Drill press burning wood

[Jason Ferris]

I recently picked up a 17” Delta Rockwell 3 phase drill press that dates from the 1950s. I cleaned it, replaced the bearings in both the motor and spindle, had the chuck calibrated by a machinist, and connected it to a VFD. All was well, so I thought.

But it burns every kind of wood I try to drill. Taking the same bits to a hand drill, I get no burning at all. I’ve tried to alter the speed, but this doesn’t seem to help. Any idea what is causing this?

[johnny means]

Can we assume that the rotation is in the right direction?

[Jamie Buxton]

Is the drill press running backwards?

[Jason Ferris]

Wow, the simple answer is often the correct one. It was indeed running backwards! This is my first time using a VFD. Thanks for your help.

[johnny means]

Wow, the simple answer is often the correct one. It was indeed running backwards! This is my first time using a VFD. Thanks for your help.

You have to always check with 3ph machines.

[Charles Lent]

To run the other direction, just swap two of the three motor leads. It doesn't matter which two. A three phase motor is very easy to change the direction this way. Then forward on the controller really will be forward at the drill bit.

Most VFDs also have reverse capability, and you can buy reversed drill bits (left hand or CCW). I find this capability great when trying to drill out a broken bolt. The reverse rotation sometimes backs the bolt out without the need to actually drill the hole for the EZ Out.

Charley

[Derek Cohen]

I recently picked up a 17” Delta Rockwell 3 phase drill press that dates from the 1950s. I cleaned it, replaced the bearings in both the motor and spindle, had the chuck calibrated by a machinist, and connected it to a VFD. All was well, so I thought.

But it burns every kind of wood I try to drill. Taking the same bits to a hand drill, I get no burning at all. I’ve tried to alter the speed, but this doesn’t seem to help. Any idea what is causing this?

Jason, what you describe is almost always due to the speed being too high. Slow it right down. I suspect you have not done this enough.

Regards from Perth

Derek

[Larry Edgerton]

I was all set to see a wood burning drill press, Dang. Would be great in the winter.

[Bill Dufour]

To run the other direction, just swap two of the three motor leads. It doesn't matter which two. A three phase motor is very easy to change the direction this way. Then forward on the controller really will be forward at the drill bit.

Most VFDs also have reverse capability, and you can buy reversed drill bits (left hand or CCW). I find this capability great when trying to drill out a broken bolt. The reverse rotation sometimes backs the bolt out without the need to actually drill the hole for the EZ Out.

Charley

The left hand bits are hard to find so I always use a regular bit to start the hole. They can skate off the broken angled end and snap. So I get a small dimple or under sized pilot hole not more then one diameter deep then switch to the left hand bit. They do work many times.
Bil lD

[Charles Lent]

Bill,

I bought one drill index full about 20 sizes of left hand bits over 40 years ago from WT Tool. I don't use them often because I only use them for drilling out broken bolts, but the index is still full, and a life saver when it's needed.

I have several drill indexes of good quality right hand bits that are used for most of my drilling needs including the fractional, number, and letter sizes. I even have a metric set, and if I break one of my drill bits I make a note to myself and get a replacement. I even have Forstner bits in 1/8" increments from 1/4" to 3 1/2" diameter. I hate it when I need a certain size drill bit and I don't have it.

Charley