New Project - Bridgeport Boss CNC Retrofit
I have a new project. Recently a series 1 Bridgeport BOSS CNC milling machine was posted on Craigslist. The machine was in the process of being retrofitted as the control went down and a previous owner threw it away. It came with a couple tool holders, some Gecko stepper drivers, some software packages and all the manuals. I contacted the seller to ask about its availability. It was available so I made arrangements to go inspect the machine.
In the meantime I learned a little about Bridgeport BOSS CNC milling machines. Basically they are similar to manual Bridgeport milling machines but have ball screws and big stepper motors that drive the screws on the X, Y, and Z axis. They do not run manually. Also they have pretty obsolete controls that were quite capable for their time. The stock controls have a resolution of 0.001 and have 200 step per revolution motors with 1:1 pulleys. But basically they are VERY capable machines when retrofitted and a similar ball screw CNC mill with that rigidity and capability is not available for less than $7000. They are also reported to be fairly easy to retrofit.
So YES, we decided to get it. I drove up to the seller's residence and viewed the machine. under a coat of old grease was a machine with little apparent wear. The grease was dry and sticky though and would need to be removed. The motor data plate showed that it was 3 phase 208. I knew that with a phase converter you can make 3 phase out of 2 phase.
The seller was pretty knowledgeable about machines and had a CNC machining center that he uses to make decorative western belt buckles and "real" spurs. He didn't have time for the retrofit and had a full shop already. In the Craigslist ad he listed that he could deliver the mill.
I paid him for the machine and arranged delivery. He had a trailer and could load the machine and I would get rent a skid steer to unload the machine. I briefly had looked at using a tilt trailer and rollers to move the machine but after talking to a local machinist, Tony at Knick's Machine, decided that lifting it would be easier. Since the seller had moved machines before, I trusted him to be knowledgeable about moving the machine.
The next step for me was to make space in the garage. This is where an able and supportive fiancee really helps. It took us only 12 hours to get the garage all moved and arranged and about 5 cubic yards of garage sale stuff out on the porch. I gave the machine an open area 9'x10' since I would be working on the machine. Also this machine only has one control cabinet on the back and is missing the tape drive box.
The seller brought the machine down to Bozeman on a big flatbed trailer. He tied it down with chains and a nylon lifting strap. He used the knee to tighten up the nylon strap (later I found that the one Y limit switch stop was bent slightly). I rented a skid steer (Bobcat) with pallet forks to lift the mill off the trailer. When the seller and I went to pick it up he noted that the Bobcat probably wasn't rated to lift the mill. We changed the rental to a fork lift with 4 wheel steering which had 5000 lbs rating. The price for a 2 hour fork lift rental, a trailer, and a gallon of fuel was less than $100.
We got the machine off the trailer and into the garage with no mishaps. By lowering the mill almost to the floor we were able to get the fork lift into the garage. Once the mill was down we were able to spin it slightly to get it straight. The machine has no leveling feet so it will spin if two people push hard enough.
In the meantime I learned a little about Bridgeport BOSS CNC milling machines. Basically they are similar to manual Bridgeport milling machines but have ball screws and big stepper motors that drive the screws on the X, Y, and Z axis. They do not run manually. Also they have pretty obsolete controls that were quite capable for their time. The stock controls have a resolution of 0.001 and have 200 step per revolution motors with 1:1 pulleys. But basically they are VERY capable machines when retrofitted and a similar ball screw CNC mill with that rigidity and capability is not available for less than $7000. They are also reported to be fairly easy to retrofit.
So YES, we decided to get it. I drove up to the seller's residence and viewed the machine. under a coat of old grease was a machine with little apparent wear. The grease was dry and sticky though and would need to be removed. The motor data plate showed that it was 3 phase 208. I knew that with a phase converter you can make 3 phase out of 2 phase.
The seller was pretty knowledgeable about machines and had a CNC machining center that he uses to make decorative western belt buckles and "real" spurs. He didn't have time for the retrofit and had a full shop already. In the Craigslist ad he listed that he could deliver the mill.
I paid him for the machine and arranged delivery. He had a trailer and could load the machine and I would get rent a skid steer to unload the machine. I briefly had looked at using a tilt trailer and rollers to move the machine but after talking to a local machinist, Tony at Knick's Machine, decided that lifting it would be easier. Since the seller had moved machines before, I trusted him to be knowledgeable about moving the machine.
The next step for me was to make space in the garage. This is where an able and supportive fiancee really helps. It took us only 12 hours to get the garage all moved and arranged and about 5 cubic yards of garage sale stuff out on the porch. I gave the machine an open area 9'x10' since I would be working on the machine. Also this machine only has one control cabinet on the back and is missing the tape drive box.
The seller brought the machine down to Bozeman on a big flatbed trailer. He tied it down with chains and a nylon lifting strap. He used the knee to tighten up the nylon strap (later I found that the one Y limit switch stop was bent slightly). I rented a skid steer (Bobcat) with pallet forks to lift the mill off the trailer. When the seller and I went to pick it up he noted that the Bobcat probably wasn't rated to lift the mill. We changed the rental to a fork lift with 4 wheel steering which had 5000 lbs rating. The price for a 2 hour fork lift rental, a trailer, and a gallon of fuel was less than $100.
We got the machine off the trailer and into the garage with no mishaps. By lowering the mill almost to the floor we were able to get the fork lift into the garage. Once the mill was down we were able to spin it slightly to get it straight. The machine has no leveling feet so it will spin if two people push hard enough.
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