bonded crankshaft

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bonded crankshaft

This topic has 44 replies, 21 voices, and was last updated 20 January 2010 at 18:27 by David Clark 13.

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15 January 2010 at 16:27 #47412
steve williams 3
Participant
@stevewilliams3
HI GUYS

JUST DRAWING UP PLANS FOR MY NEXT I/C PROJECT AND I HAVE HEARD PEOPLE TALK ABOUT BONING THE CRANK TOGETHER INSTEAD OF S/SOLDERING AS I HAVE IN THE PAST. HAS ANYONE TRIDE IT IF SO CAN U RECOMEND A PRODUCT

LOOK FORWARD TO ANY COMWNTS CHEERS

STEVE
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15 January 2010 at 16:27 #2255
steve williams 3
Participant
@stevewilliams3
15 January 2010 at 16:52 #47414
Circlip
Participant
@circlip
Beef in preference to Lamb.

Regards Ian.

Any chance of a spull chuck David DC1 ?????????????

Edited By Circlip on 15/01/2010 16:55:08
15 January 2010 at 17:08 #47417
Engine Builder
Participant
@enginebuilder
Hi Steve

I have made 5 1/2 size hit and miss type i.c. engines. I used loctite high strength adhesive on the first cranckshaft and after running for I guess about 30 hours, the joint failed. I would’t risk it again and now I always silver solder. There is an intermitent load on this type of engine. You may get away with adhesive on a smaller constant speed engine.

David
15 January 2010 at 18:18 #47420
Rob Manley
Participant
@robmanley79788
Ideally, loctite should always be used in conjunction with a mechanical lock, like a good fitting pin. The shock loading received by an I/C crankshaft makes this type of fixing probably the worst type. Loctite requires an extremely small amount of clearence between the two components like an medium slide fit and degrease like mad. If you were going to loctite it, pin it also making sure the pin is a tap fit.

Rob
16 January 2010 at 01:00 #47430
Ian S C
Participant
@iansc
Although I havn’t tried it yet,I think it would be OK on the likes of a hot air engine where the stresses on the crankshaft are low and not the shock of a IC engine.Ian S C
17 January 2010 at 13:03 #47482
Ramon Wilson
Participant
@ramonwilson3
Hullo Steve
Regarding your request
I have made several cranks over the years using Loctite successfully but these have all been in lower stress environments i.e. steam engines. I have always doweled the crank pin to the web or web to the shaft (using a mild steel ‘dowel’ again using Loctite to retain it) peening it over and filing it back. If this is done carefully there is little, if any, evidence.>>

> >

You don’t say whether your engine is a single or multi throw, if single I would try to make the crankpin integral with the web and try to bond the web to the shaft with as wide a surface area as possible as well as doweling it. (I have just done this to the Nova diesel engine, see album) If a multi throw – or single pin double webbed – then try to make as many webs as possible integral with the individual shaft parts bonding (and pinning) the remainder along with the crankpins. >>

> >

Personally I am reluctant to use silver solder because of heat distortion on parts previously machined as well as possibly altering the characteristics of the materials used. If it was soldered then I would want to machine it to size after – somewhat defeating the object of making and bonding parts together.>>

> >

Finally I would totally agree with Rob Manley – Loctite needs to be used correctly to achieve the best result. The correct grade and the right kind of fit and, as said, degrease the parts well. When you fit the dowel, file a (very) small flat along its length to allow the Loctite to escape, as the dowel is pushed in this will ensure the dowel goes fully home and won’t be pushed out again by the compression of air.>>

> >

Hope this of some help to you, any further questions please ask.Best of luck with your new design.

Regards – Ramon

Edited By Ramon Wilson on 17/01/2010 13:06:15
17 January 2010 at 13:44 #47483
Engine Builder
Participant
@enginebuilder
Using such a big font is like SHOUTING!
17 January 2010 at 13:54 #47484
John Stevenson 1
Participant
@johnstevenson1
.

He’s perhaps deaf himself, or blind ?

.

Edited By John Stevenson on 17/01/2010 13:55:10
17 January 2010 at 16:10 #47488
Funnyturn
Participant
@funnyturn
Using a large font is not shouting, but using capital letters/upper case is.

Entries are much more readable if typed in upper and lower case, a space is added after a full stop and an extra line added between paragraphs. Good old fashioned punctuation is nice aswell!

Brian
17 January 2010 at 17:41 #47492
Richard Marks
Participant
@richardmarks80868
Give the man a chance, he may not be computer literate, some people have to learn as you or I did be it engineering or typing.

Dick
17 January 2010 at 18:02 #47494
Niloch
Participant
@niloch
I also suspect Ramon copied and pasted a MSWord document of his. I’ve recently had experience of doing that and, wherever, a new paragraph was started in the original MSWord document and after pasting a couple of emoticons unintentionally appeared at the end of each paragraph/beginning of the next. Perhaps Richmond could have a look at this phenomenon.
17 January 2010 at 18:34 #47496
Ramon Wilson
Participant
@ramonwilson3
Hi, I had hoped that a response would have been about the problem at hand and how to deal with it but theres nothing like jumping down some ones throat. No I’m not deaf and certainly not blind. If I’m guilty of anything it’s that I really thought I was trying to do someone a favour.

