[alex 850]

i have a series one boss 5 mill. i want to change the drive system to solid pullys and a electronic varible speed controller. can anyone tell me what size pullys and tensiner and where to order them from.it has the adjustable pullys with the mill now and it is to weak this will be the 3rd rebuild.
thanks alex

[nate]

Not to be rude, but if its the third rebuild, isint that telling you that you are exceeding the capability of the bridgeports head?

Mabie you should look at upgrading the mill to a more robust unit.

Also, I'm curious what kind of work you are doing that eats the variable speed parts?

[alex 850]

this mill is a weak design from the factory! i am cutting knife parts very simple cuts for this machine. so you have no info to offer correct?
thanks alex

[SCzEngrgGroup]

this mill is a weak design from the factory! i am cutting knife parts very simple cuts for this machine. so you have no info to offer correct?
thanks alex

What Nate was suggesting, quite correctly IMHO, is that it is NOT a "weak" design, which suggests that something *else* is wrong that you have not fixed in the three previous rebuilds. Either you've got some worn part or other problem that is *causing* the premature failures, or you're over-taxing the machine. The basic design is perfectly sound, and quite robust, and what you're experiencing is not normal.

Regards,
Ray L.

[nate]

I wish I did have "info to offer"

I was simply pointing out that if the machine "as built by the factory" is not sufficient, then looking at a different machine may be in order.

That said, i'm all for modifying the machines I own when needed...

[mactec54]

Hi alex 850

nate the variable speed drive is not the greatest in these heads with the plastics bushes
can wear out quite quick

alex it's not that hard to change, what you want to do, the most problem you have is to tension the belt there is almost no ajustment, so you have to add some by sloting the flange of the motor mount,I will post some photos on here you can also see them in my photo gallery

[alex 850]

thank you !i knew thbat i was not crazy! i have replaced those bushing and had good mechanics help with the rebuild .i saw a post here a while back where some body converted theres over because of the noise.
thanks alex

[mactec54]

Hi alex 850

Here are some photos, you won't have to do your head like this, these were special heads I built for some customers, the heads have 5" taken out of the top so it will look different to your head, the motor shaft you can see that has 3.250 off this one I could of taken 1'' more off it but I was going to make some more pulleys for higher speeds, I did do one that runs at 12,000 this one runs at 6,000 so the extra pulleys are 2-1 this one in the photo is 1-1 the belt is a poly-v belt

[alex 850]

the head did throw me off. so you made all of these parts. how much would you charge me to get this setup from you for pulleys and everything else.
thanks alex

[bugattiman]

Hi Martec, I am very impressed with yuor bridgeport head conversions. I see the motor is inverted compared with the position of my 2J2 head. Is this necessary or can it be left in the above position?

I am looking at doing away with the troublesome vari drive and plastic bushings which are giving me giref continually.

I have been advised to have a separate fan cooling the motor also?

I have a vfd and basically would need to make the pulleys and purchase a poly v belt. I'd like to go for an 8" pulley on motor and 4" pulley on spindle to achieve higher revs as I rarely do any heavy work on the machine. It's normally, cutting aluminum,brass,plastic or rarely steel.

Can I still retai nthe back gear and brake drum set up?

any help \ drawings very much appreciated, best regards,

Bugattiman

[mactec54]

Hi Martec, I am very impressed with yuor bridgeport head conversions. I see the motor is inverted compared with the position of my 2J2 head. Is this necessary or can it be left in the above position?

I am looking at doing away with the troublesome vari drive and plastic bushings which are giving me giref continually.

I have been advised to have a separate fan cooling the motor also?

I have a vfd and basically would need to make the pulleys and purchase a poly v belt. I'd like to go for an 8" pulley on motor and 4" pulley on spindle to achieve higher revs as I rarely do any heavy work on the machine. It's normally, cutting aluminum,brass,plastic or rarely steel.

Can I still retai nthe back gear and brake drum set up?

any help \ drawings very much appreciated, best regards,

Bugattiman

The inverted Motor placement was standard for the Boss Machines, even though they looked and used most of the same Head parts as your machine

Yes you can retain the Back Gear, how fast do you want to run??

