[kewl_cat]

I have 3 Bridgeports all retrofitted wth new electronics and running on Mach 3. I an now looking at getting rid of the noisy/clumsy vari-drives and going with a VFD. Probably going to go with a Hitachi with Modbus capability to control from Mach 3. I would like to get ideas on how some of you have done away with the vari-drives? What type of pulleys and belts? I have read mention of v-belts as well as cam belts. And where did you purchase your parts and what did you fabricate? Some pics and or ideas would be greatly appreciated.

[sharp-shooter]

I'm looking for the same info. I have a R2E3 that has been retro fitted with an Anilam 3000 controller. The VFD conversion will be no problem. I like the idea of more RPM, but like you the clunky vari-drive has to go. I have replaced the plastic bushings several times in the last 2 years an am tired of the maintenance. I would like to change over to a fixed pulley system, using a timing belt or a multiple v type belt. If I can't find the pulleys, I will fab them up. The big question is: what is the optimum ratio for spindle speed?
I do a lot of high RPM cutting ( mostly wood) with router bits, so the higher the RPM, the better. I know the spindle will take more RPM(more than 4200) but the vari-drive pulleys seem to be the biggest problem. Going to a fixed pulley should make things a lot quieter and result in less vibration. I'm just wondering...should the gearing be set the same as it would be when the spindle is normally at it's higest speed?

[mactec54]

sharp-shooter

You don't want to use timing pulleys, unless you want to do rigid tapping, Poly-v Belts is the only right thing to use, in the photos you will see how to do it
it's best to make the pulleys & parts you need

[sharp-shooter]

That's good info Mac. What is that between the pulleys, a belt tensioner? It looks like you went 1:1 ratio.. wha'ts the max rpm you can get?

[mactec54]

sharp-shooter

That's a double piston pneumatic Brake in front of it you can see the Disc

The max for this one was 6,000 RPM

[sharp-shooter]

Please tell me more about your conversion. I noticed an additional cooling fan above the motor, and what kind of drawbar set-up is that?
After closer inspection of the head, I noticed that it didn't look like any head that I've seen before. Apparently it doesn't have a back gear for low range?

[kewl_cat]

Very nice.

[mactec54]

Please tell me more about your conversion. I noticed an additional cooling fan above the motor, and what kind of drawbar set-up is that?
After closer inspection of the head, I noticed that it didn't look like any head that I've seen before. Apparently it doesn't have a back gear for low range?

When using a VFD the normal motor fan does not work as it should at low speeds, so I removed the motor fan,The motor you see is the standard Bridgeport 3Hp with the steel outer case removed, I used a 4" fan on top, the fan is turned on by the Vfd most have a rely output that you can use for the fan

The back gear on this one was removed, a total of 5" was removed out of the top of the head, The spindle is a QC30, what you see on top of the spindle is a 1024 Encoder

[sharp-shooter]

Ah ha....I knew that had to be a bob job....outstanding work, looks factory. It took me a while to figure out that you had to be using QC tooling. My spindle was originally an Erickson QC 30, but I drilled out the spindle and installed a power drawbar. I'll have to mount the encoder on the motor. Can you give me some specifics on the encoder? Right now I'm sourcing all the components for this conversion, so a point in the right direction will be helpful.

[mactec54]

sharp-shooter

The Encoder is for rigid tapping, you have to have a control that can use the encoder feed back, for it to be of any use, the Encoders I used were made by Renco the one in the photo is P/N 79992-020 I used (2) different Encoders from Renco 1024 count per rev & 2048, Encoders can be timing belt driven & mounted off to the side of a spindle, works just as well, lots of machines do it this way because of tool-changers Etc

[tcmachine402]

Is the air brake something you made or did you purchase it? Do you need a brake, wont the VFD brake the motor?

[keebler303]

Is the air brake something you made or did you purchase it? Do you need a brake, wont the VFD brake the motor?

A QC30 spindle requires tightening and loosening a nut on the end of the spindle to change tools. The brake is to hold the spindle stationary while you do so. It isn't for slowing down the spindle, the VFD can stop it quite quickly with regenerative braking.

[mactec54]

Is the air brake something you made or did you purchase it? Do you need a brake, wont the VFD brake the motor?

Everything except for the air fittings mounting hardware, was designed & machined in my shop, all of the machine & Head Mods/parts were custom designed for these machines

You need a Brake only for tool changing on these machines, the VFD braking can only be used for stopping the spindle, the machine brake can not be used while the VFD is running the spindle, or for slowing it down

[Al_The_Man]

It isn't for slowing down the spindle, the VFD can stop it quite quickly with regenerative braking.

On machines that I have converted, B.P.s and XLO's where Quik-Switch tooling is used I used an output on the VFD set to operate at zero speed to take the brake off, this way I ensure the brake is off as soon as the spindle starts, I have a manual overide switch if the brake is on and I need to turn the spindle for some reason.
This signal can also be used by auto tool changers to inform the spindle has stopped.
I also used another output to register up-to-speed, for a FIN signal to inform the controller that a M3/M4 is complete.
Al.

[tcmachine402]

My bad, i should have known that.