Boss5 Pulley & Belts Size - Verify

[PeteW]

I would like to get a verification on the original Pulley Size and Belts used on the Bridgeport Boss5 Series I Mill.

I am going to start a retrofit on my Boss5 machine since the Controller finally took a dump. My plan is to go with servos and the Pico-System with EMC.

I have yet to start ripping off the original electronics and boxes. I am thinking on trying to keep the electronics for the spindle motor only .... that is, if I can figure what I need to keep and what needs to go.

My question to those who have been down this road is, for now, the verifcation of the original Pulley Size and
Belts used on this design. That way I can find a supplier and price the new pulleys and belts I will need to purchase before I pick out the servos I will go with. I do not want to get a servo with it's shafts too large or too small as to place me in the higher costing pulleys and belts.

I think the original design has:

1.) 5/8" shaft on the drive end of the existing stepper motors.

2.) These are 1.0" wide pulleys and belts used on the existing design. Both motor pulleys and leadscrew pulleys.

3.) .500" Pitch "H" type belts on all three axes.

4.) Not sure what size the shaft on the leadscrews that the pulleys mount too... or the key method used?

Thanks for any input.

--Pete W

[unterhaus]

do you have the ballscrew head? If so, you should do whatever you can to keep the existing pulley. I still haven't tracked down a replacement for the 13 tooth pulley that was originally installed on mine. That belt is 3/4" on my mill. All your other specs match what I've seen on these mills.

You can get servos with 5/8 shafts and just use the existing pulleys. Otherwise your best bet is to stick with H 1/2 inch pitch pulleys and leave the leadscrew pulleys alone.

I would think hard before moving away from the existing steppers if they are good. Geckos work for a lot of people.

[PeteW]

Thanks unterhaus,
I do not know if I have the ballscrew head. I will need to take off the existing covers and see what it looks like.
When you say 13 tooth pulley, are you referring to the pulley on the ballscrews or the motor shaft? Do you think all three axes have the 13 tooth pulley on them (Ballscrew end)?
The problem with using the existing pulleys would be to get the 2:1 ratio deduction. If the 13 tooth is the smallest pulley (odd size, all I can find is 14 tooth and larger) on the ballscrew, well it would be hard to go with a smaller pulley on the motor shaft for 2:1 ratio reduction.

I am all for trying to use the existing pulleys to save $$$.
I have yet to check out how easy the ballscrew pulleys will come off and be replaced.

Why do you think using the existing steppers would be a better route to go. From everthing I have read on the forums, the Gecko does not work very well with these existing steppers because of the ampager they draw and the stepper motor in general do not have much power under higher speed machining. Am I missing something here? I certainly believe it would be the most cost effective way out, but that would be at a cost of power at higher speeds and smoothness wouldn't it? I also understand that the Gecko fry pretty easy when used with these existing stepper motors. After frying a couple Geckos I would regret not going with another solution.

Pete W.

[unterhaus]

do you have a mill that looks like this one:
http://cgi.ebay.com/BRIDGEPORT-SERIE...ayphotohosting

If so, you have the ballscrew spindle. The 13 tooth pulley is used on the motor, the spindle uses a 26 tooth pulley. I have also heard that the motor can use a 26 tooth pulley. The X and Y motor pulleys are 14 teeth, and the ballscrew pulleys are 28 teeth. Like I said, I don't see any reason to change those, and if you have a ballscrew head, you can't afford to change that.

I have also seen a lot of people that had problems with the original steppers and Geckos. Other people haven't had those problems. I would get the newer stepper drive with the protection circuits. Marriss of Gecko will repair or replace a drive at least once for free, so that is somewhat less of a worry.

My point is that you should do as little work as you can and get running again as soon as you can. I can certainly see your point that you wouldn't want to have to do everything over again twice, and your motors are worth something on Ebay. I wasn't warning you against the change, I just think you should make sure the extra expense and effort are worth it to you. I have gone with servos on my machine, but all the control hardware and motors were stripped before I got it.

[PeteW]

Yes, very similar mill. Here are the pictures of my mill:

LINK

Last night I took the covers off the “X” & “Y” axes to count the teeth on the pulleys and measure the distance between the center-line of the ball screw to the center-line of the drive motors.

