Don't forget to listen when your machines talk to you

[9fingers]

The last time I run some timber through the thicknesser, it made a strange groaning noise when I switched it off. Tried again and more groans.
Yesterday I decided to investigate. One of the drive chains was really tight on the tension side and all the slack on the other.
The tight side was tuned to middle C or higher.
I removed the chains to find the outfeed roller could not be turned by hand. I remover the roller and one bearing (plain shaft in a hardened steel block) was absolutely solid. With the block in the vice, i needed a 14" stillson wrench to get the roller to move. It was stuck like a stuck thing.
Manged to get a little penetrating fluid into it but still dead tight. So I put it back on the machine and ran the motor to turn it whilst I added light oil. Still groaning at switch off. Then I notice the shaft was too hot to hold!

Left it over night whilst I thought about solutions and this morning initially it did not groan but soon warmed up enough to complain.

Removed it once and applied controlled force with a bearing puller and eventually it gave in. The shaft had areas of burnt oil that came off with solvents and thankfully very little scoring. I polished off the high spots and the bearing block fitted quite nicely.
All back together and mechanism oiled and running sweetly again.

It could have turned out quite nasty if it had been left and spare parts are unobtainable.

So do listen when your machines talk to you and sort the problem out pronto. They rarely go away by themselves.

Bob

 

[CHJ]

Much longer and you could have had the roller shaft friction welded in the bearing block.

 

[9fingers]

Yes it was a narrow escape from having to machine off the bearing block and make a new one! Spares for this Delta 380 are from unobtainium.

 

[Lons]

Good advice Bob.

Years ago in the middle of a sizeable project for a customer I found the rise and fall mechanism of my table saw becoming increasingly stiff. I sprayed in some light oil but it made little difference, Hobson's choice I was on a deadline and kept going until the worm drive shaft stripped. Luckily I finished the job but it was a day and a half's awkward work to strip down and replace the shaft and would have been a nightmare had the parts been unavailable.

 

[Mike G]

Zen and the Art of Motorcycle Maintenance. Bob Persig.

 

[Trevanion]

Learning when things "don't sound quite right" is a very important part of working with machinery in general, of course, you've got to have enough experience to know what sounding right is and isn't.

I remember my D.T. teacher telling the class "I know every sound in this workshop, so I know exactly when something is going wrong or if you're messing about".