POTD- PROJECT OF THE DAY: What Did You Make In Your Shop Today?

[NCjeeper]

Well one step forward and one step back. I got the big Jet lathe under power finally. Nice to see it finally run. Unfortunately, there was a noise coming from the back of the headstock. I think I have tracked it down. The drive pulley that turns the input shaft into the headstock was loose. After taking off the belts and removing the pulley I found some issues. The retaining nut had backed off or was not tight enough, and this allowed the pulley to back off the tapered shaft and wobble around. Prolonged use like this damaged the taper in the pulley and the keyway. So looks like the fix is going to be to bore out the pulley bore. Then sleeve it and cut the taper in it. Then cut the keyway. So what do you think the best material is to use to sleeve it with? The pulley is cast iron. I was thinking bronze.

 

[woodchucker]

how's the shaft look?
It really won't matter what material. it is a non-moving fixed part. if it was a moving part, bronze. With the expense of bronze, any handy metal will work, just glue it in with loctite or press fit it in.

 

[extropic]

Well one step forward and one step back. I got the big Jet lathe under power finally. Nice to see it finally run. Unfortunately, there was a noise coming from the back of the headstock. I think I have tracked it down. The drive pulley that turns the input shaft into the headstock was loose. After taking off the belts and removing the pulley I found some issues. The retaining nut had backed off or was not tight enough, and this allowed the pulley to back off the tapered shaft and wobble around. Prolonged use like this damaged the taper in the pulley and the keyway. So looks like the fix is going to be to bore out the pulley bore. Then sleeve it and cut the taper in it. Then cut the keyway. So what do you think the best material is to use to sleeve it with? The pulley is cast iron. I was thinking bronze.

Yes, how did the shaft survive?

The material is important. Unless you can guarantee that the axial compression from the retaining nut will always (100%) be sufficient to prevent torque from spinning the pully (in which case you don't need a key at all, HaHa), make the sleeve from at least CRS. Can't you buy an OEM replacement pully? OEM replacement should insure correct taper and you don't have to mess with it.

Add torqueing that nut to your Preventative Maintenance list.

If you make a sleeve, I recommend press fit and putting a Dutch key or two in.

Dutch key: best explanation I could quickly find. Pins are as good as screws for permanent assemblies.

Different type of shaft key (Dutch Key) - HomemadeTools.net

Hi All This is the method I have used on several projects to lock a nut to a piece of studding or a plain collar to a shaft (If placed at the end of a

www.homemadetools.net

 

[NCjeeper]

I can look around, but the lathe is from 1980 so I don't think I am going to locate another pulley. CRS sounds good. Another machinist just mentioned the same thing.

 

[woodchucker]

I would just make a plug. The dutch key is a good idea too. I would go with a set screw, not a pin. That way you can remove it if needed.
I don't like just installing a screw and cutting it off if I can avoid it. Also the threads lock it in so it can't come out of the sheave. So it does the job two ways... win, win.

 

[erikmannie]

Why use hex bolts instead of like low head cap screws? Im just curious.

When I first designed this project in my head, I did not realize that the top surface needed to be flush. I bought Grade 8 bolts & washers.

Later, while I was actively working on the project, I went to the local hardware store, but their “flush profile” hardware only went up to 1/4”.

 

[AGCB97]

The drive pulley that turns the input shaft into the headstock was loose. After taking off the belts and removing the pulley I found some issues. The retaining nut had backed off or was not tight enough, and this allowed the pulley to back off the tapered shaft and wobble around. Prolonged use like this damaged the taper in the pulley and the keyway.

I would just try cleaning both pieces with a file, Loktite in a new key and give it a try. If runout and wobble are OK, then you're done except for a vigilant eye on it for a while. If not, then proceed with a more aggressive rebuild. It's only a pulley.
Aaron

 

[wachuko]

Judge away for taking shortcuts... I learned the correct way, well, several correct ways, for making these. Thanks to the folks here. But did I try to do them that way... nope. I have several more that I need to make and will give it a try later. For now, I just wanted this finished.

Two 5/16"x5" bolts would do for now... a little bit of time on the lathe and voila... handles. I will finish them off when I get to Orlando.





The other thing I was not paying attention is my sweat falling on the chuck... son of a gun... I sweat just thinking about it... and as I have learned from you folks, blood and sweat are no good for the machines...



Took a 3M pad and tried cleaning it... apply some way oil... but already stained for life...

 

[mmcmdl]

blood and sweat are no good for the machines...

Nor tears . Run it like you stole it !

 

[wachuko]

Nor tears...

I will try to hold those back. I just get so emotional when I finish making a part.... and I have not even tried using the parting tool...