Suggestion to secure a crankcase for fly cutting

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charkmandler
Posts: 48
Joined: Sat Apr 29, 2017 8:11 pm

Re: Suggestion to secure a crankcase for fly cutting

Post by charkmandler »

Thanks Roundnose, I like your suggestion of using a rotary table although not an option for me as the cost of a large table could not be justified. I would outsource the work but can't guarantee that it would be done properly; a recognised machine shop ground a gearbox shaft for me and it was .005" out over and inch - criminal! I built and raced vintage bikes in the 80's and had a much bigger mill then. Did several crankcases, just couldn't remember how I held them and ran in to a brick wall of creativity with setup on the smaller mill I now have.

Got a good setup now for the crankcases with repeatable testing measurements. But delaying cutting the crankcase mouth as I'm not happy with the large sweep the fly cutter has to take and want to cut it in one sweep so making a 'heavy' disc cutter for the job - something I've put off for a long time and a tool I will use a lot.

My vintage pushrod, rigid rear end, girder forked bikes were in the top 5 results in vintage / classic racing in the UK, beating overhead cam bikes from the 60's. I spent a crazy number of hours making sure everything was 'square' and know this was the difference between the top bikes and the also rans.
John Evans
Posts: 2366
Joined: Tue Jan 20, 2009 9:33 pm
Location: Phoenix ,AZ

Re: Suggestion to secure a crankcase for fly cutting

Post by John Evans »

Clark: Several years ago on a Goodwood live feed there was a mid 30s Rudge Radial running in second place between 2 Norton Manx's . Girder/rigid in the rain to boot !!
www.chaski.com
charkmandler
Posts: 48
Joined: Sat Apr 29, 2017 8:11 pm

Re: Suggestion to secure a crankcase for fly cutting

Post by charkmandler »

Yes, Mervin Stratford has been developing a radial 250cc ridge since the early 80's and that used to beat the 2 strokes. Good rider as well.
John Evans
Posts: 2366
Joined: Tue Jan 20, 2009 9:33 pm
Location: Phoenix ,AZ

Re: Suggestion to secure a crankcase for fly cutting

Post by John Evans »

You must be in the UK ? I'm a old Brit bike lover ,had everything from Ariel to Velocette and Vincent back in 70s-80s . My main interest was in 500CC singles but had 2 Sq-4s a Vincent Black Shadow and a Greeves Silverstone !!! Back when that stuff was cheap to buy I always 6-8 roadworthy . To old now to ride a solo ,balance not too good. But a sidecar ,now that is another story. Had a half dozen over the years from a Panther 650 with a Busmar D/A to a BMW R69S with a Wixson.`
www.chaski.com
charkmandler
Posts: 48
Joined: Sat Apr 29, 2017 8:11 pm

Re: Suggestion to secure a crankcase for fly cutting

Post by charkmandler »

Hi John, yes in the UK. Sounds like you've had some fun with bikes. I've been lucky enough to ride in most types of motorcycle sports and am still having fun riding, hopefully for many years to come. The historic scene in the UK was great in the 80's without too many regulations. Some very good riders.
TimTheGrim
Posts: 115
Joined: Sat Sep 13, 2003 2:47 pm
Location: El Paso, TX

Re: Suggestion to secure a crankcase for fly cutting

Post by TimTheGrim »

I’m glad I could be of some help.

Life being what it is…I haven’t had a chance to move forward on my engine work due to being “pulled” out of retirement to work on a couple metal stamping dies in a pals shop. Daily die shop work really keeps one mentally sharper, but I also realize just how fortunate I am to have what I have in my home shop.
My muscle memory sometimes gets in the way on other folks machines.
Illigitimi non Carborundum
'96 Birmingham mill, Enco 13x40 GH and Craftsman 6x18 lathes, Reid 2C surface grinder. Duro Bandsaw and lots of tooling from 30+ years in the machining trades and 15+ years in refinery units. Now retired
AllenH59
Posts: 479
Joined: Wed Mar 16, 2011 1:26 pm
Location: Prince George BC Canada

Re: Suggestion to secure a crankcase for fly cutting

Post by AllenH59 »

This was the best set up thread I have read. Thanks guys.
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