The Home Machinist!

Taking the Chinese 3 Jaw Metal Lathe chuck apart for cleaning. Really happy I did this. The chuck hadn't been as smooth as it had been and there was a lot of crap inside it. Back to its usual smoothness and a pleasure to use again. Never done it before and it proved fairly easy. If yours isn't smooth, don't hesitate to take it apart and clean it.

https://youtu.be/WK2veaUNyQ0

Nice Jim!

Thanks RSG.

As you've found Jim most lathe chucks are pretty simple. Any binding while opening or closing is a sure sign they need a cleaning. I've got a mix of 3 & 4 jaw European and far east chucks. I can't say about the Chinese one's, but the instructions for my Emco's were quite specific about making sure the scroll pinions go back in the same location each time you clean the chuck. The reason was that the master zero marked pinion was what was used to finish grind the jaws for the best concentricity. Tbh it's never seemed to make 100% logical sense, but I'm not about to second guess the chuck manufacturer. If they consider it important enough to mention then there must be some good reason behind it. A few weeks ago I watched a Haas video about properly cleaning and re-lubing a cnc power chuck and they made a point of mentioning the internal parts will have slightly different wear patterns and also wear into there location so should be placed back in that same location each time the chucks cleaned. Out of habit with my Emco's I just do the same with the Chinese chucks as well. And while those Emco's have never needed any deburring, spending an hr or so with some fine needle files and stones and deburring every surface on the Chinese chucks including the scroll & pinion teeth, scroll, the jaws and there teeth and slots etc make them much much smoother to operate and pull apart for cleaning. I've also found that polishing both the pinion slots and pinion retaining pins helps to smooth the operation out a bit more. All that gets done for you with the more costly chucks. But at the price of the off shore one's there's no money left for them to do so.

It's a standard chuck maintenance item, but for some reason not well known by the average person with a home shop that pulling chucks apart for a detailed cleaning once in awhile isn't optional. So maybe your video will help. Through drilling and boring parts obviously creates the most problems. When I remember I'll usually close the chuck jaws to just about where they grip the part and then stuff a rag or paper towel inside the chucks recess and just below where the parts rear face will be. It delays the inevitable chuck cleaning by quite a bit. Bison and maybe some others sell a "special" chuck grease. I've tried a few different automotive type greases and way oil and think a light film of the way oil works better since the grease tends to retain the chips in semi fixed locations while the oil seems to allow the chips to slide out of the way a bit better. I do know using any type of grease for lubrication seems require far more frequent chuck cleaning. I suspect but don't know for sure that the chuck grease might be a better idea if you were using flood coolant. The one issue with the oil is you'll get a slight spray of it coming out the first few times you spin the chuck up to high rpms.

Yeah, the worst is boring cast iron or cast steel where the back of the bore drops right in on the scroll. What a mess... I've tried pugging, but that usually just causes pile-up and recut problems for me.

pete wrote: ↑Wed May 29, 2019 4:41 pm ... but the instructions for my Emco's were quite specific about making sure the scroll pinions go back in the same location each time you clean the chuck. The reason was that the master zero marked pinion was what was used to finish grind the jaws for the best concentricity. Tbh it's never seemed to make 100% logical sense, but I'm not about to second guess the chuck manufacturer. If they consider it important enough to mention then there must be some good reason behind it. .....

I have often wondered what that zero mark is on my Emco chucks, interesting bit of info.

Appreciate the replies one and all, I did whip it back off today and lightly grease inside.

If you do a lot of polishing or sanding on your lathe, the gritty dust can really get into the jaws and cause the chuck to bind up. I use light oil instead of grease as well, so that the chips don't stick. I'll also run compressed air while I'm boring a hole to blow chips out of the hole (inserting my try at your own risk statement here as it does blow the chips around-wear goggles!) or through the spindle to minimize them getting into the chuck and it also helps with clearing the hole while boring so the finish is nicer.

BadDog wrote: ↑Wed May 29, 2019 5:50 pm Yeah, the worst is boring cast iron or cast steel where the back of the bore drops right in on the scroll. What a mess... I've tried pugging, but that usually just causes pile-up and recut problems for me.

Blow air into the back side of the spindle?

ctwo wrote: ↑Mon Nov 18, 2019 3:37 pm

BadDog wrote: ↑Wed May 29, 2019 5:50 pm Yeah, the worst is boring cast iron or cast steel where the back of the bore drops right in on the scroll. What a mess... I've tried pugging, but that usually just causes pile-up and recut problems for me.

Blow air into the back side of the spindle?

When I was actively engaged in machining, one of the jobs I ran (repeatedly) was making a drive for closing large doors (think partitions, like a huge door for an airplane hanger). Some of the components were made of ductile iron, which had to be bored for welding, as well as for a sintered bronze bushing. I faced the same problem, that of chips entering the scroll of my chuck. I used soft jaws to machine the components.

I solved my problem by attaching a shop vac to the back side of the spindle. Easy on my Graziano---just duct tape a triangular attachment to the gear cover. The results were exceptional. No dust in the shop, with virtually all the chips ending up in the shop vac.

I recommend against the idea of introducing air, as that will suspend all of the dust created by the cut. Won't take long before the shop is filled with graphite dust. Can't speak for others, but I don't tolerate well the dust that comes from machining gray iron (which is what ductile is made from).

H

Harold_V wrote: ↑ I solved my problem by attaching a shop vac to the back side of the spindle.

That thought occurred to me. Glad to see it validated!

Harold_V wrote: ↑Mon Nov 18, 2019 4:30 pm I solved my problem by attaching a shop vac to the back side of the spindle. Easy on my Graziano---just duct tape a triangular attachment to the gear cover. The results were exceptional. No dust in the shop, with virtually all the chips ending up in the shop vac.

I recommend against the idea of introducing air, as that will suspend all of the dust created by the cut. Won't take long before the shop is filled with graphite dust. Can't speak for others, but I don't tolerate well the dust that comes from machining gray iron (which is what ductile is made from).

H

Harold, your solution sucks

Of course, you could say mine blows

I remember now the last time I machined cast iron, I did use a shop vac and for the very reason it irritated my nose, plus I wanted to keep the abrasive bits off my lathe. There is probably little danger of sucking more dust into the chuck and spindle, but I'd probably still want it going away from the head. Maybe you can fix the hose near enough to the end of your bore, or at least that's what I've seen on youtube