Fobco Star Restoration

[Co1]

Picked this up for £90 today, which I thought was a bit of a bargain. I’m working away from home at the moment, so the plan is to take a bit with me and fettle it in my digs to save me going to the pub every night!

Couple of problems straight off the bat:

It’s three phase and I really need to convert it as I don’t fancy running it off an inverter, I want to keep it simple.

Second issue is that I can’t get the head to slide down the pillar, or to move at all. It’s totally seized. Any thoughts or tips?

 

[Phill05]

Take off the pulley cover on top, run some WD40 around the shaft.
Release the locking leaver for the head and tap the bolt in to release spray some oil in, leave the leaver locked below to stop the head from slipping down, then block the base from turning and try moving the head left to right it should ease it spray some more oil around and you should get some up and down movement.

You can pick up a single phase motor easy and reuse the switch.

 

[Co1]

Thanks Phil, that worked a treat.

The base, table and pillar need a good degreasing and cleaning. What do people think about sticking them in the dishwasher?! The wife is away next weekend, so she’ll never know…

 

[Phill05]

"so she’ll never know"
You want to bet on that!!!

Pick up some Citric acid that will sort it out for you.

 

[flh801978]

Once you have used a drill with variable speed you wont want to back…
No removing belt cover and slackening belts
Always right speed for the drill in use
A vfd is only £50 or less..protects the motor will run in reverse also

Ian

 

[Co1]

Once you have used a drill with variable speed you wont want to back…
No removing belt cover and slackening belts
Always right speed for the drill in use
A vfd is only £50 or less..protects the motor will run in reverse also

Ian

I haven't to found one that cheap. Where are you looking?

 

[Sideways]

Once you have used a drill with variable speed you wont want to back…
No removing belt cover and slackening belts
Always right speed for the drill in use
A vfd is only £50 or less..protects the motor will run in reverse also

Ian

Rubbish.

A VFD is no substitute for changing belts.
Dial it down to 1/4 speed and you only have 1/4 the power.
You have none of the torque increase that you get from downgearing through the pulley ratios and which you need to twist a large diameter cutter in a drill.

I'm not knocking VFD's, I'm a fan and almost all my machines are driven with them, but the answer above suggests a lack of understanding of how they work and their limitations.

A 40mm Forstner bit needs a good deal of torque behind it.

 

[Sideways]

You can pick up a single phase motor easy and reuse the switch

I imagine with the age of a Fobco star, it'll be an imperial size motor so you can't just swap in a modern metric one without modifying the mount and boring or sleeving the motor pulley.
You should still be able to get a single phase imperial easy enough but you may have to pay a bit for it.

 

[Co1]

Thanks sideways. It is indeed imperial, I’ll keep my eye out on eBay.

 

[Fergie 307]

Rubbish.

A VFD is no substitute for changing belts.
Dial it down to 1/4 speed and you only have 1/4 the power.
You have none of the torque increase that you get from downgearing through the pulley ratios and which you need to twist a large diameter cutter in a drill.

I'm not knocking VFD's, I'm a fan and almost all my machines are driven with them, but the answer above suggests a lack of understanding of how they work and their limitations.

A 40mm Forstner bit needs a good deal of torque behind it.

Couldn't agree more.
No problem with using a vfd to run it but you want the torque to increase with slower speeds, exactly what you get from moving the belts.
Using variable speed from the vfd to slow it down does exactly the opposite.
So use a vfd by all means to be able to run it off single phase, but still use the pulleys to change speeds.

 

[Fergie 307]

Thanks Phil, that worked a treat.

The base, table and pillar need a good degreasing and cleaning. What do people think about sticking them in the dishwasher?! The wife is away next weekend, so she’ll never know…

Don't do it!
Different grease, all you will probably do is cover the inside of the dishwasher with gunk.
And she will most definitely know

 

[kinverkid]

I'm hoping you are going to regularly update your progress. I'd like to follow how the restoration goes.

