Bridgeport Power Feed

Discussion on all milling machines vertical & horizontal, including but not limited to Bridgeports, Hardinge, South Bend, Clausing, Van Norman, including imports.

Moderators: GlennW, Harold_V

Post Reply
azscj
Posts: 29
Joined: Mon Aug 13, 2012 9:04 pm
Location: Phoenix AZ

Bridgeport Power Feed

Post by azscj »

I came across one of these this week....didnt realize Bridgeport made these in the past. Anyone have one of these? Good experience? Bad experience? I would rather buy one of these used than the current China made ones I see sold thru most outlets.....unless I hear otherwise. Thanks for input.

Image
User avatar
SteveHGraham
Posts: 7788
Joined: Sat Jan 17, 2009 7:55 pm
Location: Florida

Re: Bridgeport Power Feed

Post by SteveHGraham »

This won't be helpful to you, but I like the speed gradation. I always wondered how I was supposed to figure out my x speed. Maybe I can find a way to create a gradation for my Asian feed.
Every hard-fried egg began life sunny-side up.
John Evans
Posts: 2366
Joined: Tue Jan 20, 2009 9:33 pm
Location: Phoenix ,AZ

Re: Bridgeport Power Feed

Post by John Evans »

I have one on one of my BP's works fine . BUT will not bolt up directly like the Servo clones ,lead screw is shorter. Going the other way replacing that with a Servo style you can get a lead screw extension kit.
John
www.chaski.com
Carm
Posts: 457
Joined: Fri Jan 18, 2008 5:14 am

Re: Bridgeport Power Feed

Post by Carm »

"Anyone have one of these? Good experience? Bad experience?"

Mine was made mid 80's. Good experience so far.
I have heard once you have trouble, they're done.
Snagged a Servo from a friend who went CNC so I have a backup.

Steve
Not hard to calibrate with a scale and a stopwatch.
I recall they are not closely repeatable, but fine for B'port style work.
User avatar
Harold_V
Posts: 20231
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: Bridgeport Power Feed

Post by Harold_V »

Carm wrote: I have heard once you have trouble, they're done.
Not necessarily true. The board in mine failed years ago, but I was able to make an exchange for one that had been serviced. Unfortunately, the company involved is no longer (Seattle, Washington). I seem to recall it cost me about $100. Worth the expenditure, for sure.

I've been well satisfied with mine.

Steve---speed is selected based on performance. If you don't have a clue where to start, start slow and increase until you achieve the cut you desire.

Harold

Edited to make clear what failed.
Wise people talk because they have something to say. Fools talk because they have to say something.
WJH
Posts: 1417
Joined: Sat Jan 16, 2010 9:29 pm
Location: Florida

Re: Bridgeport Power Feed

Post by WJH »

I have the very early power feed, it works, but I am not buying another vfd just to use it. I am more concerned about the weight of it causing table sag. I leave my Bridgeport with the power feed cranked close to the knee.
User avatar
Harold_V
Posts: 20231
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: Bridgeport Power Feed

Post by Harold_V »

WJH wrote:I am more concerned about the weight of it causing table sag. I leave my Bridgeport with the power feed cranked close to the knee.
No harm in doing so, but the idea of the feed causing sag is unfounded. The tensile strength of cast iron exceeds by an unfathomable margin, the weight of the drive.

Bridgeport tables sag because of internal stresses, not because of weight. Because the top surface is fully machined, unlike the bottom surface, it releases stresses more than the bottom of the table, thus the eventual bowing. If the castings were properly aged or heat treated, it wouldn't be an issue. Considering the relatively low price of a Bridgeport (they are not a great machine), that's expecting far more than money can buy.

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.
spro
Posts: 8016
Joined: Mon Feb 20, 2006 11:04 pm
Location: mid atlantic

Re: Bridgeport Power Feed

Post by spro »

I think the "sag" is caused by the unequal weight in this case. It is more wear to the right side than the left. It appears as sag in a conversation but is the weight of the earliest gear shift power feeds. Even I don't think cast iron "sags". I was disabused of that notion long ago.
This gets into another truth you mentioned about the table curing at a different rate and changing by the production milling done on the top compared to the bottom. The effect to the table surface by a heavier table feed unit, would balance it out if it was equal at both sides but it isn't.
I deleted before posting anything about tying one generated motor phase to another because I cannot edit or delete.
azscj
Posts: 29
Joined: Mon Aug 13, 2012 9:04 pm
Location: Phoenix AZ

Re: Bridgeport Power Feed

Post by azscj »

Going back to John Evans comment....these units are not a direct bolt in place unit. I see that now. You actually have to change the lead screw. So there is a hidden cost involved with this that looks to be about $200 to $300 additional to do that. So I will need to rethink if I want to go thru all that effort as much as I would love to have a unit that says "Bridgeport" on it....
Post Reply