Pinning webs and journals on a built up crankshaft.

[Clive HartlandParticipant @clivehartland94829]

I have made all the components for a twin crank steam engine and the webs need pinning to the shafts.

The shafts are 5mm dia. and the thickness of the webs 4mm.

What type of pinning materiel do I need and where from?

I do have some 1.5dia pins but it seems far to thick for the job.

The shafts and webs are stainless steel type 306 I think.

Clive

[Clive HartlandParticipant @clivehartland94829]

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Hi Clive ,

By the normal design rules used in full size work your pins should have maximum diameter of only 0.85 mm diameter ( approx 1/6 of shaft diameter ) .

A very useful source of pin material this small is sewing needles – very hard , slightly tapered and consistent for size .

Realistically I think you could stretch the rules a bit and use 1mm pins to ease drillng problems .

MikeW

[1Participant @1]

Clive

Beware of using too hard a material for your pins, advice I took from Ramon Wilson who has described his method (search for "Pinning&quot on this site. To achieve a non-pinned look the pins and base material need to be similar. Ramon strongly counselled against piano wire.

When faced with my first pinning job on a Stuart 10V crankshaft a couple of days ago I used a paper clip for my pin material and the results are exactly what I wanted. Admittedly the shaft was not stainless but the clip I used was made of wire 1mm dia and the pins are invisible after a touch with a file and some wet and dry. As a book keeper I have a large selection of paper clips in varying sizes and hardnesses (not that I have ever bought a single one, people just send me stuff with a multitude of the damned things on and at last I seem to have found a use for some of them). Since I only ever run my engines on air, hopefully the paperclip and Loctite will be strong enough, if not – back to the drawing board!

Hope this adds a little to the debate

Jim

[Stewart HartParticipant @stewarthart90345]

I've found wood nails ideal material for pinning webs, nice and soft.

But why pin:- high strength loctite 603? will do the job if you get the fit of the webs correct:- a slide fit with minimum clearance.

Stew

[JasonBModerator @jasonb]

When I pin I like something soft enough so the ends of the pins can be peined over into shallow countersinks and then when they are filed flush become almost invisible.

If you need to go below 1/16" rod then look for some veneer pins rather than panel pins.

Failing finding anything a suitable small dia just turn down a bit of bar to say 1.0mm, its not that long a length required and if it turns out slightly tapered that could be useful.

J

[Ian S CParticipant @iansc]

The glue that I mostly use is Loxeal 8324 high strength/ high temperature retaining compound, got a little hot air engine here with a built up crankshaft of 3 mm diameter, the webs are 2 mm thick, all glued up, has not fallen to bits yet, no room for pins in that. Ian S C

[Clive HartlandParticipant @clivehartland94829]

Thank you Gents for your ideas and comments and I think I will go with the Loctite and S/Steel pins.

Clive

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