David's Mini Lathe......

[John Rudd]

I converted a Clarke CL300 tailstock to camlock.....copied the exact same from my Sieg SC3... Worked a treat..

After sorting the motor ( had to buy a new one..) and speed controller, I sold the machine on....

But the camlock is one of the best mods ever for the minilathe...

[Stilldrillin]

John.
 I guess your conversion would be quite robust, compared to the genuine Sieg version.

I wouldn't like to try to drill 6mm, in m/s. The tailstock would be retreating, under load.

[Stilldrillin]

Sorry for the usual delay. Life, yer know..... 

The magic box, of coloured magic parts, came back from John's.

It works very well. The wheels go round, just like they used to do..... 




I was surprised to see, the original lathe is rated at 3,000rpm.

This set up peaks at 3,600. And, the bearings don't like it. They gibe, and the motor cuts out. 

I guess, we now need to lower the overall gearing......

[John Rudd]

What bearings are you running? Tapers? Is the preload set ok, not too tight?

[Stilldrillin]

Yes, tapers. Not set for any machining, yet.
 Just gently nipped, until there is no discernable movement, felt by hand.

The proper set up, is to come after a bit of running in.

[Stilldrillin]

Managed some workshop time, yesterday.

While I was busy, I set the lathe running in Lo gear, 700 rpm.
 Tweaked the bearings, after 10mins, and upped the revs.

Eventually reaching peak revs in Lo, 2,180. (Seems rather high to me)......  

All seemed ok, so I changed to Hi gear.

Ran for a while, eventually reaching 3,000rpm. The supposed peak revs. 
 Wound it up, a bit. Reached 3,600. The digital reading stayed there, but the revs continued to obey the speed control.

The bearings seemed happy. Not getting warm at all. So, I tweaked the speed control a bit more...
 The revs climbed higher! Until the motor cut out, with a, "PUP". 

Apparently, no harm done! (Except to my nerves). It re-started, as usual. 

Grabbing my laser tacho, I decided to see just what were the peak revs? 
It peaked at 5,000rpm!!    .. Before going, "PUP",  again.


That's just a bit too enthusiastic, for my liking....... 


Time to check the motor. Should give 6,000rpm. According to the label.....




Reflector tape, on the pulley......




By ek! We must have the GT model.......




John suggested checking the voltage supplied to the motor. As, this determines the motor speed.

The result wasn't helped by my 35yr old meter reading x 2(+).

500+ volts! I don't think so.......




New meter on order. Further fumblings, in a few days time.

Any comments/ helpful advice gratefully accepted...... 

[Stilldrillin]

The new multi meter arrived, early this afternoon.

After a bit of familiarisation,    I checked the full revs voltage to the motor.

That's, ok......




John suggested, I check the speed pot, R3.

As the other two, are sealed, with gloop. I guess, someone has twiddled with R3......




I set the lathe running, sensible revs. Rotated R3 anticlock. The revs reduced! 

1/4 turn at a time, on R3, while increasing the speed knob setting.

After almost 2 turns, we hit a "stop". Flat out at.......




Guess the "stop/ resistance" was the original position of the pot. I'll leave it alone from now on. Probably. 

Sincerest thanks to Mr. Rudd, for his help and guidance, through fings wot most of us don't understand. 

[Stilldrillin]

Spent ten mins in a perrishin' cold workshop, today.

The lathe produced blue swarf, from a piece of 1" dia unknown steel, just as I hoped it would. 

I now have the rest of the winter/ springtime to bed it in.
 While making a few mods to my original, mongrel mini lathe. 

[Meldonmech]

 
 A very interesting post.
                                              Cheers David

[Stilldrillin]

 A very interesting post.
                                              Cheers David

Thank you, David!

Nothing much of interest will happen, over the next few (cold), months.
 If/ when it does. I'll post pics etc.

Incidentally.
 The next owner, says he would like a Dixon toolpost installing. Before delivery..... 

[DavoDavo]

David looks like theres an issue with the board then...

Would you like me to look at it and effect a repair? 

( I just checked, a new board is £132... From Arc..Ouch, didnt think they were that much...)

Hi John,
Sorry to hijack this thread but I'm hoping you can help me.
I have a Sieg X2 Mini-Mill with an FC350BJ/230V motor controller board that has bitten the dust  (motor speed goes berserk on full throttle - somewhere around twice its rated speed of 6,000 RPM).
The motor is 350Watt 230V, same specs as the lathe I believe.
The original board is no longer available and it seems that the replacement is the XMT-2335.

The XMT-2335 has more terminals than the old board and I haven't been able to see how they are labelled from any pics of it, and I don't have a circuit diagram for the mill either, so I'm wondering how to wire it up, I looked very carefully at the pics that were posted of David's lathe controller but couldn't see how it was wired - you mentioned a small transformer in one of your posts but I think that is a power supply for the lathe speed display.
The terminals on the FC350BJ are:
1 and 2 - DC for Motor,
3 and 4 - AC for 230V Mains input,
5 Not sure what it's for (goes to one of the switches on the panel I think, the board is on my desk right now), and
6 and 7 jumpered together.
And then there are P1, P2 and P3 for the control pot.

  I'd be very grateful if you would let me know what you can about it, you know a lot more about these infernal devices than I do.

Many thanks from an Expat-Pom living in Australia.

Cheers,
Davo.

[John Rudd]

Dave,
Helping is no problem....
I'll dig out the schematic for the XM board, I think the best thing to do is take this off line...my email address should be in my profile or you could pm yours to me....

If the motor is going flat out then chances are the fets are shorted....board can be repaired but I doubt you'll find any one down under...you could send it to me here in the uk....

[Stilldrillin]

By ek!
 It's been a while, since I showed anything about this project. 

All the loose bits have already gone to Scotland.
 And the lathe is slowly being crated, ready to follow.

Must find and show some pics.....

[Stilldrillin]

This lathe refurb, was always intended to be a long term project. As, when, and if....
 Consequently, it is still on schedule. 

Back in February, a new 4" chuck and adaptor, arrived......



I made three balance plugs for the redundant holes in the adaptor plate. Then realised, only one was needed! 

I like to fit 40mm x m6 grubscrews, shortened as necessary, as chuck studs....




Everything fitted together well. But the workpiece insisted on 5thou'+ eccentricity!
 Started to check every locating point.....




All's well here, too......




That's disappointing! The chuck is 5-6 thou eccentric, on all three (six) jaws...... 




Relieved the locating recess, by a few thou per side.
 It's easy enough, while changing chucks, to set true to a mandrel. Before finally nipping the chuck nuts.....




Thanks for looking in! 

[vtsteam]

 

Great project David! Sorry I've been away and missed the start.

 

[Kjelle]

  Welcome back Steve!! Missed you!

Kjelle ( in Sweden!)

[vtsteam]

Hi Kjelle,
I haven't done any metalworking in over a year. But I know I will get back into it at some point soon. I tend to cycle through interests every several years-- taking a break periodically, but never giving them up entirely. I guess dropping in here tosee what's happening is a sign I'm thinking about it again.

[tom osselton]

Nice to see you checking in!

[vtsteam]

Thanks Tom!