By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Forum House Ad Zone

Wyvern crankshaft question

All Topics | Latest Posts

Search for:  in Thread Title in  
NR6714/05/2022 14:47:11
avatar
40 forum posts
10 photos

All the parts are now machined for the crankshaft of my Wyvern engine. My question is about the best way of joining them together. As far as I can tell the pins are a tight push fit into the plates but I dont want to push them fully home until its all aligned. Silver solder, Loctice 603, Straight knurl and press in, pinning are various methods Ive read about. Ime minded to loctite and maybe pin because once completed I guess the engine will be run for 10 minutes a year, no more. soldering may need further machining if it spreads too far and ide rather not. If I loctiite is it best practice to machine a shallow groove in the pin so there is space for it, especially if they are tight fitting? Any ideas greatly appreciated.

Thor 🇳🇴14/05/2022 15:39:19
avatar
1766 forum posts
46 photos

I have made built up crankshafts using anaerobic glue and pins. My pins could be pushed in by hand so I didn't groove the pins, the crankshaft is still working 2 years later. I have also made built up crankshafts that I have silver soldered (brazed) together, I machined the crankshaft after soldering and pickling.

Thor

JasonB14/05/2022 15:52:17
avatar
25215 forum posts
3105 photos
1 articles

I usually silver solder built up cranks for IC engines and keep the Loctite for steam and hot air where things are a bit more gentle.

PatJ14/05/2022 16:41:35
avatar
613 forum posts
817 photos

As I understand it, all of the single cylinder motorcycle engines have pressed together cranks, with no pins.

So if it works for a motorcycle engine, why not use it for models?

Perhaps too tedius to try and press in the pieces without damaging something?

Is there a special method used to press together motorcycle cranks?

Just curious.

.

bernard towers14/05/2022 17:52:46
1221 forum posts
161 photos

Modern single motorcycle cranks are a press fit but also the shafts are taken from liquid nitrogen in a controlled atmosphere, we can't do that plus our engines do not put out massive amounts of hp per cc

duncan webster14/05/2022 18:13:16
5307 forum posts
83 photos

The crankpin holes on old British bikes were tapered so you Coul push them nearly home but still adjust by putting between centres and hitting with a lead hammer. Having broken a hydraulic jack trying to dissemble a loctite joint I have great respect for it

NR6716/05/2022 06:47:47
avatar
40 forum posts
10 photos

I decided in the end to use loctite and in stage 2 to cross drill and pin, again with loctite. Assembly in 2 stages. First the big end journal with a temporary main bearing journal that was continuous to keep alignment. A temporary spacer between the webs keeping them parallel. Second phase is to fit the permanent main bearing journals. A jig to ensure these are in perfect alignment and clamped is for today. Probably a piece of ground bar and parallels used in a temp arrangement. Thank to all for the various ideas and information on crankshaft construction.

Samsaranda16/05/2022 09:44:30
avatar
1688 forum posts
16 photos

I remember my Matchless G80 crankpin had thin nuts locking the outer ends of the crankpin. Dave W

Nigel McBurney 116/05/2022 10:27:42
avatar
1101 forum posts
3 photos

A mild shrink fit,then secure with taper pins driven home hard, too severe a shrink fit does not improve the fit as the metal surrounding the shaft or crankpin just stretches. a full circular crank disk having a central shaft can have a tighter shrink fit as there is a lot of metal surrounding the shaft and the disc will not stretch. A friend made a couple of crankshafts for the Model Gardner engines out of solid using en 24 no problem with those,though he is a good machinist. Graham Corry of Alyn foundry silver soldered his cranks for the Gardner and other models,I made 4 of the Robinson hot air engines and with such a low power Loctite made a good job of it and requires no cleaning,Graham used a high temperature silver solder flux to get a clean joint .

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Sign up to our Newsletter

Sign up to our newsletter and get a free digital issue.

You can unsubscribe at anytime. View our privacy policy at www.mortons.co.uk/privacy

Latest Forum Posts
Support Our Partners
cowells
Sarik
MERIDIENNE EXHIBITIONS LTD
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest

 

Donate

donate