 

[flh801978]

Hmmm its funny i spend all my working days working on motors and VFD's on small to massive machines > 5 million£

I guess i missed out the line once you have chosen a suitable belt ratio then the VFD will suit
i'm not suggesting that you can go from 1mm in hardwood to 75mm with the twist of a dial
but if its for wood the 2nd slowest ratio will suit from 20hz to 100 hz (so 200 rpm to 2000 rpm)
if metal the 1st ratio will suit ( 100 to 1000 rpm)
I've never needed to run a drill at 4000 rpm with the fastest ratio
and a fobco may even struggle with a 40 mm forstner bit with only a 1/2 hp motor

 

[Fergie 307]

Hmmm its funny i spend all my working days working on motors and VFD's on small to massive machines > 5 million£

I guess i missed out the line once you have chosen a suitable belt ratio then the VFD will suit
i'm not suggesting that you can go from 1mm in hardwood to 75mm with the twist of a dial
but if its for wood the 2nd slowest ratio will suit from 20hz to 100 hz (so 200 rpm to 2000 rpm)
if metal the 1st ratio will suit ( 100 to 1000 rpm)
I've never needed to run a drill at 4000 rpm with the fastest ratio
and a fobco may even struggle with a 40 mm forstner bit with only a 1/2 hp motor

But in your example 20hz at 200 rpm you have massively reduced the torque just when you potentially need it most.
So I agree that a vfd can be useful in fine tuning the speed within a given gear range, but 200 to 2000 is a bit of a stretch if you want to maintain torque, especially when you have a fairly small motor to start with.
And as an aside If looking for a replacement motor I would certainly try and see if I could find one that will fit, but with a bit more power.

 

[Woody Alan]

I've been through this with the motor. You can fit a cheaper import metric but you'll have to bore the pulley or reduce motor shaft. I am going to fit Imperial B56 frame motor so avoid the hassle and keep to standard. I am going 3 phase just because I have an inverter and like the soft start and other options. In quotes is the reply I receieved on enquiry from Newton Tesla regarding the motor.

" Yes, I too would fit an Imperial motor - as we know the shaft diam and the foot fixings will be the same - and in keeping with the machine.

You could go for either really - TEFC or Drip-proof. But as its on a Pillar drill, and the motor is out at the back - I would go for the Drip proof - as the terminal box is on the end, not on the top."

 

[Fergie 307]

Soft start, and braking both handy features with a vfd.
I fitted a modern metric motor to my old lathe. As you say had to bore out the original pulley and cut a new keyway. Not a problem if you have the kit, PITA otherwise.
In my case it was just because the second hand metric motor was really cheap, from a firm that specialised in three phase to single conversions. They used to sell the 3ph motors they had taken off on e bay. My fairly new looking 3hp motor was about £65 so worth doing.

 

[Sideways]

from 20hz to 100 hz (so 200 rpm to 2000 rpm)
if metal the 1st ratio will suit ( 100 to 1000 rpm)

Simplifying and giving a practical example just using a 1:1 ratio through the belt:
You have 4 pole motor, 1400rpm spindle at 50Hz
At 20Hz it will do 40% of speed so 560rpm
At 100Hz it will do 200% of speed so 2800rpm
2800/560 = 5
That's a 5:1 ratio not a 10:1

And it is a very specific setup that most amateur users of VFD's won't know and may not even be able to configure. Overdriving a motor above nominal frequency (ie from 50Hz mains upto 100Hz double the mains frequency) does indeed spin the motor up faster but the torque reduces as the motor speeds up above 50Hz.

So, no. I don't agree that variable speed on the VFD is an adequate substitute for moving the belt.

 

[flh801978]

My example was from the rated speed on the fobco label on the quill
I must remember to clamp my speed controls to 50hz and only use the pulleys in future

 

[AJB Temple]

Honestly you guys are overthinking this. I've had a Fobco Star for years. Original motor. It is perfectly capable of running a 40mm Forstner bit through hard seasoned oak - and will do so like it is butter.

In the real world, especially woodwork, you will hardly every change the belts and hardly ever want high speed rotation. With a pillar drill you don't need soft start or a brake or variable speed.

It's a rock solid bit of kit. Keep it simple and just use the thing.

 

[Fergie 307]

Agree, soft start and braking useful but probably more for a lathe than a drill.
And you are absolutely right, I suspect most people rarely move the belt.
I think it was just about belt change versus variable speed if you do want to change the speed.
Personally I am fortunate to have a few pillar drills, so have them set up according to what I use them for. But if I do need to change speed it only takes a few seconds to move the belt, so hardly onerous.
I much prefer to leave machines largely as they are, so use my lathe with a vfd but no variable speed. It has sixteen speeds as it came from the maker all by moving a couple of levers, quite good enough for me