Recent content by BobNZ

If making "hacksaw blades" from broken bandsaw blades that still have reasonable teeth, then mark out the length and where you want holes. The holes can be punched easily using a punch and hammer with a suitably sized nut under the blade allowing the punched divot to drop away from the blade...

A spark eroder is versatile and with a bit of skill applied, can remove a broken tap or cut any hard material as long as it electrically conductive. You can build your own. Do a search on spark eroder, tap eroder, tap disintegrator, metal disintergrator or EDM. There are many DIY designs plus...

Crankcase modification for big end, gudgeon plus some bore lubrication, along with the possibility that scavenging of oil, many be needed depending on whether you plan on a "dry" sump with pressure fed lubrication or a wet splash system. Rings will need to be modified to cope either way. All...

Air flow though some motors is better than other and some motors are encased as protection in volatile environments, so rely on external fins for cooling. The field coils and the armature both heat while the case temperature is affected more by the field coils heating in the short time frame...

It depends on what noise you wish to reduce. Constant fan hum can be a bit distracting and is unnecessary when the VFD is not driving a motor or is under very light load. The fan is for cooling so ambient air temperature must be taken into account when looking at modifying fan operation. There...

Agreed Nick. A motor may not take the increased centrifugal forces of higher RPM. Balance and shaft stiffness along with bearing design are relevant factors. A sloppy guide may be if the motor is 4 pole and a similar motor of the same brand and style is 2 pole, then you are probably OK...

The 220VAC single phase to 220VAC three phase VFDs I have had good success with, can control the speed but with a caution to not exceed double the rated motor RPMs for mechanical reasons, nor significantly lowering the rpm below the motor rated rpm, if the motors are under heavy load. For...