[mactec54]

Hi MARKG
Thanks for your kind remark's,not many have realised what I really had done with the Bridgeport heads I have rebuilt

To be able to run at the 120Hz which will give you around 6000rpm,at 1/1 all the bearings have to be in good shape, or new in the head, the motor you should rebuild with good quality bearings (NSK/SKF Etc) & balance the motor is a must, the stock motor is 3450rpm so is quite easy to get it to the 6,000rpm @ 120Hz after being balanced, with your pulley mounted

Yes Mark the mod's made to this head were all related to getting a nice smooth/high speed running spindle, the back gear was removed as well in this head, this allowed 5" to be taken out of the top & 3" off the motor shaft, I could of taken more off the motor shaft, but I had already balanced it, so left it at that, I have run these as high as 12,000
with a 2/1 pulley set

The only problem is with the spline's that drive the spindle, this long shaft gets a wobble on it, so I mounted a solid piece on top of the splines that slides up & down inside a bushing in the piece that mounts on top of the disc brake this takes care of that problem

With removing the back gear you lose any ability to be able to cut heavy duty stuff at low speed

It is still very good down to around 800rpm/1000rpm with the 1/1 pulley set without the backgear

If you need low speed torque for cutting then you need to have a 2 pulley set 1.5/1 or a 2/1 set as well as the 1/1set
to get good cutting at low speed

[polaraligned]

Hi MARKG
Thanks for your kind remark's,not many have realised what I really had done with the Bridgeport heads I have rebuilt

To be able to run at the 120Hz which will give you around 6000rpm,at 1/1 all the bearings have to be in good shape, or new in the head, the motor you should rebuild with good quality bearings (NSK/SKF Etc) & balance the motor is a must, the stock motor is 3450rpm so is quite easy to get it to the 6,000rpm @ 120Hz after being balanced, with your pulley mounted

Hmm....My 1.5 hp J head is 1740 rpm, and both of my BOSS heads are 1700 rpm. How did you get a 3450 rpm motor?

The only problem is with the spline's that drive the spindle, this long shaft gets a wobble on it, so I mounted a solid piece on top of the splines that slides up & down inside a bushing in the piece that mounts on top of the disc brake this takes care of that problem

So the top of the spindle has a round piece attached to the top. This round piece rides (spins) in a bushing, and also moves up and down 5" as the quill moves up and down. So the top of the spindle shaft is supported from whipping and still is allowed to move up and down. Am I getting this?
Any chance of a pic?
Trying to visualize what you did...

Thanks Mactec.
Your head rebuild is a work of art....If I could only do the same.

[mactec54]

Hi polaraligned

All the Boss 5&6 I have seen have the 3450 2Hp motor so I'm not sure if they were an option or not, I Know some were 2 speed too, look on the name plate & see what you have got, Your 1-1/2 Hp motor, I have not seen that on the Boss machines

[TOTALLYRC]

My BTC-1 is 3450 and so is my spare manual J-head.

Mike

[polaraligned]

Hi polaraligned

All the Boss 5&6 I have seen have the 3450 2Hp motor so I'm not sure if they were an option or not, I Know some were 2 speed too, look on the name plate & see what you have got, Your 1-1/2 Hp motor, I have not seen that on the Boss machines

My Boss 4 and Boss 6 machines have identical 2hp motors that clearly state on the label that they are 1700 rpm at 60 hz. My manual 1-1/2 hp j-head says 1730 rpm.

Being 3400 rpm makes a lot more sense to me. After all, there is no gearing in the vari-drive to double the speed. They must be 2 speed motors and for some reason they labeled only the lower speed.

[polaraligned]

Thanks Scott,

I have run it to about 120 hz and it didn't sound happy so I have settled on 80hz (120% or about 2400 rpm) for now.

Mark,

Your stock vari-drive will run up to 4k rpm. I would think you should easily get your conversion up to that speed. Especially in light of the fact that you took a lot of dead weight off of the spindle top. Maybe you need to check your bearings....

Now your 60hz speed tells me that you have a motor much slower than 3400 rpm. Now I am scratching my head.

On edit:
when you say you run it at 2400 rpm do you mean the motor or is 2400 at the spindle?
If you mean the motor, then if the vari-drives up-gear 2.5:1 that would be a spindle speed
of 6000 rpm.

