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  • Tundra Twin Track
    replied
    Originally posted by Bob La Londe View Post

    I don't understand the question. I bought a brand new South Bend mill. Not a Bridgeport. If you are just picking on me for not choosing a Bridgeport I did look at them. I also looked at a number of other options. The South Bend had everything I wanted. None of the other "packages" did. Everything installed. All I had to do was hook up air and power. I didn't choose it on price either. It was one of the more expensive of the various knee mills I considered. If I just wanted a Bridgeport for the name there were cheaper ones available brand new. They just didn't come packaged with everything i wanted. If I was going to buy based on price I would have probably gotten something Taiwan assembled from Matt over at Precision Mathews. I'm pretty satisfied with my Precision Mathews lathe which I did buy based on price.

    As to how the spindle brake works I have no idea. I did take the power draw bar off once because it didn't seem to be working right, but it turned out to be me not using it right. Other than that I have not been inside the machine. There is a lever on the side of the head. I push it back and it kills power to the spindle motor. Push it back further and it stops the spindle very effectively.

    FYI: It came stock with a 7.5HP VFD to drive the 5HP spindle motor.

    As to the new tech old tech thing.... It wasn't that long ago when it was hard to find 1-3 VFDs rated for full 3ph power at 1-3ph input. Even now when I look them up they tend to be more expensive than an upsized VFD. The problem is most 3-3 units over about 3.7Kw (5HP) are not advertised for 1-3 phase converter operation. You have to dig into the manuals to see if they are capable or not. As an aside, I've got a bunch of machines running VFDs and when I first started doing this PolySpede/Spedestar was the only 1-3 I found rated for 1-3 at full rated power. I was going to put one on the Hurco mill, but I just haven't gotten around to it. I just keep running the 3.7Kw derated Mitsubishi that was in i when I got it. I will upgrade it at some point. The Mitsubishi is limited at 120hz in the menu, and I want to be able to run upto 200hz. When I upgrade I'd like to also be able to get full power. Those machines were run at 200hz with a pricey upgrade from Hurco. From what I have heard talking to guys who had them upgraded back in the 80s and 90s all Hurco appeared to do was upgrade the electronics. Not the spindle.
    Sorry Bob,I read South Bend and my Brain typed Bridgeport,was curious if your Brake had limit switch like you mentioned.I think there’s a variety of styles Band,Shoe&Drum,Disc and maybe some that contacts pulley.

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  • sarge41
    replied
    I'm like mochinist in that I like a mechanical foot brake. I first got used to one on a French made tracer lathe and used it gently. I now have a 15" engine lathe that has an electronic brake that engages when the hand lever is moved to the "off" position. I have used it for about 25 years and no problems, but would rather have a foot pedal that can be used softly.
    Sarge41

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  • mochinist
    replied
    Yes…
    I’ve used lot’s of different manual lathes with foot brakes, all of them were just like my vehicles, you can gently apply the brake and slow it down relatively fast, compared to just letting it spin down slowly on its own or you can step on it as hard and fast as you can, and stop it almost instantly. No need for the latter unless its an emergency though. Maybe your lathe brake is different?

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  • Bob La Londe
    replied
    Originally posted by Tundra Twin Track View Post

    Bob what style of Brake does your Bridgeport have..
    I don't understand the question. I bought a brand new South Bend mill. Not a Bridgeport. If you are just picking on me for not choosing a Bridgeport I did look at them. I also looked at a number of other options. The South Bend had everything I wanted. None of the other "packages" did. Everything installed. All I had to do was hook up air and power. I didn't choose it on price either. It was one of the more expensive of the various knee mills I considered. If I just wanted a Bridgeport for the name there were cheaper ones available brand new. They just didn't come packaged with everything i wanted. If I was going to buy based on price I would have probably gotten something Taiwan assembled from Matt over at Precision Mathews. I'm pretty satisfied with my Precision Mathews lathe which I did buy based on price.

    As to how the spindle brake works I have no idea. I did take the power draw bar off once because it didn't seem to be working right, but it turned out to be me not using it right. Other than that I have not been inside the machine. There is a lever on the side of the head. I push it back and it kills power to the spindle motor. Push it back further and it stops the spindle very effectively.

    FYI: It came stock with a 7.5HP VFD to drive the 5HP spindle motor.

    As to the new tech old tech thing.... It wasn't that long ago when it was hard to find 1-3 VFDs rated for full 3ph power at 1-3ph input. Even now when I look them up they tend to be more expensive than an upsized VFD. The problem is most 3-3 units over about 3.7Kw (5HP) are not advertised for 1-3 phase converter operation. You have to dig into the manuals to see if they are capable or not. As an aside, I've got a bunch of machines running VFDs and when I first started doing this PolySpede/Spedestar was the only 1-3 I found rated for 1-3 at full rated power. I was going to put one on the Hurco mill, but I just haven't gotten around to it. I just keep running the 3.7Kw derated Mitsubishi that was in i when I got it. I will upgrade it at some point. The Mitsubishi is limited at 120hz in the menu, and I want to be able to run upto 200hz. When I upgrade I'd like to also be able to get full power. Those machines were run at 200hz with a pricey upgrade from Hurco. From what I have heard talking to guys who had them upgraded back in the 80s and 90s all Hurco appeared to do was upgrade the electronics. Not the spindle.

    Leave a comment:


  • Tobias-B
    replied
    yeah, I have been meaning to fix the brake on the mill for ages.

    And I hadn't given the lathe much thought- but fitting a disc
    and a caliper in the cabinet below wouldn't be hard at all.

