Model IC camshaft cutting/machining.

[CedricParticipant @cedricblaver37709]

Hello all.

Please can someone advise on…..How to cut/machine a camshaft for a model IC engine.

I have seen on youtube a jig being used but cant find any plans on the making of it.

What is the easiest way to go about this please.

Many thanks.

[JasonBModerator @jasonb]

Can you give some details of the particular cam shaft as methods vary depending on what is needed. And/or what is the engine.

How many cams and are they integral to the shaft or loctited on?

Flat or radius flanks?

What do you have available to you? lathe only, mill, rotary table, boring head?

[bernard towersParticipant @bernardtowers37738]

Look up Westbury cam turning jigs or any westbury ic books usually have pics of them

[JasonBModerator @jasonb]

I understand from Cedric is it one of the Jung 2-cyl engine which have radius flanked cams. Similar to this but larger with a 30mm radius to the flank

So one option would be the Westbury jig that allows the embryo camshaft to be swung at that radius in the lathe.

However if you are like me and don’t make a lot of tooling there are a couple of other options particularly as it is a relatively short distance between the cams. Westbury wa swriting at a time when few hobby users had a mill so aimed his writing at those using lathes but we have moved on since then

One it to hold the blank in a chuck mounte don teh rotary table and pointing up vertically. You then set a boring head to swing teh 11mm radius and use a series of plunge cuts to do teh uppermost blank ancluding te hbase radius. Then starting from the next cam position repeat the process for the second cam and so on. This is quite easy to set up and do I first use dit on a Hoglet.

 

 

 

The other method is to use Cam-calc to produce a set of vertical offsets that let you set the Z height of the mill while the cam blank is held horizontally and rotated with a rotary table or dividing head. Again this method will do the base circle as well a sthe flanks and tip radius. Westbury’s jig only does the flanks. Just move to the next position and start at the appropriate angle.

 

You could also consider a built up camshaft with separat ecams bonded to a 6mm silver steel shaft which eliminates any risk of teh shaft distorting when you harden it. Plenty of Bobcats, Jaguars, Pumas and Oscellot engines base don teh Malcom Stride design running with this built up method

Thes edays I just whack them out on the CNC but the two method sI have shown work well and don’t need much that a reasonably well equiped workshop will have.

 

Cam-calc download

[JasonBModerator @jasonb]

Have a look at this thread for more about the jig

[Mark EasingwoodParticipant @markeasingwood33578]

Another thread HERE

The YouTube video mentioned in the above thread,

 

 

[IdlerParticipant @idle1]

You can also make a camshaft grinding machine with a rocking assembly that follows a template lobe. IiRC Charles Lamont plans are posted on one of the other forums, maybe HMEM.

And I think MEW published plans for another by ALex duPre or Jacques Maurel???

[Charles LamontParticipant @charleslamont71117]

I have not posted plans of my camshaft grinder. It is not good enough for that. There are some photos and a description here: https://www.model-engineer.co.uk/forums/topic/how-to-make-mini-camshaft/#post-716064

[bernard towersParticipant @bernardtowers37738]

Charles, I think a lot of ic engine makers would be glad to have a machine like that in the workshop.

[Roderick JenkinsParticipant @roderickjenkins93242]

Jason gave a link to my CamCalc.  I originally wrote CamCalc in Basic but when the Basic language disappeared as a free inclusion with PCs I wrote a version using Excel.  But, if you don’t have access to Excel, CamCalc works with full functionality using the spreadsheet in the LibreOffice suite which is a free open source download.

Like Jason, I would now cut my cams as individual items on my small CNC mill.  However, CamCalc does give the user some design information about velocity and acceleration which can be useful if you are designing your own cams.

Rod

[JasonBModerator @jasonb]

Even if you don’t have a paid for Excel Camcalc can still be run if you upload to OneDrive

[CedricParticipant @cedricblaver37709]

Thank you for all the help. this was a trial run using ally.

 

 

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