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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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Bridgeport Quality
I bought my Bridgeport mill new in 1981. Today I just finished power
tapping a bunch of 5/16-18 through holes in .5 thick 7075 aluminum. With the mill in low range at 250 RPM. I just put the tap in the drill chuck, turn the spindle on forward till the tap is through and then plug reverse the motor and back the tap out. I can't even begin to count how many holes I have tapped this way on this machine. I have never overheated the motor or switch gear and they are still original. The motor has the "tropical insulation" in it so I guess that means it can stand hot humid running. I don't know if a new Bridgeport today would hold up as well, I hope they would. I do know of more than one import mill that has cooked a motor and/or the switch gear. Eric |
#2
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Bridgeport Quality
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#3
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Bridgeport Quality
On Tuesday, April 14, 2015 at 4:11:50 PM UTC-7, wrote:
I bought my Bridgeport mill new in 1981. Today I just finished power tapping a bunch of 5/16-18 through holes in .5 thick 7075 aluminum. With the mill in low range at 250 RPM. I just put the tap in the drill chuck, turn the spindle on forward till the tap is through and then plug reverse the motor and back the tap out. I can't even begin to count how many holes I have tapped this way on this machine. I have never overheated the motor or switch gear and they are still original. The motor has the "tropical insulation" in it so I guess that means it can stand hot humid running. I don't know if a new Bridgeport today would hold up as well, I hope they would. I do know of more than one import mill that has cooked a motor and/or the switch gear. Eric I'm always amazed when people rave over a Bridgeport. It means they have no idea what modern CNC machine tools are capable of and they are completely out of touch with the reality of how machining is done today. |
#5
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Bridgeport Quality
On Tuesday, April 14, 2015 at 9:44:40 PM UTC-5, jon_banquer wrote:
On Tuesday, April 14, 2015 at 4:11:50 PM UTC-7, wrote: I bought my Bridgeport mill new in 1981. Today I just finished power tapping a bunch of 5/16-18 through holes in .5 thick 7075 aluminum. With the mill in low range at 250 RPM. I just put the tap in the drill chuck, turn the spindle on forward till the tap is through and then plug reverse the motor and back the tap out. I can't even begin to count how many holes I have tapped this way on this machine. I have never overheated the motor or switch gear and they are still original. The motor has the "tropical insulation" in it so I guess that means it can stand hot humid running. I don't know if a new Bridgeport today would hold up as well, I hope they would. I do know of more than one import mill that has cooked a motor and/or the switch gear. Eric I'm always amazed when people rave over a Bridgeport. It means they have no idea what modern CNC machine tools are capable of and they are completely out of touch with the reality of how machining is done today. Some of us, well actually mechanics, are hands on in over under types. We have machinists just make us parts. |
#6
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Bridgeport Quality
"jon_banquer" wrote in message
... On Tuesday, April 14, 2015 at 4:11:50 PM UTC-7, wrote: I bought my Bridgeport mill new in 1981. Today I just finished power tapping a bunch of 5/16-18 through holes in .5 thick 7075 aluminum. With the mill in low range at 250 RPM. I just put the tap in the drill chuck, turn the spindle on forward till the tap is through and then plug reverse the motor and back the tap out. I can't even begin to count how many holes I have tapped this way on this machine. I have never overheated the motor or switch gear and they are still original. The motor has the "tropical insulation" in it so I guess that means it can stand hot humid running. I don't know if a new Bridgeport today would hold up as well, I hope they would. I do know of more than one import mill that has cooked a motor and/or the switch gear. Eric I'm always amazed when people rave over a Bridgeport. It means they have no idea what modern CNC machine tools are capable of and they are completely out of touch with the reality of how machining is done today. CNC is little help without a CAD file, which you don't have when making repair parts. Segway's experimental parts were mostly made manually, cut-to-fit, on a CNC Bridgeport and lathe. I rarely saw them running CNC files, usually an engineer was working from a sketch and inventing the part on the fly. The files that castings had been made from didn't help without the production machining fixtures to position them. I had to reconstruct their hole patterns relative to locatable reference features, then locate and center-punch new holes with a height gauge and dividers while they weren't stressed by clamping. Thin-walled plastic injection moldings were particularly difficult to clamp securely enough without distorting them. Expensive CAD seats were in heavy demand. The only one I could borrow was for the powerful but quirky circuit board design program which didn't talk to SolidWorks or the milling machine. It was quicker to just manually mill a one-time part from the drawing while the machine was free than to manually translate and enter the G code. There was a considerable speed advantage in being able to make non-production stuff in-house rather than cleaning up the drawing enough to send it out. -jsw |
#7
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Bridgeport Quality
On Wednesday, April 15, 2015 at 4:57:12 AM UTC-7, Jim Wilkins wrote:
CNC is little help without a CAD file, which you don't have when making repair parts. Wrong. Very wrong. Want proof of just how wrong you are, just ask. |
#8
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Bridgeport Quality
On Tue, 14 Apr 2015 21:14:10 -0500, Ignoramus7898
wrote: On 2015-04-14, wrote: I bought my Bridgeport mill new in 1981. Today I just finished power tapping a bunch of 5/16-18 through holes in .5 thick 7075 aluminum. With the mill in low range at 250 RPM. I just put the tap in the drill chuck, turn the spindle on forward till the tap is through and then plug reverse the motor and back the tap out. I can't even begin to count how many holes I have tapped this way on this machine. I have never overheated the motor or switch gear and they are still original. The motor has the "tropical insulation" in it so I guess that means it can stand hot humid running. I don't know if a new Bridgeport today would hold up as well, I hope they would. I do know of more than one import mill that has cooked a motor and/or the switch gear. I came across a pallet of five burned Excello motors. Eric I'm not surprised. I have ran Excello mills and hate them. But I know folks who love them and think they are the best. Eric |
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