Mill head, rebuild.

[Mcdavis86]

I got a lagun FTV-2s that’s a pretty tight machine, however the head is making some racket. To anyone with some experience in these heads does that noise jump out as something specific or will I have to completely tear down to diagnose. Drawbar is out of it, video posted below.

 

[Martin W]

Hard to tell from the video, and I’m sure you checked but almost sounds like a pulley rubbing on sheet metal?

 

[Mcdavis86]

I really haven’t very good

 

[Mcdavis86]

Hard to tell from the video, and I’m sure you checked but almost sounds like a pulley rubbing on sheet metal?

I really haven’t very good, I peeked in the vents that come off the side and nothing looked like it was. Not to say it isn’t though. I wonder if I could take that all the vents off and that front cover that the speed indicator is on and see more?

 

[pontiac428]

The vents will let you see some, but you'll see all that you can see from just pulling one vent. The video you posted must not have captured the sound, I can just hear it climbing as you dial the speed up with maybe a little bit of a clicky sound coming from the belt maybe- that's with headphones on. No bull gear clatter or bearing noise from what I can tell. Does the noise change if you drag the brake a little? Have you put it in low and pumped a few squirts of grease in the rear fitting while running? I have a FTV-2 manual on pdf with kind of funky OCR (it's worth 85% of the real thing) that I can send if you need it.

 

[markba633csi]

Being a vari-speed head there is more to go wrong than the step pulley types- there is a Reeves drive in there
and the mechanism wears over time. Belt is probably worn too.

 

[matthewsx]

Probably comes down to how badly do you want to rebuild it. Some guys need to have everything perfect while others are happy if it does it's job well enough. I'm in the later camp and won't be rebuilding my vari-speed head until absolutely necessary.

John

 

[RaisedByWolves]

I would be more than happy with a machine that quiet.

We have two noisy BP mills at work, one sounds like an outboard boat motor with loose rod bearings and the other sounds just like the first one with a hand full of gravel thrown in it.

 

[coolidge]

I have a mill head like this stripped bare on my bench right now. Here are some points of wear to inspect...

First, the 2 variable pulley halves that slide up/down (the other halves are fixed). There's one on the motor shaft and another on the spindle pulley hub. The common (very) wear points for these pulley halves are the shaft keys which are made of brass or even plastic and get chewed up by the steel shafts. The other are the oil-less bushings inside the pulley bore they slide up/down on which can be a PTFE impregnated metal shell or even a plastic bushing. These simply wear out and your pulleys get all sloppy and wobbly.

Second, the spindle pulley hub and the spindle gear hub. These mesh together when you shift the mill into high speed range. As you shift into high speed range what's happening is the shift lever is raising the spindle gear hub up, into the spindle pulley hub. Each hub has wedge shaped teeth that mesh together so the closer they come together the tighter they mesh until there's no slop at all. These teeth wear and on most heads there's an adjustment to tighten them as they wear. Eventually they wear to the point that the hub teeth bottom out in each other then it's game over and time for new hubs.

It could be other things like bearings, but the above two wear issues are far more common so I'd start by inspecting those first. If they require repair (they are wear parts that need replacing at some point, like belts) I wouldn't let it slide or other parts of the head will begin to self destruct.

 

[matthewsx]

I have a mill head like this stripped bare on my bench right now. Here are some points of wear to inspect...

First, the 2 variable pulley halves that slide up/down (the other halves are fixed). There's one on the motor shaft and another on the spindle pulley hub. The common (very) wear points for these pulley halves are the shaft keys which are made of brass or even plastic and get chewed up by the steel shafts. The other are the oil-less bushings inside the pulley bore they slide up/down on which can be a PTFE impregnated metal shell or even a plastic bushing. These simply wear out and your pulleys get all sloppy and wobbly.

Second, the spindle pulley hub and the spindle gear hub. These mesh together when you shift the mill into high speed range. As you shift into high speed range what's happening is the shift lever is raising the spindle gear hub up, into the spindle pulley hub. Each hub has wedge shaped teeth that mesh together so the closer they come together the tighter they mesh until there's no slop at all. These teeth wear and on most heads there's an adjustment to tighten them as they wear. Eventually they wear to the point that the hub teeth bottom out in each other then it's game over and time for new hubs.

It could be other things like bearings, but the above two wear issues are far more common so I'd start by inspecting those first. If they require repair (they are wear parts that need replacing at some point, like belts) I wouldn't let it slide or other parts of the head will begin to self destruct.

Following your rebuild on the other thread.

Definitely need a tight, reliable head on that CNC machine, sounds like you've got big plans for it. With my hobby machine I'll be lucky to get a few dozen hours a year so not too worried about things self destructing anytime soon. If it happens I'll tear it down then and either repair or find a replacement step pulley head. Or, go to a direct drive system like you were contemplating.

Like yours, mine is an off brand that may not correspond exactly to the Bridgeport model.

I'd definitely be interested in finding the spindle gear hub adjustment on mine to see if that's what's keeping me from getting to top speed, any tips on where to begin with that?

John