Feeling "feedback" in BP quill feed

nstiesi · May 30, 2018

My 1972 series I is running well. I tore down and rebuilt it myself, including the j head. One thing I can't figure, is the feedback I feel in the quill feed handle. I only feel it when the spindle is turning. When off, the quill feed is silky smooth.

The feedback seems to vary with rpm. It just feels like the slight resistive force in the handle that is rhythmic with rpm. It doesn't seem to matter if I'm feeding in or out.

The quill power feed worm is disengaged. The power feed, when engaged, work just fine, forward and reverse, and the trip levers work fine.

Is this normal? I'm new to Bridgeports and machining in general.

Thanks!

Sent from my Moto G (4) using Tapatalk

JRIowa · May 31, 2018

I wish you hobby guys would leave off the "Series I". That doesn't mean crap! When you're talking about heads, you have a J or a 2J.

I'm guessing that the splined section of the quill has a slight bend or bow in it. Might not be much, but enough to make it move harder under power. I'll guess that the higher the RPM, the harder it is to move.

Just another thought, are you running an extra long draw-bar? Does the draw-bar stick up more than 2" from the top of the head?
JR

jhruska · May 31, 2018

Drawbar needs to be straight.
It usually has a stepped sleeve to keep the heavy hex central in the bore.
Test, pull the drawbar and collet and run it.

Vibration Hi and Lo range or just Hi?
Lo may be too slow to notice.
Occurs at 500 rpm or at another rpm?

Ever stall the mill? Creates a flat spot on the belt that is a vibration-knock.
Has the belt ever been replaced?
Were the sleeve bushings replaced at rebuild?

Does the bearing in the top of the housing-top of the cover, get hot when running after running 10-20 minutes? Hot to the touch-adjacent area.

Never had a bent-bowed splined shaft. Doesn't mean it won't happen, if you run it over with the fork truck

John

Search

Largest Manufacturing Technology Community on the Web

Search

Feeling "feedback" in BP quill feed

nstiesi

Plastic

JRIowa

Diamond

jhruska

Titanium

Similar threads