- Joined
- May 3, 2020
- Messages
- 346
I replaced my pneumatic power draw bar with the Grizzly unit (H8368). Here's the experience so far. I'll probably review it after a few months of use. If I do, it will be farther down this thread.
I've been using the usual paddle-switch pneumatic air-powered inpact driver on my drawbar for the last few years. I bought it on eBay and have had some trouble with it. It's always leaked here and there. At one point, I had to take apart the regulator and fixed a faulty soldering job. The switch also does not return to neutral, joints leak, etc. When I pull the unit down, despite being a 12-point socket, it almost never seats on the drawbar, forcing me to turn the socket a little by hand and try again. I'm always fiddling around, trying to get it to work. But it does work.
I bought the electric unit so the compressor doesn't run so much. The shop is 6' x 7' and the noise is oppressive. Also, it's attached to the house, so less noise is appreciated by everyone.
The electric unit comes with a kit of parts and you need to make a new drawbar. The instructions say you should cut the drawbar off to fit your mill, then thread it into a splined shaft that mates with the motor. I didn't want to deal with the prescribed threads and set screws so I just drilled a hole (close sliding fit) and used a roll pin instead. I also made a washer to keep the drawbar centered in the top of the spindle and a bearing-bronze washer for good measure. Because the spindle protrudes above the top of the mill, I had to make a spacer. I used a 3" long section of aluminum tube (McMaster) that was 5" OD.
I measured the hardness of the spline that mates with the motor. It was 25 on the Rockwell C scale, which is fairly soft. So I took a lot of measurements, in case I ever need to make a new one.
I wired it into the control box of the mill. Then I attached the drawbar's control box to the cover of the mill's electrical box. It comes with a bracket for installation on the right side of the mill but the holes in the box aren't centered. Anyway, when you press the button, there are 2 stages. A light press engages a solenoid that pulls the drive mechanism down onto the splined end of the drawbar. A heavier press starts the motor, which is geared down and has an impact function.
It took a bit of work to get the unit installed. At first, it did not always engage properly. I thought it might be an alignment problem. After working on it for a while, I got it to engage most of the time. I am in the habit of rotating the spindle to get proper engagement. That's fine, except in lower gears in which case it's very difficult to turn the spindle by hand. When it doesn't engage, you hear the sound of an apprentice driving a philips screw with a cordless drill. I eventually filed a lead-in on the top of the spines and added a couch-destorying amount of moly-d grease to the spline. Hopefully I'll learn to feel when it's engaged and whatever other tricks you need to operate this efficiently. I can definitely feel and hear the engagement if I take the spindle out of gear and listen carefully. But the point of the upgrade was to avoid annoyances like these. Seems to work OK but only 100s of tool changes will reveal the truth.
Other cons: the price (1,400 + tax) and the height. And the cover interferes with the fan shroud on the spindle motor.
I've been using the usual paddle-switch pneumatic air-powered inpact driver on my drawbar for the last few years. I bought it on eBay and have had some trouble with it. It's always leaked here and there. At one point, I had to take apart the regulator and fixed a faulty soldering job. The switch also does not return to neutral, joints leak, etc. When I pull the unit down, despite being a 12-point socket, it almost never seats on the drawbar, forcing me to turn the socket a little by hand and try again. I'm always fiddling around, trying to get it to work. But it does work.
I bought the electric unit so the compressor doesn't run so much. The shop is 6' x 7' and the noise is oppressive. Also, it's attached to the house, so less noise is appreciated by everyone.
The electric unit comes with a kit of parts and you need to make a new drawbar. The instructions say you should cut the drawbar off to fit your mill, then thread it into a splined shaft that mates with the motor. I didn't want to deal with the prescribed threads and set screws so I just drilled a hole (close sliding fit) and used a roll pin instead. I also made a washer to keep the drawbar centered in the top of the spindle and a bearing-bronze washer for good measure. Because the spindle protrudes above the top of the mill, I had to make a spacer. I used a 3" long section of aluminum tube (McMaster) that was 5" OD.
I measured the hardness of the spline that mates with the motor. It was 25 on the Rockwell C scale, which is fairly soft. So I took a lot of measurements, in case I ever need to make a new one.
I wired it into the control box of the mill. Then I attached the drawbar's control box to the cover of the mill's electrical box. It comes with a bracket for installation on the right side of the mill but the holes in the box aren't centered. Anyway, when you press the button, there are 2 stages. A light press engages a solenoid that pulls the drive mechanism down onto the splined end of the drawbar. A heavier press starts the motor, which is geared down and has an impact function.
It took a bit of work to get the unit installed. At first, it did not always engage properly. I thought it might be an alignment problem. After working on it for a while, I got it to engage most of the time. I am in the habit of rotating the spindle to get proper engagement. That's fine, except in lower gears in which case it's very difficult to turn the spindle by hand. When it doesn't engage, you hear the sound of an apprentice driving a philips screw with a cordless drill. I eventually filed a lead-in on the top of the spines and added a couch-destorying amount of moly-d grease to the spline. Hopefully I'll learn to feel when it's engaged and whatever other tricks you need to operate this efficiently. I can definitely feel and hear the engagement if I take the spindle out of gear and listen carefully. But the point of the upgrade was to avoid annoyances like these. Seems to work OK but only 100s of tool changes will reveal the truth.
Other cons: the price (1,400 + tax) and the height. And the cover interferes with the fan shroud on the spindle motor.
