Super slow drill press

[84-1074663779]

Holesaws are useful for making manifold or turbo flanges in half inch steel plate, but the typical drill press is far too fast, even with a coolant pump fitted.

What I have done is remove the motor from a cheap secondhand drill press, and replaced it with a 10:1 (worm) angle drive reduction gearbox. A matching pair of rather large cone pulleys were then fitted onto the vertical gearbox output spindle and the chuck drive shaft.

The original vee belt tension lever, now works directly on the gearbox, and it gives me four alternative speeds. The belt needs to be very tight because there is a lot of torque. But it WILL slip if the holesaw jams which is actually a good feature.

The original motor was then slung under the gearbox with the shaft horizontal. Four pieces of all thread allow the motor to be raised and lowered to adjust belt tension. But as the torque is less, the belt does not need to be tight. The belt can be moved between the cones without moving the pulley centres. Belt slip is no problem because the belt and motor is so lightly loaded.

The two original cone pulleys were used to drive the 10:1 gearbox.

I now have 16 speeds ranging from around 14 RPM to 490 RPM, and this particular drill press has an automatic power feed as well.

This drill press is now able to cut three inch holes in half inch plate with the holesaw becoming only slightly warm to the touch. It is slow work, but no more blue teeth.

I also have some pretty big morse taper drills that can be used in my slow drill press. Being able to drill one inch holes or larger in thick plate is actually quite handy without either burning out the drills or the drill motor, or making jagged triangular holes.