PDA

View Full Version : Help! Bridgeport Mill



Blackwaterforge
04-19-2006, 06:24 PM
Was piddling with quill feed today. Will not work now. Any advice?

JCHannum
04-19-2006, 06:42 PM
You should spray it with WD40 after piddling on it to keep it from rusting.

motorcyclemac
04-19-2006, 06:44 PM
Someone will correct me if I am wrong...(jump in guys). I seem to remember ...fuzzy memory....but I think there is a .125 yellow brass shear pin in the drive for the quill feed.

Anyone? Anyone?

-Bill

Leigh
04-19-2006, 08:20 PM
What exactly were you doing? Was the mill powered up at the time? Was the feed engaged? Did you change any levers while the feed was engaged?

motorcyclemac
04-20-2006, 03:30 AM
Your post reminds me of a related story about quill feeds.

Many...many moons ago when I was in technical college myself and another student were given the task to build a drill press. This was to be a bench mounted size press and we were to build it totally from scratch. We cast the base and the head casting from cast iron after fabricating wooden patterns. At the time I was involved in turning spindle for the press while my parter in the project was machining the holes in the base and head casting. I was totally involved in machining the spindle on each end for the bearings when I heard a sickening crunch from our brand spanking new Bridgport mill. My hide crawled from the sound and I powered my lathe off to investigate.

When we cast the base we didn't use cores for the post hole. We simply determined that it might just be easier to mill off the boss for the post and hog out the hole. So we cast it solid. My partner did a beautiful job of milling off the top of the boss and layed out the location for the thru hole. He drilled a pilot hole and then a thru hole of .500 inch. He intended to step the hole up bigger to a point where he could get it set up on a big mill and hog it out to 3.00 inches. He got a little frisky and used a step shank bit fixed in a R-8 collet. His pilot hole as I said was .500....the step shank bit was 1.25 if I recall correctly...it may have been bigger. He had the spindle speed quite slow and was using the quill feed to drive it home. He had flood coolant running and away it went. The chip load was gnarley to say the least. It shoved the bit in to the point where the cutting edge was at full engagement and the bit was loaded too hard. Poof ...wiped out one quill feed. The instructor was less than impressed at his choice of method. The instructor calmly said that if you wanna do something like that to a Bridgeport...then at least understand that the quill drive has some small gearing and is really intended for boring heads and such. If you want to drill huge holes with it..perhaps locking the quill and cranking up the knee would have been a little better! I was totally surprised by his calm attitude and understanding. In light of the fact that the mill was stinking new...still smelled like fresh paint...and the motor had the "new motor smell". I belive it was about 4 days in service.

Not to say this is related to your cause of non functioning quill issues...but it was the story that made me think that there was a shear pin in the drive. In spite of the fact that I wasn't the poor booger that broke the mill...I have to this day treated quill feeds with a gentle hand. I have related that story to just about everyone I know that owns / operates a Bridgeport or clone mill. Simply in hopes that nobody has to hear that icky busted brand new mill sound. Ewww.


Cheers
Bill

SJorgensen
04-20-2006, 04:23 AM
Thanks for that quill drive story Bill. I'll put that in my knee method in my bag of tricks. My BP series 1 Rigid Ram might be a bit stronger than some others but I'd rather not risk ever hearing that haunting noise.

Spence

WJHartson
04-20-2006, 04:25 AM
Think we need to know a little more about what you were doing and what is not working. Do you know how it is suppost to work? Will the feed work manually up and down when you turn the Handwheel? What is the position of the center pin in the handwheel, in - out -center? Let us know what you did and we can probably help.

Joe

kap pullen
04-20-2006, 06:52 AM
Was the feed working when you started "fiddling" with it?

I heard a saying once that went like this;

"If it ain't broke, don't fix it"

Kap

Blackwaterforge
04-20-2006, 09:13 AM
I was useing annular cutters to bore 9/16 holes in 11gauge tubing. Quill feed
wasn't locking in correctly. Sometimes would trip out with light pressure. Other times would not trip at all. Removed plunger, handwheel and housing that holds clutch lever. Cleaned, buffed plunger, reassembeld. Everything seems to work properly. Handwheel functions correctly in nuetral, upfeed and downfeed. But, quill dosn't feed when it's engauged?

WJHartson
04-20-2006, 11:01 AM
Will the quill feed lever for in and out move easily from one position to the other? Will the lever to change the feed rate move to each position? Will the clutch handle stay in the the IN position when moved toward the spindle?

Joe

Blackwaterforge
04-20-2006, 11:29 AM
Thank you for the quick response! Yes everything functions normaly. It even sounds like it's engauged while running. But it dosn't feed the quill and the sensetive feed handle dosn't advance. The handwheel dose turn clockwise, counterclockwise and shift into nuetral.

pcarpenter
04-20-2006, 11:45 AM
Having had my Bridgeport apart for most of a year for complete cleaning and rebuilding has had some advantages. You get a chance to become very familiar with just how things work when all the parts are laid out in front of you. :o

In simplest form, most of what is in the basic lower head assembly is in some way related to quill feed. From a control standpoint, there are three important levers and sub-functions:

1. Feed drive engagement lever (high and on the right of the head) which allows power to be applied to the rest of the works. If you don't hear any movement in the gears, inspect this assembly (which means head disassembly). Of course, make sure it is actually engaged, with the pin in one of the two appropriate locations and not stuck in one of the cap screw heads that hold the assembly in place:D This looks to me like a common source of a problem...easily fixed. Unfortunately, I don't remember a *brass* pin here.

2. Feed *rate* change lever assembly. Left side, three positions. Decides *which* gear is engaged. First make sure you have the pin in one of the three defined positions and not stuck in one of the cap screw heads that holds it as above. I am not sure that is a possible scenario with this selector as with the one above, but thought I would mention it.

3. Feed trip lever and clutch assembly. This is usually most suspect when things just won't stay engaged. Think of it as an adjustable trigger and sear arrangment for engagement and disengagement. Additionally there is a clutch assembly to prevent disasters. There is a pin (brass, maybe?) here, and more importantly, a toothed clutch that is supposed to be adjusted under spring tension to slip *before* anything would really break. If this clutch slips you hear the horrible sound described before as teeth slip past teeth. Still, this is the sound of absolute disaster being averted and not the sound of part death unless you keep letting it slip.

Here is a site for manual downloads.

http://www.bbssystem.com/viewtopic.php?t=62

Good luck!
Paul

WJHartson
04-20-2006, 02:08 PM
Paul has given you a lot of good information. If the hand wheel won't move the quill up or down manually when you move the center pin in - center or out it won't be driven when the auto quill drive is engaged. Make sure that it is moving properly.

Joe