Regretably unlike some I’m no computer literate though I do know that using capitals is shouting. I’ve been having problems trying to sort out large type on most pages in the last couple of days particularly on the google webpage and emails to no avail and

I did copy the text from an MS doc as I wanted to make sure that I got it right before posting even then I had to edit.

It’s funny that no one has responded to what I had to say on the engineering side but my thanks to those who jumped to my defence.

My deepest apologies if I offended someone – I will need to think twice before posting again.

Regards- Ramon

Edited By Ramon Wilson on 17/01/2010 18:36:39

Edited By Ramon Wilson on 17/01/2010 18:37:30
17 January 2010 at 18:43 #47498
Richard Marks
Participant
@richardmarks80868
Ramon,

You should not be the one to apologise, If as you say you didn’t get an answer to your question then what is the point of a posting criticising your computer skills, the point of this site is to help people with their engineering problems.

Regards

Dick
17 January 2010 at 19:14 #47499
Peter Gain
Participant
@petergain89847
Back to the original (sensible) post.

Glue is for woodworkers. There is something “not quite right” about glueing metal. Metal should be joined by rivets, welding, brazing, soldering, nuts & bolts, & etc. Even without sophisticated test equipment these methods can be assessed for “goodness”. But the only way to be sure that a glue joint is sound is to use destructive testing. Not very productive! Much more satisfying is to persevere & turn press fits for the crank or if appopriate, silver solder & clean up on the lathe. Even the advocates of Loctite suggest a mechanical fixing in the form of a pin. Loctite is excellent for what it does best; it locks threads. To achieve a press fit is not dificult, just practice some simple turning. Plenty of Workshop Practice books available to assist.

Peter Gain.
17 January 2010 at 21:02 #47508
ChrisH
Participant
@chrish
Hi Ramon,

I read in disbelief the responses to your post, I just couldn’t believe their crass nature and rudeness. Please disregard the posters – they are a bunch of rude plonkers and should be ashamed of themselves!

Comments like your post is what is required:

Could I read it – yes

Was it relevant – yes

Was it informative – yes.

So OK, the font was big but so what? It can be read. So what is the problem? I thought the content was good – just for the record.

Now, re the content, I guess you are using a dowel pin through the crank pin in the same way as a shear pin would be used. I did wonder if a dowel pin used in the same way as keyway would work well. How big are the steam engines you have used this method on?

I have also thought about the heat factor of silver soldering on the properties of the metal and the effect it would have on it and on the finished dimensions.

Regards,

ChrisH
17 January 2010 at 23:33 #47510
Ramon Wilson
Participant
@ramonwilson3
Ok Guys, lets put this one behind us. I would just like to say however that I am only interested in using this forum to share what knowledge I have with those less knowlegeable and to learn from those with much more. End of subject let’s move on.

Having said that it’s late. I have just spent some time on a lengthy reply to Chris and Peter using this ‘box’ and not an MS doc so that I didn’t repeat my previous misdemeanor. Unfortunately I took too long – as I went to post it the computer timed out and I lost the wretched lot!

I will reply in the morning in the meantime sleep tight – Ramon
18 January 2010 at 00:33 #47511
Martin W
Participant
@martinw
Ramon

Re losing your post this has happened to me more than once when I have taken too long to submit it.

What I do now is wait until I’ve finished and before submitting it to the forum and with the cursor still in the posting I ‘Right Click’ on the mouse and when the menu comes up ‘Left Click’ on the menu ‘Select All’ at this stage all of your text should be highlighted, mine comes up with white writing on a blue background. Then ‘Right Click’ mouse again and on the menu ‘Left Click’ on the menu ‘Copy’, I then ‘Left Click’ anywhere in the ‘Post’ to return the text to normal and submit the post. Then if you do lose your first post all you need do is to open another ‘Post a Reply’ box and ‘Right Click’ to get menu and then ‘Left Click’ on ‘Paste’ and your post should appear. Quickly, well fairly, submit to forum.

Hopes this helps and you do not stop submitting to the forums.

All the best

Martin W

Edited By Martin W on 18/01/2010 00:37:56

Edited By Martin W on 18/01/2010 00:40:15
18 January 2010 at 10:45 #47519
Ramon Wilson
Participant
@ramonwilson3
Thank you Martin, I’ve tried that out so hopefully the same thing won’t happen.

Ahhh! ‘Loctite’ nearly good as metric versus imperial for good debate.

Peter you are right that glue is for wood but Loctite is recognised as an industrial adhesive and if used in the correct manner using the correct grade then joints should give service under most conditions. I have used this both as a model engineer and in my work for many years and have yet to see a correctly (sorry to labour the point) assembled joint fail.

