What's new
What's new

Series 60 Behind The Apron, aka "The Undercarriage"

greasysmitty

Plastic
Joined
Jan 14, 2013
Location
Seattle, WA
I pulled the apron on my series 60 to changeout oil metering units, clean and inspect. One thing that's been bugging me is that the binder clamp for the carriage doesn't seem to function, so I wanted to check that out. After pulling the apron I operated the carriage feed handwheel and saw good oil flow through the feed port up to the top galleries. Blocked it with my finger and felt plenty of pressure too, so that's good.

On the binder clamp I'm a bit mystified. I'm attaching pics to explain. The binder clamp appears to have worn so that it can't clamp down on the way; it bottoms out against the carriage before it ever clamps against the bottom of the way. I don't see how it really could have worn; it shouldn't really be a "wear" part - unless it was left somewhat tight and then continuously dragged around by the carriage (and careless operators)? So if I'm going to fix this I'll need to clearance the flat on the clamp that is currently bottoming, allowing the clamping bolt to pull it "tighter" against the bottom of the V-way. I guess my question is - there is no strict reason that this flat would be there at such a close clearance, unless Monarch intended this to perhaps be a progressive guard to prevent over tightening (and eventually fracturing) the cast iron clamp? If you left a few thou clearance, you could limit the clamping force to some maximum, encountered when the clamp flexed enough to close the clearance and bottomed out on the carriage. Seems plausible, but wear in the carriage ways would inevitably reduce this clamping force over time, which seems like not so durable of a design. Were they just assuming that a significantly worn machine would be torn down enough to readjust the binder clamp anyway? Does anyone have a good sense for how their binder clamp engages, eg is there a close clearance with the carriage on clamping, or no chance of bottoming under a clamping load?

For reference on the left hand front carriage hold down clamp I have 0.004" of clearance to the bottom of the V-way. To me this says that this is the most that the bed ways + carriage ways could have worn down since last rebuild (whenever that hold down clamp was bolted down) is 0.004 minus whatever the initial minimum clearance was, which is encouraging. This is sound logic, right? I should run across the full bed travel to a minimally worn section and see how it changes...

The hold down clamp removed and cleaned to inspect:
IMG_3603.jpg

Hold down clamp installed. 0.004" clearance under V-way:
IMG_3604.jpg

General arrangement of clamps under the front of the carriage:
IMG_3606.jpg

The binder clamp. How much do I need to clearance the contact point in the mid-span of the clamp?
IMG_3607.jpg
 
I don't see how it really could have worn;

Saddle is worn, not the little pieces. In other words, the entire apron is lower than it was before the saddle was worn

Monarch's intent was for the soft saddle to wear, with very little bed wear on the hardened and ground ways
 
I'd try and get it to clear the ledge by .010, so you could nibble at it or get under there with some feeler gages and make a single scientific cut.

Thanks for that suggestion, I'm thinking I'll try something like that. I'll report back on what I find... should be able to do a half baked determination of clamping load/torque vs displacement/clearance and figure out how much extra wear clearance to throw in there.
 








 
Back
Top