Bench drill problem - advise please

[Neil G]

Hi all
I recently bought an Axminster bench drill from a deceased estate and as it looked in fantastic cosmetic condition I stupidly did not try it.
When I got home and tried it there was an immediate problem with vibration which got worse as the quill was lowered.
I hoped that it was a problem with the pulley alignment or with the belts, but after replacing the belts and aligning the pulleys. The vibration was reduced but is still apparent.
Everything points to a bet shaft but after visiting a local metal fabricators they said that the shaft is relatively straight.
I have tried to buy a new shaft from Axminster but the part is no longer available even thought the machine is less than 10 years old
I think that the machine is a clone of one sold by SIP and Jet but obviously it would be a bit of a gamble as to whether a shaft from them would either fit or cure the problem.
Any thoughts on what this problem could be?

 

[Inspector]

How much does the shaft move when measured? If it is within tolerance then spending money on a "maybe it will fit" shaft is a waste. Have you a dial indicator to check the runout?

Pete

 

[Jameshow]

Bearings gone??

 

[graham88]

Maybe a bearing has worn down. Try turning the chuck by hand, if it feels rough then bearings are a good place to start.

 

[Neil G]

Hi all - thank you for the replies!
Shaft run out was minimal at the quill end but was almost impossible to measure at the other end due to splines machined into shaft for drive.
All of the bearings seem to be in excellent condition with no discernible play.
Forgot to mention that when you wind the drill right down to the bottom and the let it go it does not return easily to the top and seems to bind up - which suggests to me that the splines end is catching on the tube it runs through.

 

[chaoticbob]

I have a floor standing JET which was almost unusable because of vibration when I got it, but I don't recall if the problem was dependent on quill extension. It turned out that the pulleys were way out of balance. Having an engineering lathe I was able to fix it myself and the machine now runs OK. Might be something to look at.
Bob.

 

[Neil G]

Chaoticbob - you may be onto something but unfortunately i don’t have a lathe.
If I can get the main pulley off (the one on the shaft) I may see if I can gig up a heath robinson way of checking the balance. I have already tried to remove this pulley, but after taking the big nut off I could not get it off the shaft.

 

[Sandyn]

You could possibly check the balance with the pulley still on the drill. Put something in the chuck and use another hand held drill to drive the shaft. It may show any out of balance.
There are often sneaky grub screws on pulleys.

 

[Sandyn]

Forgot to mention that when you wind the drill right down to the bottom and the let it go it does not return easily to the top and seems to bind up - which suggests to me that the splines end is catching on the tube it runs through

could be a broken return spring, or not tensioned properly, sometimes on old machines, the grease in the return spring goes hard.