VS drill press problem

[Rick Potter]

I have a 16 year old Delta 16 1/2" VS drill press, model 17-925. If I run it up to a high speed it sometimes gets the belt stuck in the front reeves pulley, and it stops dead.

I can find nothing out of order, and suspect the belt has stretched a bit, and the slack is wobbling till it gets caught in the pulley. As you run up the speed, there is a vibration at certain points, and as you go higher it smooth's out then vibrates, till it grabs at about 2500RPM. The small belt turning the rear pulley is tight, and does not slip.

I have the manual which says nothing about adjusting the big belt. The small one off the motor is self explanatory, and I am wondering if adjusting the motor also pulls the rear pulley tighter? The big belt is in good shape, as are the pulleys, and everything is lubricated per the manual.

I find nothing of value on the internet. Does anyone have experience with this model.

PS: There is no type # on the machine. Just 17-925, built in 1999, bought in 2000.

Thanks,
Rick

[Charles Taylor]

I have a Rockwell/Delta press three times as old as yours but of similar design. Mine has the original belt, which shows no sign of stretching, but that isn't saying much because your belt and mine most likely came from different suppliers and/or were made in different places. To check out whether yours has stretched--or possibly lost flexibility--would require getting your hands on a new one and comparing them.

For anyone unfamiliar with this mechanism...when you move the dial to increase RPM, it releases pressure on the underside of the front Reeves pulley, which allows the lower sheave to move down and further away from the upper sheave, and the belt to ride further toward the inside of the pulley, and the spring-loaded rear pulley self-adjusts to compensate. The ratio of the radii the belt is riding on these pulleys changes, and thus the speed.

I'm guessing, and only guessing, that the front pulley is able to move wide enough that the belt is riding on the hub or very close to it, and either the belt becomes too loose to drive the front pulley and the spindle, or the radius becomes too small/quarters too tight so the belt binds and at least some of the drive mechanism comes to a stop. How much of it stops? Everything including the motor? Just the front Reeves pulley? The belt? Both Reeves pulleys? What do you have to do to get it running again?

There is a bolt and lock nut on the underside of the front pulley that limits the widest opening of the pulley and therefore the maximum speed. (See pic.) 19-925 Detail.png If you suspect the front pulley is opening wider than it should, you can loosen the lock nut, adjust the bolt upwards a bit, and re-tighten the lock nut. (Have the dial set to the lower end of the speed range when you do this.)

I doubt that adjusting the motor will also tighten the rear Reeves pulley, but I'm saying that based on looking at the parts diagram. On my older press, the rear Reeves pulley is on the motor shaft itself. However, if the motor on your press still runs but the Reeves pulleys do not, then the smaller belt is slipping and adjusting the motor mounting may help.

[Mike Hollingsworth]

I paid about $950 for one of those in 2001. Ended up giving it away (POS) after I found a used Delta 16-665 from the sixties.

[John McClanahan]

As Charles said, it sounds like an adjustment issue. I have a Powermatic with a similar pulley setup. It has some adjustments to prevent that.

John

[Rick Potter]

I suspect Charles may be on the right track. My machine has the front pulley mounted on the spindle, with the rear pulley towards the rear of the machine, with a short drive belt to the 3/4 HP motor.

When it binds up, it is all done in the front pulley, and it stops the machine, motor and all, dead, and I am frantically hitting the off button, as quickly as possible, as the motor wants to go, but can't. It has never tripped any reset or breaker. The belt is squeezed tightly inside the front pulley when this happens, and I put a large bolt in the chuck, and use a ratchet to go back and forth until it releases.

I will check that nut and bolt Charles refers to. There is also a large nut on top of the front pulley, which might do what Charles is suggesting, and I will study the parts diagram to see if I can figure it out. It probably just allows removal of the pulley. My manual is very basic, and does not even have a trouble shooting section.

Like Mike mentions, this is a Taiwan machine, and came with a not so good chuck. It has always vibrated more than it should at certain RPM's, but it's done well for me.

Thanks for the answers guys.