[davek0974]

Nice

Ok so servos are getting the thumbs-up here. What sort of size do i look for here? 400W, 1kw, 1.5kw?

S1 Boss' seem to be very rare here, typical when you want something.

As for pulling the VS, might be easier to get a fixed pulley head

My original BP motor has been running fine on a VFD for a few years now, loves it.

[mactec54]

Nice

Ok so servos are getting the thumbs-up here. What sort of size do i look for here? 400W, 1kw, 1.5kw?

S1 Boss' seem to be very rare here, typical when you want something.

As for pulling the VS, might be easier to get a fixed pulley head

My original BP motor has been running fine on a VFD for a few years now, loves it.

A Boss 1 is the first one they made, you don't want anything less than a Boss 5, if you are going with a CNC ready machine, most before the Boss 5 are warn out, so try to find one that a tech school has had

Stay with your first thoughts, with the Dmm AC servos, anything else that has been suggested does not compare, 1Kw would be ridiculous on one of these machines, I have built more than 30 of these Boss type machines, and 750w works perfect at 1:1 the standard gear ratio of the Boss 5, I have changed some of the Z axes to 2:1 on some of the Boss 5 machines, a Boos 6 already has a 2:1 ratio on all axes

There is also nothing wrong doing a manual machine, Hiwin Ballscrews Kit, is the best choice for these machines, start with just converting the X & Y axes, then you can make the Z axes mounting plates Etc

[davek0974]

Thanks Mactec,

The ballscrews are the hardest part - there are no UK suppliers of kits, I would want a kit as messing around with the dog-bone mount is not something I would want to do, this would mean finding an import source, have you any links to the HiWin stuff??

I will also need some end plates as I want to get rid of the old 6F power feeds I have on X&Y.

The main restriction on ANY donor machine is the height - this cannot be any taller than a standard BR2J2 manual machine, maybe 2-3" max then it would not fit in the shop

I was guessing on 2:1 reductions for servo drive, I cant see much point in blistering rapids on an old machine.

[mactec54]

Thanks Mactec,

The ballscrews are the hardest part - there are no UK suppliers of kits, I would want a kit as messing around with the dog-bone mount is not something I would want to do, this would mean finding an import source, have you any links to the HiWin stuff??

I will also need some end plates as I want to get rid of the old 6F power feeds I have on X&Y.

The main restriction on ANY donor machine is the height - this cannot be any taller than a standard BR2J2 manual machine, maybe 2-3" max then it would not fit in the shop

I was guessing on 2:1 reductions for servo drive, I cant see much point in blistering rapids on an old machine.

Here is a Kit on Ebay these are a C5 grade Ground Ballscrew which you don't want any less than a C5 Grade, also they are made for each Bridgeport model so these may be the wrong length for you machine

A UK Ballscrew supplier as well

Lead screw and Ball Screws Moore-international.co.uk

Bridgeport Knee Mill ballscrew Set 12" x 48" w Yoke Precision Ground New | eBay

[davek0974]

Thanks for that, great info, price is good too.

Will contact the UK one on Monday and see what they offer.

[davek0974]

Ok, so the front mounted screw is the most popular, 1605 or similar seems to be the way.

The motors I am looking at are 750w AC servo, I was thinking of just ordering a set of three as the price is really good and the smaller motors (for the Z) seem to cost more.

My main concern here is having 750w of motor and probably 2:1 drive on the Z axis, transmitting all its power through the one bolt into the front of the quill. Is there a way to help prevent damage - motor current limiting etc on a servo ?

Are things like table & quill locks removed as well?

[mactec54]

Ok, so the front mounted screw is the most popular, 1605 or similar seems to be the way.

The motors I am looking at are 750w AC servo, I was thinking of just ordering a set of three as the price is really good and the smaller motors (for the Z) seem to cost more.

My main concern here is having 750w of motor and probably 2:1 drive on the Z axis, transmitting all its power through the one bolt into the front of the quill. Is there a way to help prevent damage - motor current limiting etc on a servo ?

Are things like table & quill locks removed as well?

The motor you can control, normally in your software,with Acceleration and Velocity settings, plus the Drive has safeties, for over amp voltage etc, they will trip before, it would break or damage the bolt, the quill lock you can remove the whole thing, but it can also be useful to take up any clearance in the quill housing, I would remove the little handle/lever on it though, and just use it finger tight, the X & Y axes yes just put a plug in those, unless you need to do the same as the quill

[davek0974]

Thanks, I am just exploring the options after looking over the mill with a tape measure

Those plans will certainly help but i'll likely go with an option that does not need the housing being split, motor drive on top.

Will motorise the knee later on just because hand cranking it is a *****

[mactec54]

Thanks, I am just exploring the options after looking over the mill with a tape measure

Those plans will certainly help but i'll likely go with an option that does not need the housing being split, motor drive on top.

Will motorise the knee later on just because hand cranking it is a *****

Yes it does not have to be mounted like that, there are many options for mounting the top support plate, you can remove the gearbox cover on the side of the head and mount from there, all the gears would be removed or disabled anyway