Supermax YCM-16VS Knocking Noise in Head

[FloppyDisk]

Max Ain't Feeling Well

I'm a noob and I have a 1988 Supermax YCM-16VS w/ an Anilam Crusader M controller that I bought 'new' in April this year. Took me months to get power, 3 phase converter, etc. to be able to power up and get running. I have been able to scare up manuals, some from Tim Podgwaite (thank you sir!) regarding the Crusader M and one from YCM on the mechanics. If anyone needs a manual, I can fwd...

Was ready to start making chips last weekend, turned on the spindle and I heard a nasty knocking noise. The spindle had seemed to work without the knocking noise the 2-3 times I had it on before. I had a machinist from work over to check out the machine (before the knocking noise) and we ran it a good 10 minutes w/ out any issues. But, we did fiddle w/ the power draw bar and had issues making it work. I replaced the air lines, regulator and other pieces w/ new and it seems to work better. But, now I have the knocking noise...

I have uploaded a video to youtube w/ some of the things that I tried and you can hear the knocking: Max Not Feeling Well - YouTube
One machinist at work suggested I try running it in neutral.

Last night, I worked the Hi - N- Lo lever in an effort to see if it was 'out of gear' and see if I could eliminate the knocking. Since any access into the head involves removing the motor, I have removed the assembly Cover just beneath the motor to have access to the drive belt, motor shaft and motor pulley. In N, I could manually spin the spindle and then spin the motor shaft and the knocking noise would go away and then come back and then go away, etc. as I rotated the 3 HP motor drive shaft. Very strange. Seems to validate that the knocking noise would happen on HI and then not.

Some Observations
It seems to knock in low - nearly always. Although, I didn't power up last night.
Per the video, I knocked in H, but then it didn't. I did see that as well w/ my manual test last night.

Next steps?
I could certainly use some help here. One suggestion was to remove the Lo- N - Hi switch and re-insert it to see if there is some issue w/ that. But, it seems that the issue is with the gearing and I'm thinking that a gear is not engaging or outright broken. Removing the Lo-N-Hi switch may not be the issue.

As far as opening the head, the manual shows 2-3 areas to break it. I think it the two best options are the procedures for the DRIVE BELT REPLACEMENT or the TIMING BELT REPLACEMENT. Since I think it has to do with gearing, I'm voting for TIMING BELT REPLACEMENT and access to the gears. I've included the page out of the manual.

I tried to upload attachments (manual pages) to this posting, but practicalmachinist was not cooperating so I uploaded them here: Max Not Feeling Well

Any help someone can provide would be much appreciated!
Thanks,
Mark

 

[Pat G]

Well it sounds fine in Hi so your spindle and motor is probably OK. I would guess what ever mechanism engages LO is hanging up. Maybe junky grease sticking and lack of lubrication to make it happen.

I think I would take her apart, and clean it up. Lube it and put it back together. The problem will probably expose itself.

 

[FloppyDisk]

The Dr. has scheduled Surgery for Max...

Thanks for the feedback. That's what I was thinking as well. I plan to get started on her later this afternoon.

Let's just say the wife wasn't too excited the day Max showed up and this doesn't do much to make her and Max get along any better.

I'm still leaning towards looking at the timing belt area - any suggestions?

Thanks,
Mark

PS I tried to upload the files (again) and this time i got window that allowed me to upload, but the filesize max was 19.5kb. Maybe those limits were set when DOS was the main operating system???

 

[tdeutmeyer]

Is the power drawbar making the noise?

 

[FloppyDisk]

Surgery in progress

Thanks for the question, any help is much appreciated!

No - I don't think the drawbar is making noise. It has a KURT power draw bar and I have taken it off and pulled out the draw bar and inspected it. The spline teeth and length of the drawbar look to be in good condition, as well as the threads. Also, before I took off the spindle motor, timing belt drive box and gear box, I had pulled out the draw bar and could spin the motor manually and hear the knocking noise. So, I think that eliminates anything w/ the drawbar. One thing I didn't do at this stage was drive the quill down and spin it manually. That leads me to think I had the quill to high??

I took the gearbox off and opened it up to visually inspect everything and there doesn't seem to be anything wrong. I did have some chip/smashed metal in the drive shaft area that concerns me, but that is the only spot. The belts are all in great condition and the gears and lubrication look fine. I'll clean off the gears and I'm thinking the drive shaft was too high and might have hit the top of the speed adjustment area?? The mill is new to me and there are 2 red tape lines on the quill w/ out any markers. In talking w/ my shop at work, we think that one might be a tool change position and one a 'home' or high Z position. Either way, I think it says don't go too high w/ the Quill and run it.

I will do some cleaning tonight and tomorrow and put it back together and see what we have.

Mark

 

[TylerP]

Look for little brass filings in the case under the vari-drive disc at the motor end.

I had a YCM-40, which was more abused than any mill I've ever seen. Any how, the bronze bushing on the vari-drive disc was completely shot. Sometimes the head would be really, really loud and other times not so bad. Did not seem to be speed related.

Took the whole thing apart, made a new bronze bushing, and she was much better.

Also, if you suspect the draw bar is making noise, just take it out and run the spindle with it removed.

 

[FloppyDisk]

Surgery Protocol

I'll go look again for shavings and check out the bushings as best I can. Thanks for the suggestion.

That has been a big question of mine because I have found shavings or debris (metal) in 2 areas.

One area was 'free' in the drive belt area and I can't see where they came from. There is a slight opening on the front of the head near the speed change dial and I'm thinking over years a few shavings got sprayed there from blowing off parts. The mill was filthy when I got it with shavings everywhere, so I wouldn't discount it. But, I did find some very thin, light shavings that I was concerned about. Those shavings seemed too clean and not as shiny as aluminum w/ cutting gunk left on it. Felt like brass might be a good choice...

Also, I mentioned the 'harder' shavings around the 'splined' drive shaft. That is a concern.

Otherwise, it looks really good. I'm sure the mill was abused as well, but a machinist from work was surprised how well it cleaned up. I just want to get it so I cut parts.

 

[TylerP]

You'll need to take the belt off to check the vari-disc as the tension keeps it tight against the shaft.

Once you get the belt off, just try rocking the movable disc half and see how much play there is. Really it should be a slip fit with minimal slop, but it is just a bushing so *some* play is tolerable. You'll figure it out.

Mine had chips all over the machine, compressed air was used to clean it. However, the bronze chips were more like fine shavings and just too clean to be from a machining operation down below.

 

[alphonso]

TylerP has the answer. The bushing on one of the variable pulleys(floating side) is bad. I have a YCM 30 that had that problem on the motor pulley. Made a new bushing and drilled a grease hole from the end of the shaft so we can grease it. Been working for 18+ years.

 

[FloppyDisk]

I will look at the pulleys tonight. I recall the motor side seemed good, but not sure about the drive side. Mark

 

[IAMATT]

Open the door and let that little chinaman out! He's a spy!