[K9TAXI]

I'm building an over arm pin router for building guitar bodies. I welded some 3.5" steel tube to make the arm and bolted a z-axis to the arm. Z-axis is using an RM1610 ball screw. My z-axis has a NEMA 34 motor mount. I have about 8" of travel. The z-axis will be manually controlled using a step/direction pulse generator and a joystick. All I need to do is move the router up and down to position the bit at the correct depth then I release the joystick and I move the wood around by hand.

My router is a Bosch 1617 EVS 2.25 HP and weighs 10 lbs (4.5Kg). I have no idea how much torque is needed to plunge the router bit into the wood and then hold it steady at that depth. In the past I used a linear slide table with a hand crank and it didn't take that much force to plunge the end mill into the wood. I'm thinking this application isn't going to need much torque especially since I'm moving the router up and down slowly. Do you think I could get by with a NEMA 34 rated at 4 Nm? I have no practical experience with steppers except in a lab. I think a 12Nm rating would be way over kill. I'd appreciate any input on this.

[cncmakers001]

I'm building an over arm pin router for building guitar bodies. I welded some 3.5" steel tube to make the arm and bolted a z-axis to the arm. Z-axis is using an RM1610 ball screw. My z-axis has a NEMA 34 motor mount. I have about 8" of travel. The z-axis will be manually controlled using a step/direction pulse generator and a joystick. All I need to do is move the router up and down to position the bit at the correct depth then I release the joystick and I move the wood around by hand.

My router is a Bosch 1617 EVS 2.25 HP and weighs 10 lbs (4.5Kg). I have no idea how much torque is needed to plunge the router bit into the wood and then hold it steady at that depth. In the past I used a linear slide table with a hand crank and it didn't take that much force to plunge the end mill into the wood. I'm thinking this application isn't going to need much torque especially since I'm moving the router up and down slowly. Do you think I could get by with a NEMA 34 rated at 4 Nm? I have no practical experience with steppers except in a lab. I think a 12Nm rating would be way over kill. I'd appreciate any input on this.

4Nm should be enough, but if the price of bigger motor is not so big different, you can choose a bigger motor.

[peteeng]

Hi Taxi - usually a 5mm pitch screw is better for plunging but since you have 10mm then if you have a 4Nm motor, 4Nm at 10mm pitch will produce a force of 230kgf. If the motor is moving its torque will be less say 3Nm so it will be pushing with 173kgf still heaps for plunging into timber.... Mind your fingers!! Peter