Hi jggh,
We are not aware of any reason why 3-1 oil should harm this oiler. However it is important to check with the oil manufacturer whether the oil itself is suitable for use with air tools as you would be potentially breathing in the vapour and also there is the possibility of dieseling, whereby the compressed oil vapour combusts under pressure causing a hazard to both tool and user.
If the manufacturer of 3-in-1 oil say that it should not be used, then you should use a purpose-designed air tool oil. Unfortunately Screwfix do not stock this but it is readily available elsewhere.
Thanks for using Screwfix Q&A.
Answered by: JTremain
Date published: 2016-12-18