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Moya
Thanks for the info. The interesting point is that many replies to this question (Kvom, Machine Tom, etc) are from people who are doing just the opposite. Using the pot, soft motor start, dynamic braking. I assume their mills haven't broken.
I understand that RPC, a 90 year old technology is well proven. I did call Hardinge/Bridgeport and while they said, as did you, to vary the speed with the mill for maximum torque, many of their customers are using VFDs and have had no issues. The tech said that the "old" motors (as opposed to their newer, VFD friendly ones) can be run over speed for short periods. When I asked him to define a short period he said he wouldn't do it for more than 15-30 minutes at a time.
 
Sshire said:
Moya
Thanks for the info. The interesting point is that many replies to this question (Kvom, Machine Tom, etc) are from people who are doing just the opposite.
Click to expand...

The way I look at it, there are many things you can do to a machine that probably won't hurt it but you never know what the cumulative effect is. Being that we don't run production shops, you may very well never see an ill-fated cumulative effect from a certain procedure.

I do not claim to be an expert on the topic, and if I come across that way, without making any disclaimers, forgive me. I have, however, done quite a bit of extensive research as I have a vari-speed mill myself, have been playing with electricity and electronics since the 4th grade, and have spoken on the phone at length with a Republic Lagun engineer about this very topic.

Most mills of this type have plastic gears in them that are designed to fail if something goes wrong. You don't really want to replace these due to cost and complexitiy.
 
Nice find, Stan. I'm glad to see that Cook Machinery is still around. I used to go there all the time, but it's been 8 or 10 years since I've been there. Nice people!
cheepo45
 
Moya
I really appreciate your take on this. I'm always open to information.
I also think you hit the most important point. I (can't speak for others) probably use my mill less in a month than a production, or even a job shop, does in a shift. It might be interesting to have an hour meter on the mill.
Your point is correct. I would probably would never (fingers crossed) have a problem given the low usage.
That said, I did order the Bridgeport rebuild manual and also have Bridgeport's maintenance manual and with the step by step directions, should be able to fix anything. I think of a Bridgeport like a 1960's automobile. Easy to fix. No electronics. No computer diagnosis required.
 
The only issue with overspeeding the motor is heat, and 20 minutes is a very long time to run on these mills at a single time.

There is absolutely nothing wrong with running the VFD at 60Hz and using the head to control RPM most of the time. But If you have a small drill and want higher spindle speed you can raise the VFD frequency without worry.
 
Kvom

I can't image running at high speed for more than a minute or 2. Stopping to replace the broken 1/16" end mills should allow the motor to cool. :)
 
The only time I've run my mill's motor for more than a couple of minutes has been sizing some large plates with a fly cutter.
 
It's home!!!
Full report and videos tomorrow. A few teasers to hold you over.

[ame]http://www.youtube.com/watch?v=-VUBS8w7Bjw[/ame]

[ame]http://www.youtube.com/watch?v=bJkZx7CFgCg[/ame]

 
Yesterday morning I drove to Cook Machine to follow the Bridgeport to its new home.
Jim and Tom Cook know more about machine tools than anyone I've met and I spent too much time with Tom listening to his dissertations on "Textron Bridgeports", Why Oliver Tool and Cutter Grinders are exceptional pieces of engineering and a quick look at a Monarch 10EE that had just recently come in.. Before we took off, he gave me an original Bridgeport manual and a color brochure (circa 1962) of the Series 1.

Jim and Tom loaded the mill onto the truck and strapped it down. I followed most of they way and then led Jim through the back roads to my house.

The traverse of the yard was without incident. Nothing torn up, no ruts no divots and not a broken branch.

After having seen many Youtube videos of "self-moved" Bridgeports with the mill owner, 7 friends, a case of beer, a borrowed trailer and an engine hoist, I was more than a little apprehensive about one guy moving 2000+ pounds into the shop and putting it in the opening I had cut in the shop's wooden floor so the mill would be directly on concrete. This was, obviously, not his first rodeo.

Off it came via the crane onto a pallet jack. He rolled it over to the door, and placed and moved wooden blocking like a puzzle to make the 4" height difference. Onto 2 pieces of steel pipe as rollers. I was the designated pipe mover and placer. At Jim's direction, I'd angle a pipe and with one push, the mill began the 90 degree turn. Move the pipe again. I was directed to place the pipe at some angle that he knew instinctively, another push and the mill almost turned by itself.

I had made the cutout in the wooden floor (top of floor to slab is only 1.5") 6" larger than the mill base. I measured it last night and he put it in that opening only ¼" off center, side to side and ½" off, front to back.

Total time from the time the truck started across the lawn until done: 1 hour 8 minutes!!
Nothing like a professional.

So here is the video. Enjoy.

[ame]http://www.youtube.com/watch?v=tINc3jxAPlM[/ame]
 
I'm curious how the machine made it off the pallet jack and on to the floor. I'm also curious what it costs to hire someone for a job like that.
 
Thanks for the video, I have never seen a Bridgeport table with only 2 "T" slots in it before. What a lovely part of the country you live in.

Paul.
 
Moya
The mill was pushed up to 4" elevation on the jack so the rear of the base was against the edge.
Jacked up and 2x4s and 4x4s went under between the forks. Jack lowered. That got the bottom of the base casting 2" above the floor. Jack removed. Some sort of 6 foot long handle with steel wheels and a hooked end (I forget the name) under the front of the casting. Jim lifted the front while I slid a pipe in. The same routine with the same device lifting the rear of the casting. I put another pipe under. The a push and it rolled right in. Move mill about 8", and keep moving front pipe to the rear.
The rigging cost was $350.00 which I think is very low compared to the riggers I checked. Of course, I did buy the machine from them so it is a bit of "value added"

Swifty
I think both the 32" and 36" tables are 2-slotters. Someone please correct me if that's incorrect.
I am quite taken with the Northeastern part of this country. Seasonal changes. My brother is in Arizona and it's hot and sunny nearly every day. Boring. It's wonderful looking out of the shop doors and seeing deer and the occasional fox wandering along the stream.
 
Stan...this video was amazing. I really enjoyed the time and effort you put into that video. I am currently on the hunt for a Bridgeport and having just visited the American Precision Museum in Vermont to see the 1st Bridgeport I cannot wait until I find one (or have the $$$).

After watching your video I am less concerned on how the machine will make it through my backyard and in its new home.

Thank you for that video!!!
 
Chris,
Thanks for the,more than kind, comments.
The museum is on my summer road trip list.
The invoice for BP #1 was $995.00.
 
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