Woodruff key in camshaft

[volker.halbach]

I had sent off my camshaft to Draganfly. I got another refurbished camshaft back. They also sent me a new No.3 Woodruff key. The Woodruff key has a very loose fit in the camshaft and is too high and too long. Shouldn't the key just fit without any filing? I assume the fit in the camshaft should be a press fit. Of course, they might just have sent me a camshaft with a mangled key way; but I am now wondering whether I need another Woodruff key.

[simon.holyfield]

You need another key. There should be no play in any dimension - the only thing you should ever have to do is a bit of deburring or perhaps lose one of the pointy ends, e.g. if the gear is close to a thrust face.

[volker.halbach]

Any idea what I need? The radius is correct.

[JohnnyBeckett]

HI maybe they pick up the wrong key out of the box i have had it with their case screws , i think it is their suppliers get it wrong

[Paul Gasson]

Hi Volker, the key should be a precise fit in the cam and gear as Simon mentioned. It must be the wrong one you have received. I had a similar problem from Drags with a crankshaft key for a 500cc Triumph, it was way too narrow and not deep enough to hold the alternator rotor in place. I spoke to them and was told they had been advised the part sent was a suitable alternative but I could not use it. I think you need to contact them, good luck with it. It might be worth a check to verify the valve timing when you get the key issue resolved.

[volker.halbach]

Thanks to all. The parts book specifies a No.3 key and the key has the dimensions that I found for such a key. But I have no idea about norms for Woodruff keys. I'll talk to Draganfy. Paul, I'll check also the valve timing.

[volker.halbach]

I measured everything again. The key is too narrow by 4 thou both in the camshaft and the gear wheel. I can just squeeze in a feeler blade of that thickness. So it must be the key, and the slot in the camshaft is ok. The parts book specifies a No.3 key, which is exactly what Draganfly sent me, at least according to the dimensions I found for a No.3 key according to ANSI standards. I am beginning to suspect that 'No.3 Woodruff key' means different things to Americans and 1930' Brits.

[simon.holyfield]

Maybe compare the ANSI standard with BS46 for imperial keys? I think Simply Bearings stock imperial sizes.

[simon.holyfield]

[volker.halbach]

Hi Simes,

Thanks for the table! I think I have solved the conundrum with it. Sometimes it's helpful to switch to metric measurements. The key from Drags is exactly 3mm wide, which is 0.007" less than 1/8", which is the width of the key 404 in the table. Add 7 thou and the key from Drags would have a very tight press fit. They simply sent me a metric key. That should be easy to solve.