That said given the circumstances of’ ‘Engine Builders’ experience it shows that like most things there are limits. Considering this was a half scale model running ‘hit and miss’ probably turning a hefty flywheel over some thirty hours that’s an awful lot of ‘bangs’ before failure. I’m not decrying silver soldering such components merely pointing out that personally I prefer to use Loctite for the reasons previously mentioned – no distortion and no heat related stresses. Had EB dowelled the joint the failure may possibly not occurred (note may and possibly)

When press and shrink fits are involved there are some pretty strong forces involved none of which can be ‘felt’ If over done particularly in cast iron then the stress can lead to cracking and if underdone then it’s weak any way.

Some time back I made several cast iron liners with a 1mm wall thickness sized to a plug gauge. When these were press fitted to the ally barrels they all had to be re-honed to the gauge again – quite a lot of work which would have not been necessary had they been Loctited. That was one time when I really did wish I had used it!

Loctite comes in many grades each designed for a specific purpose – I’m not intending to be flippant here but fitting a bolt with ‘retaining compound’ is going to cause some serious problems in the future and likewise fitting a crank pin with ‘thread locker’ will prove disastrous.

Regarding the actual assembly Chris – when I said mild steel I should have said silver steel for that is what I have always used. I have always fitted them in shear with the hole pointing down the web and drilled just through the crank pin into the other side.

I did take a few pics of the Mc Onie engine crank build and will post them on the Albums.

Cranks so far built this way are a 5 “g GWR 0-6-0, Stuart twin Victoria, the McOnie and a Double Diagonal.

Hope this of help – this is not intended to disagree with others just another opinion to Steves original question – he has to analyse the opinions and come to his own conclusion what to do on his next build.

Regards for now and if this doesn’t post I’ll give up!

Ramon
18 January 2010 at 13:59 #47523
Rob Manley
Participant
@robmanley79788
Oh and one more reason not to use loctite – it ain’t half expensive! A one thou per inch press fit doesn’t cost a penny aslong as you don’t consider you time too valuable.

Oh and every time I see capitols used I always imagine brian blessed talking, so Ramon that’s who i’ve got in my head now keep up with the good advice.

Press on
18 January 2010 at 16:15 #47531
Donald Mitchell
Participant
@donaldmitchell68891
Hi engineers,

Last year I made a 1/3 scale Amanco Hired Man, I loctited the crankshaft and also fitted pins. after about 1 hour running it began to fail, only the pins holding the thing together.

After swearing a bit, I took it apart, cleaned it and reassembled with silver solder, all is still well.

Loctite is great stuff in my book for most things but obviously not well suited to the shock forces in my hit ‘n miss I.C. engine.

Keep making swarf.

Donald Mitchell
Castle Douglas
Bonnie Scotland
18 January 2010 at 16:53 #47533
steve williams 3
Participant
@stevewilliams3
I’D LIKE TO SAY THANKS FOR THE ADVICE ON MY ORIGINAL POST ON BONDING CRANKSHAFTS

I AM SUPRISED AT SOME PEOPLE THOUGH MANY THANKS TO RAMON FOR TAKING THE TIME TO GIVE ME SOME OF HIS OBVIOUSLY VAST EXPERIENCE. PITTY NOT EVERYONE IS SO HELPFULL

CHEERS RAMON

STEVE
18 January 2010 at 17:59 #47536
chris stephens
Participant
@chrisstephens63393
Hi Donald

Which grade of Loctite did you use, how did you clean the surfaces, what gap did you leave for the Loctite and did you design the joint with enough area for an adhesive to stand a chance?

I am not poking fun, you understand, just doing a little survey. Would anybody else like to offer the same information on any failures, so we can get an idea where to use and where not to use Loctite.

chriStephens
18 January 2010 at 20:15 #47541
Ian Abbott
Participant
@ianabbott31222
A couple of comments.

I’ve used Loctite in many very high stress situations, but never in what you’d call a reciprocating part such as a crankshaft journal. Did use the bearing mount on a Perkins V8 diesel crankshaft harmonic balancer / front pulley when the fine splines had worn because the bolts hadn’t been tightened at the factory. I put a sheet of two thou brass shim around the tapered, splined shaft and pressed the pulley on to create a spacer, which was then trimmed to size. After I’d degreased the parts several times (belt and braces), I used primer and a coat of bearing mount. I checked the bolts and the pulley for movement every twenty hours up to a hundred, then figured it wasn’t going to come loose. As far as I know, it’s going still.

It’s common practice to use press fit crankshaft journals on motor cycles, they don’t quit, even without Loctite. Well, maybe not never.

I think that the problem comes with multi cylinder crankshafts, when flexing takes place due to the uneven pressures on each journal at differing times. On older I/C engines such as pre-war (2 that is) cars with three bearing cranks, broken shafts were common, and spectacular sometimes when different bits of the crankshaft did different things, like leaving the crankcase.

On some of the Royal Enfield bike crankshafts, the big end journals are threaded on the ends and a very shallow nut lies in a recess on the outside of the crank web keeps the bits out of the way.

Ian
18 January 2010 at 20:17 #47542
Bowber
Participant
@bowber
I think most IC cranks are under too much stress and heat to use loctite type joints.

Press fit or turn up in one part is about the only way.

Steve
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