Bridgeport Series 1 MDI Conversion

**Gary** · 03-01-2019

I bought some bar stock and made them myself. not that hard.
Or modify the existing pulleys to fit on the new motors.

Originally Posted by Chaz

Hi,

The pulleys are 12 (X and Y) and 13 (Z) respectively. H pitch. Beltingonline are telling me they can have them made to order but warned that they will be pricy (I need to send them some pics) as I've suggested that maybe I just bore them out and install a grubscrew.

In terms of costs, sure, I dont want to spend more money than I need but I could get this machine running on steppers for a lot less money, that's not the point here.

If the DMM stuff isnt much better or doesnt offer more than perhaps an easier fitment, then I might as well save the money and use that for a better touchscreen / PC whatever. I'm not trying to cheap out on the build but dont see value in paying for something that doesnt offer better. Of course the law of diminishing returns persists too.

As an example I have Panasonic drives and motors on Thor and cheaper Chinese stuff on my old Triac. The Triac worked OK but no doubt the Panasonic stuff is better. The only reason I bought them was that I got some stuff at good prices from an Ebay seller. I wont pay RRP or similar for Panasonic.

I can get away with a 750W system, been avoiding it due to mounting concerns, bracketry might be OK, motor shaft diameter and length are the main concerns. One guy on Youtube has basically extended his motor shafts to suit.

**swarf-boy** · 04-01-2019

Just been checking out your acorn control.
Interesting unit. Quite a lot in the Kit.

Options seem to get strangely pricey though
( $45 for a dual circuit E-stop, being a stand out).

See those 4 series drives look to have built in S curve feature.
Didn't know that was a feature in drives. ( every day is a school day, as they say).

**Chaz** · 04-01-2019

Originally Posted by swarf-boy

Just been checking out your acorn control.
Interesting unit. Quite a lot in the Kit.

Options seem to get strangely pricey though
( $45 for a dual circuit E-stop, being a stand out).

See those 4 series drives look to have built in S curve feature.
Didn't know that was a feature in drives. ( every day is a school day, as they say).

Yep, mine was ordered on Wednesday, import tax is a bit harsh, might be delivered today or Monday latest.

I have some potential Panasonic servo motors sorted, will check over the weekend and see if they will work then i need to sort out mounting / pulleys.

**Chaz** · 06-01-2019

I'm trying to decide what motor to go for.

80 Size - 19mm shaft but 35mm long.
90 Size - 16mm shaft, same length.

Both those have near identical specs.

110 Size is almost a direct replacement but the shaft is 19mm and longer which is I think is ideal. This is for a 1.5 KW setup, around $100 per setup more expensive (not much of a concern).

Which would you go for?

**swarf-boy** · 06-01-2019

Lots of consideration to take into account.

My machine worked well with the original motors, (it was fully functional on 3 phase when purchased). As previously mentioned, I was also very conscious of electrical max demand of finished machine, as well as keeping running costs reasonable.

The 1.5KW version might have been a choice otherwise, as you could just pull the rotors out of the motors and machine the shaft ends down.
Or fit different pulleys, as mine are tapered collet type. Having said that, I could probably bore out originals and broach a key way in to fit those 19mm shafts. Extra length makes no difference on Z or Y on my Interact. Your MDI has a longer X axis cover for the manual handles, so it may make no issues there either.

Only things that may catch you out is the rotor inertia and the possible effect of having so much Torque. ( although you might find a 4NM version in 110ST.

I partly figured that if my 90st 4NM versions ended up being too small in the end, I could always use them on the next project ( cnc lathe).

Guess its all a gamble really. The only good thing ( in my view) is that as they are 220V AC, there is no need for huge power supplies and torriods. Time will tell

Mark.

**Chaz** · 06-01-2019

Originally Posted by swarf-boy

Lots of consideration to take into account.

My machine worked well with the original motors, (it was fully functional on 3 phase when purchased). As previously mentioned, I was also very conscious of electrical max demand of finished machine, as well as keeping running costs reasonable.

The 1.5KW version might have been a choice otherwise, as you could just pull the rotors out of the motors and machine the shaft ends down.
Or fit different pulleys, as mine are tapered collet type. Having said that, I could probably bore out originals and broach a key way in to fit those 19mm shafts. Extra length makes no difference on Z or Y on my Interact. Your MDI has a longer X axis cover for the manual handles, so it may make no issues there either.

Only things that may catch you out is the rotor inertia and the possible effect of having so much Torque. ( although you might find a 4NM version in 110ST.

I partly figured that if my 90st 4NM versions ended up being too small in the end, I could always use them on the next project ( cnc lathe).

Guess its all a gamble really. The only good thing ( in my view) is that as they are 220V AC, there is no need for huge power supplies and torriods. Time will tell

Mark.

Thanks. Good points. Torque can be limited. I'd rather have too little than too much - that said, is rotor inertia a real concern?

Thheir 0.8 KW is 2K RPM, the 1.2 has the same rotor inertia. The next one down is 0.6 KW, so too small in this frame size.

**Chaz** · 10-01-2019

In the end I was able to get some Panasonic stock from the supplier of my previous kit used on my other mill (Thor)

I will have 2 x 0.75KW and 1 x 1.0KW available. Ill likely install the 1.0KW setup on Thor and then have the same three for the Bridgeport.