You can with your VFD run to 100Hz on the standard motor you may be able to go as high as 120Hz, but with your country being 50Hz I would stick with 100Hz , if the motor is happy at 120Hz, then not problem, this will double the motor rated RPM, you can of cause change the motor for a higher RPM motor, and with the VFD you would not need such a high pulley ratio to get the speeds you want, you will loose a lot of torque at the spindle when you use a pulley ratio like this

[bugattiman]

Hi mactec54, thanks for responding so quickly. I would say 5,000 rpm as a max and I do not do any heavy work so to speak. I suppose a job like a cylinder head skim with a large flycutter is worst I'd be doing and I only take max 0.2mm cuts with a single point fly cutter so don't think torque would be an issue. I have a CNC miller I can run at 4,200 rpm and I have also made an attachment to hold a water cooled spindle that can get me up to 24,000 rpm for small cutter work like engraving etc. The main reason for wanting to convert is the noisy vari head and I don't particularly like the system of the speed changing. So are you saying the motor needs to be inverted or can it be left in its overhead position? Height is not an issue in my garage, cheers

[mactec54]

Hi mactec54, thanks for responding so quickly. I would say 5,000 rpm as a max and I do not do any heavy work so to speak. I suppose a job like a cylinder head skim with a large flycutter is worst I'd be doing and I only take max 0.2mm cuts with a single point fly cutter so don't think torque would be an issue. I have a CNC miller I can run at 4,200 rpm and I have also made an attachment to hold a water cooled spindle that can get me up to 24,000 rpm for small cutter work like engraving etc. The main reason for wanting to convert is the noisy vari head and I don't particularly like the system of the speed changing. So are you saying the motor needs to be inverted or can it be left in its overhead position? Height is not an issue in my garage, cheers

No the motor does not need to be inverted, but would make it easier to install the belt J8 is the best in the poly V Belt which means 8 ribs a J6 will do the job but are marginal

[mactec54]

Hi alex 850
I used to build them 5 at a time, but the cost is very high, You can do this yourself, not the same but will work almost as good, I could walk you through it & it should not take very long to do.

The head you see has a disc brake, there is many things that you can't see that were changed, that is why I say you can do it with what you have.
This is a photo of the brake setup

[colin1544]

Hello Mactec I would be most interested to here of your rebuild and any drawings you may have that you would like to share even at a resonable cost to do a 1-1 conversion as My machine sits very close to the ceiling of my workshop and it would help to loose a couple of inches off the height. Cheers Colin

[mactec54]

Hi colin1544

I would be glad to help anyone that wants to do a conversion, this can be simple or very complex, I would suggest the simple, which involves very little change to the machine to do this,

The one in the photos I still have, This was the last one I did just over 10years ago, it still looks as the photos do & runs production 4/ 6 days a week,

In your case were you want to take some out of the top, would take a little more than someone who just wants a straight 1-1, you would only have 4 parts to machine on the head plus the new pulleys if you make them

[colin1544]

Hello
again Mactec the simple one sounds OK does the 4 parts to machine include the brake system, as I like the looks of that, as I finnished up on my machine at the moment just putting a fixed spacer in between the pulleys which works OK but I still get the rattle on the head as I think the origonal varispeed belt is worn in places. So the polyvee belt system looks good as when I used this type of belt on another project some years ago it was alot smoother and quieter spindle. Talking about your brake system do you use one of the origonal pulley sheaves in your mods and does the air brake hold the spindle OK when doing a tool change on the Bristol Erickson quick change toolholder.
Look forward to your coments and any other photos you may have, Cheers Colin

[underthetire]

AC Pro drive. They work very well, more RPM, much smoother. Guy builds them and ships them out. Even has a Z scale with DRO built in.

[mactec54]

Hi colin1544

No the disc brake is totally custom, there are no Bridgeport parts in the upper drive area
the low gear also was removed, what machine do you have, a photo of your head would be good.

The brake holdes very well for doing up & undoing the Eichson quick change

I will try & put some more photos with captions this may help for you to see how it was all put together, this will take some time to do

On the motor shaft you should only have a pulley

The front bottom pulley sheave is part of your standard Bridgeport brake, so the simple build will still have to keep this, but it may need to be modifided to lock it on the main spindle shaft, if it can wobble around then it will make noise, the other place noise can come from is in the splines that drive the spindle, but heavy grease can help this

[otpco]

I have a Bridgeport Moog !!! Mach convert . ball screws , servos, etc and am finding the head drive ordinary to say the least . I have replaced the delrin Bushes and key on the motor , belt , ant will now take a look at the other end (quill ) The tool changer is still work in progress .I have air cylinder to replace the Hydrolic thing . I am also looking at the vdf chage to plain pulleys and some sort of speed control .Via the Vdf . any ideas out there would be good someine surely done this before me . Thanks to all lets enjoy this new year and make lotsa mess .