# Strange keyway?



## 12bolts (Dec 7, 2012)

Stripping down to repair an old compressor, i found this keyway in the pulley.



It is wider than the key would be to fit in the shaft and quite a large radius for what I do not know.
The corresponding keyway in the shaft is like a standard woodruff key.


The pully is 10"dia and has been tapped and fitted with a grubscrew. (just visible in pic 1 at about 1o'clock) The bore is tapered to match the shaft taper and is also retained by a bolt and large washer threaded into the end of the shaft.
I have never (I think) seen a key that would be of the design required to fit these 2 parts together.
Suggestions?

Cheers Phil


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## Bill Gruby (Dec 7, 2012)

When the pulley was put on the shaft, that hole was drilled between the shaft OD and pulley ID. The pin that was inserted into the hole is referred to as a "Dutchman". It kept the pulley from spinning on the shaft the same a key would. The two black dots are Dutchman Pins.

 It looks as if that pulley may have had another home prior to this one.

"Billy G" )


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## 12bolts (Dec 7, 2012)

Thanks Bill, I have seen dutchmans' before. The "keyway" for want of a better word in the pulley is also tapered, but at a faster rate than the taper in the bore so it actually starts off quite large and then by the time you reach the other end of the hole it is non-existant. Also if it were a dutchman you would expect to see it inserted from the other (small end) of the bore, as if you were to fit it from the large bore side would require considerable working room between the pulley and the machine to drill said hole.

Cheers Phil


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## ddmunroe (Jun 6, 2014)

My first thought is that it is home made, but in saying that it must be effective starting more into the pulley then veering more in to the shaft. I doubt it's part of any industry standard.
dd


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