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I think my drill head is jammed

Posted: Wed Jul 05, 2017 10:22 pm
by rawbutter
I recently bought a Harbor Freight 3-in-1 off craigslist (a Central Machinery T5980). One of these:
https://goo.gl/photos/r8U2HckyshbNm5S56

The seller said it was brand new, but I'm having trouble getting the mill to work. The motor turns on and spins (sometimes), but the gear chuck for the drill part won't move. At first I thought the pulley tension was dialed up too tight, or too loose, but when I opened up the top to change the tension, I ran into my first problem. The pulley tension is really tight....so tight that I can't get it off. So that might be part of the problem.

The solution to this seemed easy. This is a picture of the inside of the top.
https://goo.gl/photos/LP3QuQnKGoRMKHT46

There are three bolts around the motor gears on the left. I figured that if I loosen those bolts, then I can get enough slack to take off the pulley. But if you look closely, loosening the bolts only allows me to move the motor more to the left, which increases the tension instead of loosening it.

So am I missing something really obvious here? Or do I need a new pulley? Any help is appreciated.

Oh, and I'm not sure if this is related, but I can't get the gears on the right to move at all (the mill). It doesn't matter if the motor is on or not. Which seems odd to me. I can easily move the lathe gears by hand if the machine is unplugged, but the mill gear seems stuck. Not sure if that's normal or not.

Re: I think my drill head is jammed

Posted: Thu Jul 06, 2017 1:26 am
by spro
Hi. Welcome to the Board !. It would seem loosening those bolts would allow the tension to be reduced but there is that square headed bolt which prevents that section from sliding. It could be the belt was cinched up really tight, too tight and a bearing seized. Face that possibility later but right now, take out those bolts and drop the motor (figuratively as cords and stuff may need detaching). Seizing is a big thing and that is why you need to find out now. Find out where that is.. I know this is so old advise but may help.

Re: I think my drill head is jammed

Posted: Thu Jul 06, 2017 3:07 am
by Harold_V
rawbutter wrote:There are three bolts around the motor gears on the left. I figured that if I loosen those bolts, then I can get enough slack to take off the pulley. But if you look closely, loosening the bolts only allows me to move the motor more to the left, which increases the tension instead of loosening it.
I am not personally familiar with that machine, but I question if what you say is correct. Is it possible the motor and pulley are mounted to that plate, and will move the required direction, assuming you back of that square headed screw? If so, you should be able to move it by hand, once the bolts are loose enough and the square head bolt is backed off.
Oh, and I'm not sure if this is related, but I can't get the gears on the right to move at all (the mill). It doesn't matter if the motor is on or not. Which seems odd to me. I can easily move the lathe gears by hand if the machine is unplugged, but the mill gear seems stuck. Not sure if that's normal or not.
It's not clear to me what gears you speak of. Can you post a picture?

Once the belt is removed, the spindle should turn freely. Do keep in mind, the spindle is housed in a quill, which does not turn. If you can't turn the inner portion (the spindle) freely, there's an issue with the spindle, likely failed bearings.

H

Re: I think my drill head is jammed

Posted: Thu Jul 06, 2017 6:28 am
by Torch
If I look at your picture closely, it appears there is some slotted hole peaking out on the left of the washers on at least two of the motor bolts. Loosening the bolts and then loosening the big black adjuster bolt -- as already mentioned by spro and Harold -- should gain you some slack.

If this machine is indeed brand new, it is possible that the sand from the casting process was not thoroughly washed out before assembly (a common problem with some Chinese factories). If some grit made it's way into a bearing, the bearing will be very rough or jammed even if it's not actually seized in the traditional. melted metal, sense.

Re: I think my drill head is jammed

Posted: Thu Jul 06, 2017 9:46 am
by rawbutter
Thanks for the replies, everyone. I should have mentioned that I did loosen the big black adjuster bolt when I tried to move the motor. That didn't help. But I can try again, just to be sure.

If I am looking at a jammed or seized bearing, what's the next step? Can I force it loose if I put some kind of t-bar in a chuck and give it a good turn, or do I need to disassemble the whole thing and replace the bearing?

Re: I think my drill head is jammed

Posted: Thu Jul 06, 2017 12:36 pm
by rawbutter
Okay, I think I got it fixed. Running with the jammed bearing idea, I clamped down on the mill gear with a monkey wrench and gave it a gentle tug. It moved a little, so I gave it another wiggle. Something gave, it moved more freely, and eventually through more gentle wiggling I was able to rotate the gear freely. Once that was done, the pulley was easy to change, and the motor ran the drill fine. I'm still a little surprised that the motor wasn't able to push through a gunked up bearing, but maybe that's by design so it doesn't break something.

Thanks for the help!