No, not as strong as welding. I'd like to know how he prepares the fit of the parts. I agree with machinist that it would be only suitable in my opinion where it is in compression or shear. You'd have to do some machining to create a sleeve like fit of the parts and maximize surface area. I'm not sure what the objection is to welding the bolt handle. The heat remains quite localized if its done right. Its not overly time consuming and can be finished to look like it was never anything but one piece of metal.
Adhesives have come a long way, so it would be interesting to know more about this process before writing it off, but without knowing the exact methodology, I'd say this is best not done at home.