Drill Press "Knock"

[Journaler]

So I got this Drill Press off Craigslist.

http://menards.com/main/tools-hardw...-presses/12-drill-press/p-1498047-c-10086.htm

Put it together, and powered it on.
Everything seems to be working except there's a "knock" coming from the motor somewhere. With the unit unplugged, I can rotate the belt and cause a slight tick sound coming from the motor/shaft somewhere.

I took the belt off, and ran it with no knock. I put the belt back on, and the knock was gone, but came back a short time later.

The belt seems brand new, as does the rest of the drill press. The guy sold it to me with the original box+manual etc.

Any ideas what could cause the knock?

 

[sickboy motors inc.]

Did you check the pulleys for out of round?

 

[DavidB]

Probably a problem with one of the bearings in the motor. The belt pulls on the shaft which puts a sideload on the bearings and can cause the knock to be worse than if the belt was not on. Pull the motor and take it apart. The bearings can be removed and replaced pretty easily.

 

[Journaler]

I didn't exactly check for that, but if it is out of round, it's very slight.

When slowly turning the belt, the tick sound is very much a tick. I imagine that with a pulley that's out of round, it would sound different? I'm tempted to take the motor housing apart, perhaps I can actually see what's making contact.

 

[Journaler]

Probably a problem with one of the bearings in the motor. The belt pulls on the shaft which puts a sideload on the bearings and can cause the knock to be worse than if the belt was not on. Pull the motor and take it apart. The bearings can be removed and replaced pretty easily.

That sounds reasonable. I'll try that, and see.

Thanks!

 

[Outlawmws]

First I'd make sure the pulley is on tight setscrews are not allowing a clatter. Some pulleys use a double set screw, so watch for that.

 

[jtbinvalrico]

+1 on the seating of the pulley on the motor shaft and checking the set screw.

 

[Journaler]

Well, the set screws were pretty tight.

I guess I'll have to take the motor off the drill press, and see about checking those bearings.

 

[larry_g]

Have you checked the fit between the pulley and the shaft? The pulleys should be a slip fit on the shaft. If you can rock the pulley on the shaft with out the set screws being tight then no amount of tightening of the set screws will fix it. Also if you do not have the shaft well engaged in the pulley you can have problems.

lg
no neat sig line

 

[Journaler]

I understand the first part: with no belt, and no set screws, the pulley on the shaft should not wobble at all.

I don't understand the second part: "if you do not have the shaft well engaged in the pulley you can have problems." What does "the shaft well engaged in the pulley mean"? How can I check for that?

Thanks!

 

[larry_g]

I don't understand the second part: "if you do not have the shaft well engaged in the pulley you can have problems." What does "the shaft well engaged in the pulley mean"? How can I check for that?

Thanks!

Shaft engagement, How far into the pulley is the shaft going? Do you have 1/2" of shaft in the pulley or ~2".

lg
no neat sig line

 

[Journaler]

So I took a closer look at the pulleys while running with the belt on.
It looks like the noise might be from the belt slapping the drive pulley. If you're looking from bird's eye view, as the belt rotates from drive pulley to drill, you can see the belt vibrate/wave pretty significantly. Could that be the source?

 

[wayne55]

Even if the belt looks new, they will take a "set" if left in the same position for a long time. Could try a new belt or one of the "link" belts which are supposed to prevent this "set" from happening. I use the red fenner link belt on my drill press.

 

[daveroy]

You cannot use a link belt in that DP... it is a variable speed design.