Pressure canner calibration

Hey there! I purchased a presto pressure canner a couple of months ago. I’ve only used it for water bath canning because I haven’t been able to find somewhere to check the gauge on it for me. None of the extensions in my area seem to be able to do it, as every one that I’ve called either hasn’t returned my call or email or they just flat out say they can’t do it. Are there any other ideas for where to check for this service? Thanks!