Bridgeport Series 1 MDI Conversion

[Chaz]

In terms of shafts, yes 5/8th of an inch, smooth (the pulley has some form of compression system) and around 55mm long, much longer than most shafts.

You can find some more information about your existing motors in the attached document.

Thanks, I found the same document, hence where I saw the details regarding the motors.

The motor specs are 0.65KW, 3100 RPM, 2.9 NM stall.

The physical measurements are different however. Shaft sizing is different. Ill measure the motor up tomorrow properly.

[Chaz]

So Ive done some measurements and mocking up of the existing measurements for the motors etc. This will make finding a suitable motor setup a bit easier and of course will then be the basis of my measurements for any brackets I need to machine.

Existing Bridgeport mounting shown in glass to help with visualising.

[Chaz]

And superimposing a Servo motor I am looking at which is a 1 KW unit. The biggest problem is I cannot find 12 and 13 pitch H Belt Pulleys, only 14 and larger. Ill speak to a supplier I use.

For the Z axis I'd probably be inclined to widen the mounting circle to allow for the servo to sit flush instead of on its 'rim'. I can do this is my existing missing machine.

[Chaz]

Excellent service from Centroid. 2nd Acorn and MPG ordered, looking forward to receiving it in the next few days. Ill use it to test some lathe macros (instead of removing the one I have on the lathe) whilst I finalise my motor choice / purchase for the mill.

[Chaz]

I managed to get a quote from DMM. Great company, quick response.

They have a Nema 42 replacement motor (fairly new, released a few weeks ago). My motors (According to them) are Nema 42.

The ones they are proposing are same shaft size which is very helpful (5/8th inch) as I am struggling to find direct replacement pulleys with 12 and 13 teeth respectively (14 is minimum generally).

The issue is the motors are not a perfect fit (mounting holes are a bit different - 75 PCD vs 82 PCD, probably minimal effort to sort this but they are fairly pricy and potential import tax from Canada. These are 1.3 KW servos, running off 220V (so high volt feed). Including 3 meter encoder and motor cables plus the Acorn DB 25 cable and programming lead, these work out at around $700 ish per axes.

I know the stuff from BST Automation and other sources listed are cheaper. Id like to have as little mechanical fuss / changes to make this all work (most seem to have 19mm pulleys), so modifications will be necessary but it looks like exact like for like change, so mods will have to be done anyways.

Thoughts?

[martyscncgarage]

I managed to get a quote from DMM. Great company, quick response.

They have a Nema 42 replacement motor (fairly new, released a few weeks ago). My motors (According to them) are Nema 42.

The ones they are proposing are same shaft size which is very helpful (5/8th inch) as I am struggling to find direct replacement pulleys with 12 and 13 teeth respectively (14 is minimum generally).

The issue is the motors are not a perfect fit (mounting holes are a bit different - 75 PCD vs 82 PCD, probably minimal effort to sort this but they are fairly pricy and potential import tax from Canada. These are 1.3 KW servos, running off 220V (so high volt feed). Including 3 meter encoder and motor cables plus the Acorn DB 25 cable and programming lead, these work out at around $700 ish per axes.

I know the stuff from BST Automation and other sources listed are cheaper. Id like to have as little mechanical fuss / changes to make this all work (most seem to have 19mm pulleys), so modifications will be necessary but it looks like exact like for like change, so mods will have to be done anyways.

Thoughts?

I personally like DMM and have worked with them.
I am working on a Clausing Kondia knee mill with the same servos.
If you have the original pulleys you can roll with them. If you can belt at 1:1 you should have no issues either.
My .02
Marty

[Chaz]

So interesting discovery.

I was told the encoders had been changed to AMT 102 but the encoders are Heidenham ROD450B. I was tempted to take the covers off to check the encoders but thought to leave it, no point in messing with it, was just keen to test the encoders in case I want to sell the motors / encoders.

Cable was new .... that was interesting.

Fast forward to today, I get a response email from the previous owner. Turns out the AMT 102 are mounted but they used the original covers, so we have 3 decent DC motors with modern encoders.

I'd got pricing and meant to be ordering a replacement servo system tonight. I could get these working with cheaper drives but would prefer to replace all of it in one go, so yes, these motors / encoders will come up for sale once I have replaced with servos.

[Chaz]

Someone else doing a retrofit in the UK will also have his motors up for sale, they have original encoders / resolvers, interested?

[martyscncgarage]

Ah, you are on the other side of the pond.... probably won't work for me. I recently acquired 4 Centroid motors and are on the shelf now.

Marty

[Chaz]

Ah, you are on the other side of the pond.... probably won't work for me. I recently acquired 4 Centroid motors and are on the shelf now.

Marty

Thanks, indeed, my concern was the shipping cost but I assumed you had worked out that we were UK based