Jump to content
I Forge Iron

first trial towards forging a conrod


Recommended Posts

I have just hopefully posted a very short and poor vid of my first go at forging a conrod for a motor bike that I am buliding and some stills that you can see more detail, I need a new phone . The centre button of the die needs to be bigger in dia to push the metal further out but its replaceable so I will either be able to use the bigger one next time or step up through several sizes to get the result I need as my hammer is probably far to small but if I keep removing the flash so it dosent absorb any more force it may work

WP 20190524 15 53 48 Pro

WP_20190524_09_13_09_Pro.jpg

WP_20190524_15_41_41_Pro.jpg

WP_20190524_15_48_32_Pro.jpg

WP_20190524_15_54_30_Pro.jpg

WP_20190524_15_55_48_Pro.jpg

WP_20190524_15_56_03_Pro.jpg

 

WP_20190516_17_00_37_Pro.jpg

Link to comment
Share on other sites

  • 3 weeks later...

More progress with the conrod and a new phone yippie and I tried the proper die for the first time though I used the aluminum forging from the other die just to see what would happen and it looks ok. Now I need to make the central button that will form the centre of the big end and work out what shape the blank will need to be. I am going to do the trial forging using aluminum to reduce the chance of damaging my tooling. The cross section of the rod beam looks ok as well, the weight of the dies and mounting block adds about 10Kg to the mass of the tupp so that should help as well

20190615_152055.jpg

20190615_152111.jpg

20190615_152132.jpg

20190615_152246.jpg

20190615_152828.jpg

Link to comment
Share on other sites

  • 10 months later...

I have been busy in the workshop during the lockdown and made some good progress on my long term project. I have finally forged my actual conrod blanks out of the EN39B steel and I am very pleased with the result. I only need one but have forged four in total , Its been a long journey and I still have to do the machining myself and get profesonals to the crack, testing, carburising and heat treatment. i have been working up to this for the last few months experimenting with the preshaping of the blank to get the minumum amount of materail that would give me the desired result and the least amount of heat/hit cycles and because my hammer is really to small I got it down to three heats and lots of hits. I also made a new LPG fired forge to cut down on the formation of scale which will be a big bonus for knife making in the future and a second 2x72 linisher to complement my 100x2745 machine

20200403_141844.jpg

20200411_115104.jpg

20200405_140211.jpg

20200414_161421.jpg

Link to comment
Share on other sites

Here is a better vid from earlier in the year making slow progress towards what happen a few days ago, the billet I was using wasnt pre shaped much at all and required many heating/hit cycles which would of damaged the steel. The flame flash is from the graphite and grease lube i was using

Link to comment
Share on other sites

  • 2 months later...

some more progress and the conrod is all done apart from the final heat treatment/carburising of the bigend bearing surfaces and then hone to the final sizes. Its been magnafluxed several times. this part of the project has taken about two years and i have learned alot of different things and have been doing alot of work on other parts like the cylinder head and I am now getting into the fabrication of the frame

20200523_100213.jpg

20200523_125711.jpg

20200523_130244.jpg

20200620_162901.jpg

Link to comment
Share on other sites

Well actually Burt Munro came from and was based from my home town where I live Invercargill and is a great source of insperation to me, I have spent some time looking at his offerings to the Gods of speed at E Hays hardware store where a small part of his stuff and the original engine in a frame is displayed. And D harris yes I am making the whole bike except for the engine and suspenstion

Link to comment
Share on other sites

  • 3 weeks later...
  • 11 months later...

The conrod is all done it has been crack tested at three different times after the heat treatment cycles which were done by a profesional heat treatment place and the main bearing surface has been carburised and hardened then ground to close to the final size then honed to the finished size. The small end has had a aluminum brone bush shrunk in using liquid nitrogen and I used the remaining nitrogen to give it a backyard cryogenic treatment until it had all evaporated. When the rod bigend was carburised the rest of the rod was masked with a type of ceramic coating so it only has the high carbon case where its required, The rod was forged from EN39B steel. I have also forged a new kick starter lever as I couldnt get one the shape I needed, Its the middle one in the 2nd and 3rd pics and fitted to the bike in the last. Its forged from 4340 steel, I am buliding my version of a Yamha HL 500 replica and I am making the whole bike from scratch

20210428_095448.jpg

20210424_135730.jpg

20210424_163542.jpg

20210424_165130.jpg

20210509_141915.jpg

20210427_131555.jpg

Link to comment
Share on other sites

You went and did it didn't you? You've come up with a way to stand out in this bunch of oddballs. Scratch building a motorcycle is rather unique even here.

Too cool, I'll be watching for videos of the test ride.

Frosty The Lucky.

Link to comment
Share on other sites

Cheers Frosty yes I am a bit dranged LOL The plan is to havew it finished in a few months, there is still alot to do but I am getting there. The engine is being the victim of all the things that I want to try with a motor and I am going to race it in the Bert Munro motor cycle rally hill climb next Feburary as long as it hasnt blown up and goes and handles OK.

Link to comment
Share on other sites

I'm trying to imagine what it would be like if we were to combine the varied crafting skills and interests of all of our members into one collaborative motorcycle. So far, I've got:

  • alexandr to make the frame
  • jlpservicesinc to make the motor
  • Latticino to make a blown-glass gas tank
  • sidesaddle queen to make the seat
  • Steve Sells to do the wiring

Don't we have someone who's made steel-rimmed wagon wheels?

Link to comment
Share on other sites

  • 8 months later...

hqdefault.jpg?sqp=-oaymwEcCPYBEIoBSFXyq4

 

 

I have got my bike finished at last apart from some minor tuning, I am very pleased with how it runs I havent had it dynod yet so cant say how many horse power it has but it really gets up and boggies when it gets up in the revs. The rev limiter is set at 9000 revs and I have hit that a few times so the conrod is handling the pace so far. In the video at the start I hadnt turned the ignition on but once I did that it fired right up. The Burt Munro motor cycle rally week of the movie worlds fastest Indian fame was cancelled because of the plague covid so I didnt get to race it in the hill climb as I wanted but there is next year

Link to comment
Share on other sites

  Too bad you can't climb the hill at the ralley with it.  You should find another hill and try it out.  Quite the accomplishment others couldn't approach.  I've been following your progress on this thread.  A thumbs up. (Theres no thumbs up icon)....

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...