    Of course, the threaded spindle nose might have something to say about that...

    t

    Leave a comment:


  • Noitoen
    replied
    When I installed a new motor on my lathe for the VFD, I also installed a bicycle brake disk. It helps with threading a lot. I I press the pedal lightly it will coast to stop by just stopping the VFD and pressing harder will actuate the caliper and I can stop almost instantaneously if I want but then i'ts just a small lathe
    You may only view thumbnails in this gallery. This gallery has 5 photos.

    Leave a comment:


  • Tundra Twin Track
    replied
    Originally posted by Bob La Londe View Post

    I haven't had the new South Bend Knee Mill a full year yet, but I've gotten spoiled with the spindle brake. I think that's something I would fix if it was worn out. I use a spanner on the keyless chuck all the time when I need to do heavy drilling with one hand on the brake lever, and the spindle brake makes for easy quick tightening by hand for light drilling and spotting.



    Bob what style of Brake does your Bridgeport have,I’ve also gotten spoiled by having a Click image for larger version

Name:	CE47F99A-D34A-442B-B362-535606FBF021.png
Views:	179
Size:	2.00 MB
ID:	1981970 Brake on my Varnamo great for tooling changes in Park Mode.

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  • Tundra Twin Track
    replied
    [QUOTE=BCRider;n1981953]
    Originally posted by Tundra Twin Track View Post

    Gotcha. Sort of a middle ground before stepping up to the big stuff where the motor runs for the whole session? I see that on lots of the bigger lathes in various machining videos.

    I do a lot of stopping and starting on my 12x36 to get measurements or for small parts. From medium fast to stopped I timed mine just now out of curiousity and it seems to be roughly 1.8 seconds with the 6" chuck. From medium slow it's just under 1 second. And when I'm in a rush to get on with things that 1.8 seconds seems nigh on FOREVER ! ! ! !

    These times go up by probably double when the 8" four jaw "lump" is on the machine. I didn't swap chucks to time it but it always made me notice how much longer the spin down required. And come to think of it this alone makes me happy that I've never felt the need to step up to an 8 inch three jaw. It's so rare when I need the extra size that I just swap to the 8" four jaw. And being a 4 jaw it has a generous center bore to boot.

    Bob, I'm glad you got a chuckle out of my "making the chips jump" comment ....
    The Brake Drum on mine is mounted on Motor Shaft and will stop the 12” Chuck in a split second if needed,I rarely ever STAND ON IT that hard.

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  • BCRider
    replied
    [QUOTE=Tundra Twin Track;n1981950]
    Originally posted by BCRider View Post
    I envy you guys with the machines that can just disengage a clutch and brake the spindle for doing work that requires frequent stops.

    BC a lot of Lathes with Foot Brake don’t have a clutch, The foot brake kills power to the Motor before any braking takes place.
    Gotcha. Sort of a middle ground before stepping up to the big stuff where the motor runs for the whole session? I see that on lots of the bigger lathes in various machining videos.

    I do a lot of stopping and starting on my 12x36 to get measurements or for small parts. From medium fast to stopped I timed mine just now out of curiousity and it seems to be roughly 1.8 seconds with the 6" chuck. From medium slow it's just under 1 second. And when I'm in a rush to get on with things that 1.8 seconds seems nigh on FOREVER ! ! ! !

    These times go up by probably double when the 8" four jaw "lump" is on the machine. I didn't swap chucks to time it but it always made me notice how much longer the spin down required. And come to think of it this alone makes me happy that I've never felt the need to step up to an 8 inch three jaw. It's so rare when I need the extra size that I just swap to the 8" four jaw. And being a 4 jaw it has a generous center bore to boot.

    Bob, I'm glad you got a chuckle out of my "making the chips jump" comment ....

    Leave a comment:


  • Tundra Twin Track
    replied
    [QUOTE=BCRider;n1981896]I envy you guys with the machines that can just disengage a clutch and brake the spindle for doing work that requires frequent stops.

    BC a lot of Lathes with Foot Brake don’t have a clutch,the foot brake kills power to the Motor before any braking takes place.

    Leave a comment:


  • Captain K
    replied
    There is no need to oversize the vfd. If it’s single phase input it will put out rated hp. The derating thing is out of date. This is with quality, genuine drives. All bets are off on others.

    Leave a comment:


  • Bob La Londe
    replied
    Originally posted by Tobias-B View Post
    ...but as the brake on the Bridgeport's worn out,
    I haven't had the new South Bend Knee Mill a full year yet, but I've gotten spoiled with the spindle brake. I think that's something I would fix if it was worn out. I use a spanner on the keyless chuck all the time when I need to do heavy drilling with one hand on the brake lever, and the spindle brake makes for easy quick tightening by hand for light drilling and spotting.




    Leave a comment:


  • Bob La Londe
    replied
    Originally posted by BCRider View Post
    You just want to avoid a sudden SLAM! that makes the swarf jump up in the chip tray.
    Um, yeah. LOL. Lets not do that.

    I'm not 100% convinced on going to 3 phase, but I would go with the typical 30-40% over size just like I would on any other 1 to 3 phase VFD application.
    Last edited by Bob La Londe; 01-20-2022, 08:23 PM.

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  • Tobias-B
    replied
    Seconded for the VFD braking-
    if I had a foot brake, I'd use it, but as the brake on the Bridgeport's worn out,
    and the lathe never had one,
    setting the braking appropriately sure saves time on both machines.

    So yes, if I HAD one, I'd use it!

    t

    Leave a comment:


  • Captain K
    replied
    I can’t help with the foot brake question. However I did install a vfd with properly sized braking resistor on my 3hp Colchester Student and it works awesome. I think I set it for a second or less to stop. It works flawlessly up to max 1500rpm speed of the lathe with a 6 or 8 inch 3 jaw chuck. I don’t run the 4 jaw that fast. The vfd is a Fuji Frenic

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