I am updating a late 50's style Bridgeport power feed. Does anyone has a brand recommendation to help weed through the tons of units out there. The unit is for home use and limited use at that. I'm looking for cheap and only need decent quality and durability.
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Bridgeport power feed retrofit.
- Thread starter NITRO702
- Start date
- Replies 12
- Views 3,218
moonlight machine
Diamond
- Joined
- Nov 19, 2007
- Location
- marysville ohio
Spend the money on a Servo, it will be trouble free for years. Spend half as much and get junk.
rons
Diamond
- Joined
- Mar 5, 2009
- Location
- California, USA
A contradiction of terms.
ignator
Cast Iron
- Joined
- Oct 8, 2012
- Location
- Marion, Iowa
My first power feed was a Servo brand on my Wells-Index. It had the custom casting to fit the right side of the table, where the factory feed unit gear box housing is, so it looks like an OEM install.
However, I've had problems with the Servo randomly going to a high feed rate, and have broken several end mills. I'm suspecting the feed rate potentiometer.
I've also installed low cost Align brand and Central Machine units for the cross and knee feeds, and have not had a single problem with them.
I've opened these 'cheap' units up, and have not seen any packaging issues. They did a good job copying some design. The only issue I've seen is the limit switch assembly, not with the snap action switches but the mechanism that trips them internally.
However, I've had problems with the Servo randomly going to a high feed rate, and have broken several end mills. I'm suspecting the feed rate potentiometer.
I've also installed low cost Align brand and Central Machine units for the cross and knee feeds, and have not had a single problem with them.
I've opened these 'cheap' units up, and have not seen any packaging issues. They did a good job copying some design. The only issue I've seen is the limit switch assembly, not with the snap action switches but the mechanism that trips them internally.
HWElecRepair
Hot Rolled
- Joined
- Dec 9, 2013
- Location
- Fort Wayne, IN
@Ignator Rarely do the pots go bad on those. If the speed randomly shoots up to a high speed/rapid, I would look at damage on the armature or a cap on the circuit board is going. If it is a 140, I would take the circuit board out and heck to make sure all of the solder runs are good. I have seen it happen alot where the big resistor on the right of the board has one leg that gets loose and causes issues.
Jon
H&W Machine Repair
HWElecRepair
Hot Rolled
- Joined
- Dec 9, 2013
- Location
- Fort Wayne, IN
Just my two cents on this...
Alot of the imports are fire and forget parts... they arent designed or priced to be fixed. Once there is an issue with them, ya fork over another couple hundred bucks to get a replacement.
Here at the shop we sell and service Servo brand powerfeeds as well as their import knockoff Dynamo. We also service Align powerfeeds. Those seem to be cheaper in cost, yet I dont know anything about how they perform on a mill since all I do is fix them.
Cant give any advice on how they operate, but I figured I would put out what I know about which is fixing them.
Jon
H&W Machine Repair
Alot of the imports are fire and forget parts... they arent designed or priced to be fixed. Once there is an issue with them, ya fork over another couple hundred bucks to get a replacement.
Here at the shop we sell and service Servo brand powerfeeds as well as their import knockoff Dynamo. We also service Align powerfeeds. Those seem to be cheaper in cost, yet I dont know anything about how they perform on a mill since all I do is fix them.
Cant give any advice on how they operate, but I figured I would put out what I know about which is fixing them.
Jon
H&W Machine Repair
awake
Titanium
- Joined
- Jan 24, 2006
- Location
- Angier, North Carolina
Is the "big resistor" a low-ohm, high wattage resistor (like 5 ohms, 10 watts)? If so, then following a typical PWM design it likely is used to sense the amount of current going to the motor, to prevent an over-current situation. However, if that is its function, and the resistor is loose, I would expect the motor not to run, rather than to run at full speed - the current to the motor travels through that resistor.
ignator
Cast Iron
- Joined
- Oct 8, 2012
- Location
- Marion, Iowa
Jon; Thank you for the heads up. I'll open it up to see if I can find a cold solder joint to any large component. About the only other down side, is the feed rate range on the pot is very small for where I normally machine. This is also true of the low cost imports.
The one thing nice about the imports is they came with a schematic diagram. I've never opened the Servo, so I don't know if it's using a SCR or TRIAC for half or full wave control (depends also if there is a full wave rectifier in the circuit, import manual show 3 schematic diagrams for the 2 different torque range, as well the CE version where the limit switches have a safe DC level). The imports have the switching device such that back EMF of the motor is not used to improve speed regulation, or I believe that is the case.
HWElecRepair
Hot Rolled
- Joined
- Dec 9, 2013
- Location
- Fort Wayne, IN
@awake man its too early and I dont haven enough coffee in me to try and figure that out... lol naw I just know that I have gotten some really weird issues on Servo 80/140's and when I open it up, it has some bad solders. Mostly its on the resistor and only sometimes on the MOV's... but I dont document that well the gripe and fix on each one. I will keep an eye on this and see if I can duplicate it for you to get back.
HWElecRepair
Hot Rolled
- Joined
- Dec 9, 2013
- Location
- Fort Wayne, IN
@Ignator the Servo 80/140 is a half sine wave and the 100/150 is a full sine wave. And since we are on the subject, the 200 is a half sine wave.
You guys are asking tougher questions than I normally get into. Typically my response when people ask the difference between the 140 and 150 is that the 140 is more power, less control and the 150 is finer feed control, not as much power.
Jon
H&W Machine Repair
capocoreyollo
Aluminum
- Joined
- Jul 22, 2015
Went with an import "servo" style, lasted a couple months, bad pot. Spent an hour or so fixing the old, stock Bridgeport power feed and put it back on it. Just needed to re-adjust the cams. The stop/ linkage bar is a little annoying, covering the t-slot and such on the front of the table, but I'm glad i went back to the old style.
awake
Titanium
- Joined
- Jan 24, 2006
- Location
- Angier, North Carolina
No worries on my part - I'm just being curious!
Sent from my SM-T230NU using Tapatalk
gjrepesh
Cast Iron
- Joined
- Aug 30, 2002
- Location
- Royse City, TX
I've used power feeds from Enco and Harbor Freight. They all worked. I bought them on sale. They were purchase more than five years ago so I can't comment on the reliability of current models.
