drawing like this with a halo although the new dimension is still incorrect. Usually changes are dated and described in a box at the bottom of the drawing but not so in the case of Clarkson drawings.

Geoff

Rod and Geoff

When I bought my castings (May '80,35 years ago the base was also an alum. casting), they had just come out with the gunmetal set for 68.33 pound (drawings gears P&P &VAT) I was tempted but on enquireing of the price to Canada it was almost double due to shipping. I also, like you Geoff, didn't like the thought of traditional bright steel parts in gunmetal or being painted. At least polished CI is a close colour to polished steel. My drawings are also of the dye-line process as they hung on the wall of my workshop in Winnipeg for a couple of years and I took them down when I noticed the had faded to about half.

After all these enlightning exchanges I think the explanation for the discrepancies in the drawings of the same date is that my drawings might be he originals and when the first castings were shipped the beam pattern ended up producing a cast beam the was ~1/8" longer overall than the drawing. When discovered the drawings were altered (you drawing Geoff) but mine never got altered.

That could explain why the dims. on your drawings are very close to the ones I came up with by centreing the beam holes in the bosses.

A note to the above. My cost for the castings drawing, gears, and shipping to PEI Canada in May '80 was 51.18.

That was the price of the drawings castings and gears plus 40% extra for shipping. The exchange rate at the time was very close to what it is now. Paid for by mail with a postal money order drawn in UK Pounds!

John

South of your border they would rejoice in all that bronze and polished them up to a blinding gleam

Definitely a cultural difference there.

Rod

Looks pretty, but hardly prototypical!!!

Hello again,

If you are interested in the history of Clarksons of York you will find useful information via the following link:

http://btckstorage.blob.core.windows.net/site12877/Documents/V17Iss2april2015_web.pdf

It leads to an article in the April 2015 Newsletter of the Leeds Society of Model and Experimental Engineers (England). It was written by Leeds SMEE members when Herbert Clarkson died. Herbert was one of our members. You will see my name within the pages. If you have any difficulty with the link I can send it in some other format. Blackgates recently unearthed some cardboard boxes full of old Clarkson's 1978 catalogues, a real piece of history, they still have some if you don't have a copy.

Geoff

Geoff

The link worked fine. The catalogue I have is the '78 version, and the price list is dated Oct '79. I also have the Steam-Paris flyer. I recall an article in ME on Clarkson's business with pictures of his facilities. It had to be in the early '80s but I cant find it in the ME indexes. The only one I can find was a couple of years before my issues start. Mine start in 1980 (actually Oct 1979). I'll have to go through them an see if I can find it. Can only be 3 or4 years, as the company ceased in '83.

John

John,

Have you tried this search. It is the one I use. Search on 'Clarkson' and you will get a lot of references to follow up!

http://www.itech.net.au/modelengineer/

Geoff

Geoff

Thanks for that link to the indexes. The ones I have been using up to now are those published by Colin Usher. These others seem easier to use. But still didn't come up the report I remember. It might have been titled under some other name. Or maybe I'm dreaming! The history in the LEEDS publication on Clarksons was very interesting. Thanks

John