Llewellyn Loco Works #1

[dewintondave]

Hey new fella, nice work!

Best wishes,
Dave

[Hydrostatic Dazza]

Done , but for breaking the edges, all was spot on and fitted nicely on the slide bar and the piston rod slid in. A lot of work for these little fellas!

[Big Jim]

Very impressive, I thought I was handy enough in a machine shop until I saw the item coming out of your works. There seems to be a great deal of engineering skill in the southern hemisphere, is it down to the water?

[Hydrostatic Dazza]

Very impressive, I thought I was handy enough in a machine shop until I saw the item coming out of your works. There seems to be a great deal of engineering skill in the southern hemisphere, is it down to the water?

Thank you for the kind comments. I am terribly slow, I mull over every thing 10 times ............................

[tom_tom_go]

So do I if not more so and you still do a better job than me!

[mymodeltrain]

Engineering can be learned but you are born to do it; very creative. I also like this hobby where family members enjoy to involve in the process.

[Keith S]

What a talented and fastidious machinist you are. I wish I could see some of this happening in real life. It seems almost like magic. Oil holes in miniature connecting rods! The nerve!

[Hydrostatic Dazza]

What a talented and fastidious machinist you are. I wish I could see some of this happening in real life. It seems almost like magic. Oil holes in miniature connecting rods! The nerve!

Thankyou for the compliments, I picked up the how to 0.50mm holes with PCB carbide drills at another forum http://modeleng.proboards.com/

[ge_rik]

Incredible attention to detail ...... I marvel at such precision. I think my tolerances are nearer to +-5mm!

Rik

[Hydrostatic Dazza]

Working on the connecting rods. The B.W drawings has a small end pin at 3.2mm diameter going into a 2.50mm Con rod hole. I am not a fan of a steel pin running in the plain steel small end of the Con rod so I am intending to use 2.50mm pin (case hardened) and run it in a 0.40mm wall PB bush in the small end of the Con rod. The small end rod eye I made bigger to 5.20mm to give more room to accommodate the the bush. Much easier to replace a flogged out bush, if the need ever arises. The crank in the Con Rod to my mind very annoying and if there was to be a next time I would investigate the feasibility of redesigning the whole gig with a straight rod. I calculated I needed to make the Rod centres 0.14mm greater than the 80mm I have in my drawings, so the 80.14mm centers on the flat rod will be 80mm when the 2.40mm crank is inserted/pressed/bent. My dimensions may vary from the original drawings.





Made a pair of 5.20mm diameter filing buttons from some 1/4" silver steel and a 10 BA screw to hold them. Hardened the buttons with no tempering.
All set for the saw and file tonight.



Good batting by Roy last night.

[Hydrostatic Dazza]

Incredible attention to detail ...... I marvel at such precision. I think my tolerances are nearer to +-5mm!

Rik

Thanks, but not really incredible
Cherry Hill and her work is incredible.
However these live on my head a lot of the time

$27.00 aud from Jaycar
while I bump or trip over every second obstacle

[Big Jim]

Engineering can be learned but you are born to do it

This is very true, Having had dealings with a number of the apprentices over the years, you can spot a natural. Skills can be learned, techniques can be honed
but aptitude is a gift. I know I can teach anyone to weld (I taught the wife), but there is a big difference between some one who can weld and a natural welder.

[tom_tom_go]

They 'weld' natural ability boom boom...

[Hydrostatic Dazza]

Silver steel filing buttons, hardened right out and a 10 BA screw



file file file, sand sand



each weighs in at 4.45 grams according to Solid Works.



What is next here ?

[Hydrostatic Dazza]

[daan]

Now I know your secret.. You have a very well trained staff of dedicated workers to help you. For them all the small fiddly scale stuff is normal size and therefore easy to make..

[Hydrostatic Dazza]

Now I know your secret.. You have a very well trained staff of dedicated workers to help you. For them all the small fiddly scale stuff is normal size and therefore easy to make..

Yep, they are the brains and brawn of the whole "Potters Orchid Railway" gig
They have even been published

Me, I just do the marketing stuff
If I can get them to make the bikes then I could go fishing or hang out at some heritage railway and sniff stream oil and chew some coal while sipping tea

[Hydrostatic Dazza]

Fiddly work.
Slide bars in place and the cross heads are moving, attached to piston rods.
Left hand side needed .02mm removed from the bar at the cylinder end and .20mm at the MB mount.



The dummy bolt heads that were loctited in fell out with the constant handling. I will clean and refit some replacements later.



The right hand cylinder needed .20mm shim at the MB mount.







I have concerns about the drag with the quad rings that I used on the piston.
Next is the bushes and pins and complete the con rod.

[Hydrostatic Dazza]

I have introduced a Phosphor Bronze bush to the small end of the connecting rod. I was not keen on a 1.60mm wide steel con rod flogging about on a 2.50mm steel pin. A bush can be replaced, but correcting an oval hole in the small end of a con rod, "Errrrr yukkkkkk!" ( Errrrr yukkkkkk= Dazza technical term)
I also made it wider at 2.80mm to give more wearing surface. So while ABC Jazz radio played I started turning small and big end bushes. After some redrawing I got the centre line of the piston rod to the centre line of the con rod small end and reduced the crank in the con rod to 1.50mm which reduces the sideways forces and possible wear. Other wise the cylinder cover and gland takes up the lateral thrust as the cross head is not designed to. The vertical thrust is taken up by the slide bar and cross head. OK, the forces are small, but.......................

[Hydrostatic Dazza]

Machining the cross head pins, will be case hardened later this arvo.