Rays Latest Engine - AKA Alyn Foundry RLE

[RayW]

Finally got the cylinder head problems sorted.
Re-made the valves, both to the same length, and with 5mm silver steel stems and stainless heads silver soldered on. Ground them both in with fine grade grinding paste until there was a nice even ring showing on both the valves and the seats. Fitted a very light spring for the inlet valve and a slightly heavier one for the exhaust. Modified the collets to give slightly more room for the springs.

Drilled and spot faced the four fixing bolt holes in the head casting, then clamped it to the cylinder and spotted through to mark the holes for the fixing studs. Drilled and tapped the holes 2BA.

The attached photos show the two body castings, cylinder, hopper and cylinder head roughly assembled to show progress to date. The front of the upper body casting still needs opening out a bit as it is currently slightly narrower than the mouth of the cylinder.

[Alyn Foundry]

Good afternoon Ray.

" All's well that ends well " as the saying goes, your pictures say it all.

You've reached that stage that I used to start to dread, the " fiddlely bits " ! I really like machining castings but I found the smaller parts both tedious and time consuming.

I forgot to ask, are you going to cut your own gears? I used to supply a pair as an optional extra. I used the services of HPC and because of " bulk " buying was able to pass them on at a good, and discounted price.

Young Alan has just picked up on his shelved  R.L.E. engine again, he line bored his mains on the Denbigh yesterday evening.

Cheers Graham.

[RayW]

Hi Graham,
I have no experience of gear cutting so will probably have to resort to bought ones. I know that you mentioned some time back that you still had some gears and offered me a pair. Are they still available please and, if so, how much are they?

[RayW]

Managed to get the crankshaft finished just before getting ready for the MEM virtual show. Only thing left to do is the oil hole in the piston and crankshaft. The piston has been fitted with its Viton O rings and compression already seems pretty good.
Next job is to line bore the main bearings and open out the front of the main casting to clear the cylinder bore.

[RayW]

Drilled and reamed the main bearings today and machined the front of the upper body casting clear of the bore. With the main bearing caps fitted, the crank revolves quite freely and the piston moves smoothly in the cylinder.

[RayW]

Completed machining of the two flywheels yesterday.

I must have been having bit of brain fade when cutting the keyways because I had meant to line them up with one of the spokes for strength, but completely forgot and they have ended up between spokes. I will just have to be careful not to use too much force when fitting the keys to avoid splitting the centre boss.

Not only that, but I didn't even think about ensuring that the keyways were in the same position on each wheel, so that the spokes lined up when fitted, but, by a piece of amazing luck, they line up almost perfectly, so the engineering gods must have been looking down on me!

[Alyn Foundry]

Good morning Ray.

We always put our keyways between the spokes. If you get a " stubborn " key in the future you can always resort to a hammer and drift from the other side if all else fails. 

You're getting on nicely, well done. 

Cheers Graham.

[RayW]

That's what I must have been thinking of subconsciously!

[RayW]

I have just been looking at sources for spur gears for the engine and there seems to be very limited choice of suppliers, and I am just wondering where other RLE builders have obtained theirs.
Unfortunately, I have neither the knowledge, skill or equipment to make them myself, so will have to buy them commercially. If anybody knows of any good suppliers please let me know. I have looked at HPC Gears and I can get a pair of 52 and 26 tooth 40DP gears from them, but they want over £30 for the pair.
Ideally,the larger gear needs to have a large enough boss to bore out to 7/16" and be milled to a cam shape, although a separate cam could be silver soldered on if necessary.

[Jasonb]

Ray have you machined the position for the cam gear stud yet?

If not you could move things a little bit closer and use metric gears. If you went with readily available MOD1 and 16/32T that would give a PCD of 24mm, your DP gears have a PCD of 24.75 so only need moving 1/32" Even if drilled an eccentric pin will soon sort things out. MOD0.8 with 20/40T would also work with the same 24mm PCD

less than half the price from the likes of Belting on line who I have used a few times
https://www.beltingonline.com/gears-racks-leadscrews-366/spur-gears-367/metric-0-5-to-8-mod-375/?zenid=92cekrsbvp1feh5stqtbhrjgs3

EDIT if you want to go the other way and stretch them apart then MOD0.8 with 21/42T gives a PCD of 25.2mm which is closer to the original 24.75mm but MOD 0.8 nare not as easy to find in odd numbers

[Jo]

I have just been looking at sources for spur gears for the engine and there seems to be very limited choice of suppliers, and I am just wondering where other RLE builders have obtained theirs.

I cut my own: http://www.modelenginemaker.com/index.php/topic,7664.msg163018.html#msg163018

The original gears were Mecanno 38DP but all things Mecanno seem to be expensive. MoD 1 spacing would match the casting shape better. IF you can wait a couple of months you could buy them from China for about £5 for the pair.

Jo

[Alyn Foundry]

Good morning Ray.

As Jo has stated I used a pair of Brass Meccano gears on 103. Back in the 1980's they were readily available and very reasonably priced. I soldered two together for the half time wheel to get some extra thickness. The problem was that after many hours running at the rallies, they wore out.

Whilst at one of the many " Subcon " events the trio discovered HPC Gears who were handing out their little books. These books were a mine of information as well as a product reference guide. As a consequence I was able to buy in large quantities and pass the discount on to my customers.

The mainframe casting has a " generous " area for mounting the half time wheel. I used to make an eccentric bush of about 10 mm outside diameter with the 2 BA  threaded hole offset. This allows you to get the mesh just right.

If you have a rotary table with indexing plates you could easily " knock out " a couple of wheels in next to no time. A single point tool, with the right form, used like a fly cutter on the milling machine would suffice. They don't have to be perfect as their duty is very light.

Cheers Graham.

Edit.

Following up on Jason's MOD 1 suggestion I did a quick eBay search and found several suppliers of Steel gears that are available. It seems a 15:30 ratio might work for just under £20.00 for a pair.

[RayW]

Thank you Jason, Jo and Graham for your advice and suggestions. I have now ordered a pair of Mod1 16 and 32 tooth gears from Belting On Line for less than £20 including VAT and postage. Quite a bit different from HPC.

[Jasonb]

And if you are lucky the gears can be sawn down the middle so you have a spare set for another project making them even more cost effective.

[RayW]

Received the gears today from Belting On Line. The smaller gear, which has to be bored out to 7/16" to fit the crankshaft  is going to be quite a challenge as the root diameter of the teeth is only 1/2", the same as the boss diameter. This means that when bored out there will only be 1/32" wall thickness left, both in the boss and in the gear itself.
My proposal is to silver solder on a larger boss, say of the same outside diameter as the gear. This will both strengthen the gear, and provide a thicker boss wall for the grub screw to secure the gear to the crankshaft. My only concern is how to avoid the silver solder flowing into the teeth. I have, in the past, used Tippex to limit the flow of solder, so I wonder if painting the teeth with that would keep them solder free.