For the “X” axes I got both pulley counts at 16 tooth, running at 1:1 ratio with a 6.500” distance between centers.

For the “Y” axes I got both pulley counts at 18 tooth, running at a 1:1 ratio with a 7.500” distance between centers.

You can see the pictures I took below.

Still not sure if I have a “ballscrew head” or not, since I am not sure what that looks like.

You mentioned that you “have gone with servos on my machine, but all the control hardware and motors were stripped before I got it.” Well, this is what I want to do.

Did you use the existing electronics/power supply for the Spindle motor?
What size servos did you used? (20 in-lbs or larger with a 1:1 ratio ?)

What drivers did you end up going with?

What is your fastest move in IPM?

Maybe I can PM you on a few other question?

I see you are only about 54 miles from me according to your location signature.

Here is the "X" axes Pulley, which I counted as have 16 teeth on both pulleys:

Large Picture: Here


Larger Picture: Here


Larger Picture: Here

Here are the "Y" axes Pulleys:

Larger Picture: Here

[HillBilly]

I have a breakout board that is perfect for interfacing Mach3 to the existing drives of the BOSS stepper machines. I have a prototype of this circuit that has been in operation since 1991. It only replaces the control, this will not increase rapids or resolution but will increase memory, allow 3D machining, program plot, G code and all axis displayed! If you upgraded to S&D servos later the board would still be needed.

Darek

[PeteW]

Originally Posted by HillBilly I have a breakout board that is perfect for interfacing Mach3 to the existing drives of the BOSS stepper machines. ..... If you upgraded to S&D servos later the board would still be needed. Darek

Hello HillBilly,

Sounds good... have a few question though....
1.) How much is it?
2.) What features does it have to offer over this Breakout Board?
See Link: Here

The only problem I can't over come with this board is using the parallel port on the PC, which would restrict me to 45K Steps(Counts)/sec max. using Mach3 software.
Using the EMC software and the Pico-System with Servos I can get 125K or even 250K Steps(Counts)/sec as long as I can find an encoder to produce that many CPRs.

Still thinking about what route to go though... and what to spend $$$ on.

Thanks

Pete W.

[HillBilly]

Pete,

One setup like the one in the picture for a bridgeport would be $69.

Here are some post that will tell you more.
http://www.cnczone.com/forums/showthread.php?t=7943

A link to the schematic
http://home.icx.net/~ashburn/sitebui...ures/schem.jpg

The steps(counts)/sec with the original drives will not be a issue. They were 1000 counts per inch (.001 resolution.). Even if you went to servos with 10,000 counts per inch (.0001 resolution) you could achieve 200 inch per minute rapids.

Darek

[sdeering]

Hill Billy I am interested in your bord. I have a boss 5. I am thinking of doing a retro. I have a transformer and caps for the DC PS.
If I remember correctly your bord uses all the origional power supply, reactors, drives, acc card etc. I will be running Mach3. What does the bord hook up to the slots the origional cards are pluged into or the drivers. I have replaced all the transistors in the origional drives and the mill is running as origional. Does your card come with some instructions and help if needed?
Thanks Stephen

[HillBilly]

Stephen,

Sorry for the delay in answering (For some reason I though I did.). Yes I have put together some very detailed instructions on doing the BOSS machines. The feedback I have gotton so far on the instructions has been good.

Darek

[PeteW]

Hello Stephen,

I am now in the process of converting my Boss5 over to the
Universal Board Darek designed. I have yet to get it hooked-up. I have ripped out the Card cage and PC power supply cage as per Darek's instructions. Hopefully I will get to try it out this week. I will keep you posted on my results.

Pete W.

Originally Posted by sdeering ...... Does your card come with some instructions and help if needed? Thanks Stephen

[Eric]

Originally Posted by PeteW Hello Stephen, I am now in the process of converting my Boss5 over to the Universal Board Darek designed. I have yet to get it hooked-up. I have ripped out the Card cage and PC power supply cage as per Darek's instructions. Hopefully I will get to try it out this week. I will keep you posted on my results. Pete W.

Any updates?