[polaraligned]

My BTC-1 is 3450 and so is my spare manual J-head.

Mike

I just read in another post of yours that you state "most j-heads that you have seen are 1725 rpm".

The BTC-1 was designed for higher speeds so that explains the motor on it.

I am thinking, but not 100% sure, that 1700 rpm was the j-head norm.
I see no reason to believe that the motors on my BOSS-4 and BOSS-6 are 2 speed motors, or mis-labeled.

The j-head vari-drive may be capable of a 2.5:1 "up gearing". That puts you right at 4200 rpm at the spindle.

[mactec54]

Hi polaraligned
Here is the spec of Boss machines we are talking about, the original spindle speed was 4,200 so you were not getting that from a 1700 rpm motor so they had to be running the 3450 motor to get those numbers

[polaraligned]

The vari-drive is capable of gearing up 2.5:1 and also gearing down 2.5:1. Visualize how it works. It gears up or down.

So a 1700 rpm motor will be capable of covering the high speed range of 500 rpm to 4200 rpm.
With a 3400 rpm motor you would need to gear down 6.8 to 1 to achieve the low end of the high speed range. Now that is not going to happen with a varidrive. But if the Varidrive multiplies the speed (1700) by 2.5 or divides by 2.5, then the whole high speed range is covered.

The low speed range is 60 to 500 rpm and uses a back gear that has a 8.92:1 ratio. (according to my manual).
To achieve the top of that range, the varidrive MULTIPLIES the motor speed my 2.5 then divides it by 8.92 to achieve the 500 rpm's. The varidrive DIVIDES the motor speed by 2.5 then again by 8.92 to achieve the bottom of the range.

So the math points to a 1700 rpm motor NOT a 3400 rpm motor as being the correct motor. My motor tags appear not to be lying.

[polaraligned]

OK. To add to this.
Look on page 3 of the BP M-105H manual that is available at various places for download including here:
http://www.neme-s.org/Shaper%20Books...20Maintain.pdf

It tells you that ALL "J" and "2J" heads were 1800 rpm motors, except a hi-speed "J" head that used a 3600 rpm motor.

The BOSS machines were just modified J heads. When I rebuilt both of mine I used standard 2hp parts. So everything points to my motor labels being correct as to the BOSS machines using the slower motor.

[mactec54]

Hi polaraligned

Not correct all the Boss 5/6 machines even the one with the J type head, had the high speed motor, it seem someone has done some switching around in your case, the Boss series is a total different machine from the manual machines that's in your PDF file, even though some of the parts are the same

Now if you had a very early Boss from the 70s then you may have a low RPM motor which had a step pulley drive But you are talking about a Boss 5/6 which is a very different machine

[TOTALLYRC]

I just read in another post of yours that you state "most j-heads that you have seen are 1725 rpm".

The BTC-1 was designed for higher speeds so that explains the motor on it.

I am thinking, but not 100% sure, that 1700 rpm was the j-head norm.
I see no reason to believe that the motors on my BOSS-4 and BOSS-6 are 2 speed motors, or mis-labeled.

The j-head vari-drive may be capable of a 2.5:1 "up gearing". That puts you right at 4200 rpm at the spindle.

Hi Polar,
That is true that most J-heads that I have seen are the low speed variety but I was just pointing out that the high speed versions do exist.
My spare head has the rpm tag that is double what my standard j-head
had.
The BTC-1 was designed for 5k rpm so it has the 3450 motor a slight overdrive on the pulleys and a 2 speed gearbox to allow for low speed work.

Mike

[polaraligned]

the original spindle speed was 4,200 so you were not getting that from a 1700 rpm motor so they had to be running the 3450 motor to get those numbers

Oh no?,
I dropped the fan cover of my motors today and put a tach on them....1780 rpm's.
Guess what the spindle speed was when I cranked up the varidrive?....Well, it was 4200 rpm's.
Of course your are getting 4200 rpm's. How the hell did all the manual J-heads all do it with 1700 rpm motors?
Bottom line is that the BOSS heads are the standard varidrive design modified for the BOSS machines. The varidrive design is the same. I confirmed this with an ex BP field service tech.

