Tiny Vertical Based On G. Britnell's Design

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sbwhart:
Thanks chaps

--- Quote from: ImIndoors on December 11, 2014, 11:33:19 AM ---I take that Liz is on the Minnie Mum wage? :clap:
Jim

--- End quote ---

:lol: :lol: :lol: Nice one :thumbup:

Now for the connecting rod:-

A chunk of 10mm brass bar was first roughed out in the spin-indexer.

Then using a 2mm slot drill mill little end fork and drill.

I also marked the position of the big end split line and the position of the bore with a spotting drill to aid alignment for later ops.

The onto the lathe for turning down the middle, and parting off.

Gripping it square in a small vice and lining up on the part off pip and the spot marks zero DRO.

Drill M1 tapping.

Cut off the bearing cap again using the spot marks to get position.

With the cap cut off tap M1

Then open up cap to M1 clearance 1.2mm

Screw the cap to the rod and set up on centre and drill 2.5mm.

Job Done

Stew

steampunkpete:
Sir, I've just put my hat on so that I can take it off to you. You have made a lovely thing. :beer:

sbwhart:
Cheers guys.

On with the eccentric:- as the engine will have reversing linkage the eccentric will have a double throw, it took me a while to get my head around George's method I also complicated things a little in changing his design half way through only to find that if I carried on I would not be able to assemble the arms so I had to start again, any way this is the sequence.

First make an off centre bush with a 1mm throw by packing out one of the chuck jaws.

The bush was drilled and tap to take a M3 grub screws.

Then on the 3/8 bar that the part will be made on mill a couple of flats 132 deg apart from each other using the spin indexer

Then in the lathe turn the little boss and drill 2.5mm

Then mount the bar in the off centred bush using a grub screw with a flat bottom so that the bar is pulled up level when it tightened up.

Turn up the first throw 6mm dia.

Then mount the bar locating on the second flat, and using a part off tool as the the first throw will get in the way, turn down the second throw to 6mm

Then over onto the mill and drill and tap M 1.6 for the eccentric clamp screw.

Back onto the lathe and part off

That's it Job Done.

Stew

sbwhart:
We're really getting down to working with 2/10 of bugger all now :)

Eccentric straps

I know it getting a little repetitive when I say in the spin-indexer but this is really the best way I can think of for holding these small parts.

So first up In the spin-indexer machine up a blank to make both straps back to back.

Then drill the holes in position and to the required size.

Then mill to shape

Mill the fork end with a 1mm slot drill:- yes I did say a 1mm slot drill I bought a couple of good quality Hertel drill they cut beautifully didn't break any at all.

Then slit them down the middle to form the two straps and cut them off the bar with a hacksaw

Mill them to final thickness

Mounted them on a mandrel to form the back.

Then filed the rad and tidied off the burrs

That's it job done

Cheers

Stew

sbwhart:
Managed to get another bit made today in between baby sitting my 2 yr old grandson. :Director:

The quadrant link

Mounted a bit of thin mild steel plate to the rotary table that I had centred under the mill, then drill out the holes where required.

Then with the 1mm slot drill mill the radius slot and the outside profile.

Then it was just a matter of gently filing the rest of the profile.

Stew

IS THERE ANY ONE OUT THERE :wack:

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