Anyone know the weight of the knee?

[Dabbler]

Anyone got any idea what the weight of the knee including tables might be? I am guessing 500 lbs but someone might know better. Thanks if you do.

Some weights posted by another person for a Bridgeport j head mill with a larger table

These jive with my weights +/- 10% My Hartford knee is 275 lbs, and my First is a little more, at 300 lbs(but it has a bigger table, and longer Y axis).

As for reducing wear on the bevel gear, the most common wear cause is swarf that drops onto the bevel gear. cleaning it regularly and putting a soft shield (such as rubberized fabric) to prevent swarf from getting jammed in the gears is a far more valuable way to preserve the two bevel gears.

My Hartford is 45 years old, used daily in a tool and die shop, with the gears caked in steel and aluminum swarf - with a good clean, it works perfectly. And it probably will continue for another 20 years like this.

My First has a 'sorta' shield over the bevel gear, and they are brand new looking - even has some of the machining marks still on the gears. It is from about 1977-78, used every day in a production shop.

 

[pontiac428]

What sort of behavioral changes in backlash and settled parallelism would one anticipate when switching from a steady gravity-affected table elevation system to a counter-supported system? How much "positive weight" are you maintaining compared to a fully-floated system?

My sash windows settle where the pulleys and weights let them set. They don't close square and firm against the entire lower edge of the moving pane like full weight windows, they just kind of touch down on a corner and sit in balanced equilibrium. See where I'm going with this? My question is how has this difference (essentially mechanical backlash changes) been accounted for?

 

[vecair]

Interesting to think about and learn different machines. I tried to find a way, zerk or something, that let you lube the bevel gears on my ExCello, nothing. So I watched a video on disassembly of a Bridgeport knee, the bevel gears are completely open under the sliding swarf plates. This guys had plenty of swarf in them as well. I wondered if that is correct? The ExCello gears are completely enclosed in the casting, but still no way that I can find to lube them. I learn something never everyday Any comments from the BP group? ( I think I need a job!)

At the 29:22 mark if your interested.

 

[MyLilMule]

My knee probably had 5 pounds of swarf and chips in it. I put way covers on it before I started running it. Hopefully, that will keep it to a minimum. My guess is a lot of it finds its way in through the gap between the knee and the column. I've seen some that have rigged up a line on the oiler to drip on the bevel gears. I thought about doing this myself, but the thought didn't occur to me until after I reassembled it. I even have an open port on the manifold. Oh well.

 

[Dabbler]

still no way that I can find to lube them.

You can make a way: drill a hole for an oiler, copper pipe to drip on the gears. Use steel wool in the pipe to moderate the drip so it takes a while to empty the tube...