[mactec54]

polaraligned

You did not say you had a varidrive on your machine the PDF you put up was mostly for a step pulley head which will not do 4,200 with a 1740/ 1780 motor, & yes most of the varidrives are close to all being the same which are around 2.3-1 ratio

So if you have a VFD drive on your machine running at 1-1 then you can only get around 3,500

You can get 6,000 easy with the 3450 motor at 1-1 on the standard Boss 5/6 machines

[MARKG]

Mark,

Your stock vari-drive will run up to 4k rpm. I would think you should easily get your conversion up to that speed. Especially in light of the fact that you took a lot of dead weight off of the spindle top. Maybe you need to check your bearings....

Now your 60hz speed tells me that you have a motor much slower than 3400 rpm. Now I am scratching my head.

On edit:
when you say you run it at 2400 rpm do you mean the motor or is 2400 at the spindle?
If you mean the motor, then if the vari-drives up-gear 2.5:1 that would be a spindle speed
of 6000 rpm.

Sorry for not responding earlier, I thought I was subscribed to this thread but obviously was not. DOH!

Yes, the motor on this Series 1 machine is a 2hp 1710 rpm at 60Hz, so the numbers I quoted were right, at 80 Hz I am getting 2200 rpm and change (at the motor and spindle due to my 1:1 home made pulley combination) and this verified just now with a SnapOn optical/digital tach.

To save you some math, with this setup (1:1) I should get:

100Hz would be 2850 rpm motor and spindle
120Hz would be 3420 rpm motor and spindle
150Hz would be 4275 rpm motor and spindle
180Hz would be 5130 rpm motor and spindle
200Hz would be 5700 rpm motor and spindle

After the information provided by mac, polar and others, I am now tentatively running this old gal to 90 hz (motor at 150% of its rated speed) , the attached photo is a reading of spindle speed measured and calculated by the VFD (24.5 rpm/Hz) . The error is about 4%, good enough for what I'm doing.

I will up it slowly over the next couple of weeks 'til either the machine or I get the shakes....from what mac says and I do not dispute it, it would appear that a precision motor reduild may be required to be able to push this 1:1 1710rpm motor arrangement to 120 Hz (200%) and beyond.

Anybody's thoughts on the wisdom of even attempting this are welcome.

Mark

[polaraligned]

Yes, the motor on this Series 1 machine is a 2hp 1710 rpm at 60Hz

And your machine is a BOSS 6 looking at the video you posted. Your motor is the same as both my BOSS motors. I don't know how Mactec got 3450 rpm motors, but I cannot find ANYONE who has these faster motors on a BOSS machine. I even called several used BP parts dealers. All have the same 1710 motor. I am quite certain that 1710 rpm is the correct stock motor.


My options are (at this point) pointing me to replacing the stock motor with a 3 to 5 hp inverter duty motor rated for 5400 rpm safe RPM. Not cheap at $500, but allows a 1:1 drive ratio with decent lower end torque.

If not for increasing the spindle speed I see no reason otherwise to remove the varidrive.

Best of luck.

[mactec54]

Hi MARKG

You should never go over 120Hz with your standard motor, if you want to get higher rpm you will have to have a another pulley set to get up to the higher rpms with the 1700 motors, Like 1.5.1 or even 2.1, if you want low rpm as well as high rpm I would not go over the 1.5.1

polaraligned if your varidrive is in good shape there would be no need to change it, just when everything gets worn out

As for motors Boldor have some good inverter duty motors, the washdown pump motor
which are good for 6,000 is a good choice

[MARKG]

Right, I'm not familiar with what an inverter duty motor is, can you or someone please elaborate?

Many TIA

Mark

[mactec54]

Hi MARKG

Inverter duty
Inverter Drive Motors are wound with 200 degree C. moisture resistant ISR (Inverter Spike Resistant) magnet wire which dramatically extends the life of the motors compared to motors wound with non-ISR wire. These motors are designed for applications where up to a 1000:1 constant torque speed range is required.

[polaraligned]

Inverter duty can run much slower than standard duty motor without overheating. They also are able to withstand the voltage spikes of a VFD better.
There is also Vector duty motors which are designed specifically for use from a VFD. They often are available with encoders for sensor feedback to the VFD.