Member postings for Ron Laden

Finished the test rad with a medium and fine file followed with an emery wrapped file. I thought a couple of light coats of paint would show up the finish and shape, quite pleased with it, if I can copy that on the cylinder I will be happy. .

Should have the alu block for the cylinder Monday and not having milled an outside radius before thought a bit of practice could be useful. The length of the cylinder block will be 60mm but I only had a piece of 30mm but ok for practice. I was thinking of cutting the rad with the side of an end mill but at 60mm and even with a long series cutter I would still need to turn it over and cut it from both ends.

I then remembered from one of Jasons build threads him cutting a radius with a series of facets and finishing by hand, that seemed a good idea so gave it a try. I worked around the rad in 3 degree increments and must admit it wont need too much work with the file for a good finish (thanks Jason). I did machine away the bulk in advance so it wasnt too many cuts for the rad, really enjoyed doing it.

Edited By Ron Laden on 05/10/2019 16:55:04

I came across a picture of a Wallis and Steevens roller, what an odd looking engine with the boiler slanting steeply down towards the rear. At first glance it looks as if the boiler is broken into two and collapsed, certainly different though from a modelling point of view, I cant imagine there are too many of those around.

Another of my basic working sketches showing the cylinder at actual size, I have indicated the 3.5" block it will come from.

I have drawn the bore at the size it would be with a piston and liner but of course there is no piston so it will come down to 12mm dia. I am going to extend the cylinder cover into the bore to offer a bit more support for the piston rod, probably by about 5 mm that will make the cover 20mm deep overall, the piston rod is 6.5mm dia.

Thats the plan anyway.

Just ordered a 3.5 inch square piece of ali for the cylinder block, I am going to try and machine it in one on the mill using the rotary table. I think it can be done or at least I hope so, I have worked out a plan of attack but we will see.

Also I have been searching the Minnie drawings for the pin which connects the crosshead to the conrod but of course there isnt a drawing. The pin is described in the build though as a piece of hardened silver steel which runs in the conrod with no bearing. I am going to turn up a thin walled bronze bearing as Jason suggested to me and fit that to the conrod. I have also been thinking about the crosshead guide which on the Minnie are the pair of parallel bars but I do like the idea of the cylindrical guide I have seen on other engines. The ones I have seen have been from castings but I wouldnt imagine too difficult to produce from round bar, dont know yet, undecided.

Thanks Jason, great advice as always.

I was only going to go with a shallow csk but never thought about distorting the plate which I can see now. The ctr punch method sounds quick and easy so thats good. Also reducing the number of stay rivets is good news as I did wonder if I had too many and seeing your picture above I can probably reduce by half.

Thanks again.

With a pen and rule I roughed out a layout for the rivets in the hornplate to get a feeling for how they would look. Just based it on a mix of full size and model engines but I think it will look ok. Going to csk the holes on the inner face of the plate and dress back flush. For the stay rivets I,m still trying to find some shallow head type if they exist.

Edited By Ron Laden on 01/10/2019 13:30:03

Thanks Paul, quite a bit more to it than I imagined, I think it probably a good idea if I got a couple of books on TE,s and had a good read.

You mention differential, I know I dont need one but I like the idea of having one, Jason posted a good compact design for one a while back.

Ron

I wrongly assumed that the layout of the main parts/build of traction engines would be the same or similar across the various manufactures/designs. However looking at some pictures of a scale model Burrell I see it has no second shaft and the high/low gears and shift are fitted directly to the end of the crank.

I dont know what type of full size engine the Minnie is based upon but I wonder why they went down that path. Fitting gears to the end of the crank is simpler, cheaper, more compact etc, maybe just a different approach unless there other benefits of a second shaft.

I assembled the crank using 638, I am going to pin the webs but waiting for pins to arrive. I was keen to see if it had turned out true, I havnt clocked it but it looks pretty good by eye so happy with that.

A bit of exciting video below of it running in the lathe.

That looks a very sweet runner Derek, you must be pleased with that.

Ron

A shorter version oiler which I,m happy with.

Just wondered are mush head rivets available in model eng sizes, I saw some truss head (I think thats what they were called) but they were very shallow, more so than a mush head.

Edited By Ron Laden on 26/09/2019 13:59:14

Very true Harry, thats a bonus I guess.

No not happy with it, its too tall and the more I look at it, it looks odd. Oh well a re make job.

Made up and fitted the big end oiler this morning, no its not to the Minnie drawing but some parts wont be though the majority will. I found the body in my odds and sods box and it just looked like a potential oiler and about the right size, all I had to do was turn the base under the ball to create a spigot for fitting. Then I turned up a brass cap, its a couple of mm taller than I would have liked but cant do much about that, there is a M4 threaded rod inside the cap which screws into the body and needed the length of cap to thread for the rod. I dont have a knurling tool but managed a light knurl by running the cap along under the edge of a file.

Edited By Ron Laden on 26/09/2019 09:25:14

Thanks Harry, the last link in that thread Nuts and Bolts for Model Engineers do a good range of BA, metric and UNC. They also have a very good range of one size smaller BA plus their pricing looks good.

Ron

Oops, sorry posted in wrong thread, deleted it.

Edited By Ron Laden on 25/09/2019 21:05:57

Bob, I have a Mitutoyo Digimatic which is well over 30 years old and it still works but I do have to nurse it along. My problem is battery related also, I have to keep cleaning the contacts or the display dims even with a new battery fitted. Also the central contact which is angled upwards has lost its spring so I have a thin washer between the battery and battery cover to maintain contact.

Have you thought of giving the Mitutoyo service dept a call, I have been meaning to but havnt got around to it yet. They may have a standard charge for repair/service of their products, but it may also be a case of replacement parts plus an hourly rate and other charges which costs more than the calliper is worth.

I will have to look into it as I would like to keep it going, its till very nice to use and head and shoulders above the cheapo versions.

Thats sounds a lot to me, I would have thought a 3 1/2" could come down to half that radius as a minimum but maybe not, it does surprise me though.