KATSU MINI LATHE

Hi i have a katsu mini lathe it was working fine but then i didnt use it for about 3 weeks and when i did it switched on lit up numbers but when i put it in forward or reverse it trips my mains fuse , any one had this happen

Gosh Gary, nearly missed your post. Perhaps because it's your first it was delayed and never got into 'Latest Forum Posts', which is what most of us keep an eye on.

Not familiar with the Katsu badge but it looks like a fairly typical mini-lathe, somewhat cheaper than most examples.

Mini-lathes do sometimes develop problems with the motor or the control board, usually caused by overworking or because swarf has got inside the electronics. You may have been unlucky and got a dud; blowing fuses after a rest isn't a good sign. Might condensation be a problem?

If it's new contact the seller.

If out of warranty what you do next depends on your resources, in particular can you do basic electronic fault finding and use a soldering iron?

Step 1. Unscrew the plastic box holding the controls and move it enough to reveal the electronics. Check carefully for swarf and signs of burning or other damage. Chief suspects are the power MOSFETS, electrolytic capacitors, and the bridge rectifier. In failing these might blow out parts of the copper track on the circuit board. Shorts can be tested with a multimeter, and the offending components replaced & tracks mended with simple soldering. The parts are readily available on the internet. Except it's not simple if you don't have the skills or the tools! Or you might be lucky and fix it by removing some swarf.

Step2. It's possible the motor has failed. Check by disconnecting it from the control board and applying the leads to a 12v car battery. It should turn slowly. If there's a big blue flash and smoke you need a new motor. These are readily available. If nothing at all happens, you probably need a new motor. (They should start with 12V but not always.)

If the board failed, the motor should be OK. If the motor failed, there's a good chance it killed the board as well, especially those MOSFETS.

If mending electronics isn't your thing, you can buy spare control boards and motors and fit them yourself. Carefully note where all the wires go before removing the old board, photographs are good, and plug them back into the new board. Changing the motor and fitting new electronics is fiddly rather than difficult, what makes the job really hard is rushing in, ripping all the connectors out, and then guessing how it might go back together. Don't assume that the old and new wiring is identically colour coded, in fact don't assume anything.

It's also possible to install a different motor and a generic DC motor controller from ebay or such. Easy enough if you know how, but not everybody does!

Unfortunately I no longer own a mini-lathe which makes it difficult to give precise instructions. But plenty of other forum members should be able to suggest detailed help. I hope they'll spot my reply and improve on it.

Dave

Edited By SillyOldDuffer on 02/06/2018 11:05:13

assuming your lathe has a brushed motor

the speed control board could be either like the FC2550 board with 2 FETs controlling the motor current

or the XMT 1135 with 2 thyristors controlling the motor current

once the control board has been identified it will be possible to give you more detailed help for your machine

John

Edited By john swift 1 on 02/06/2018 12:03:23

PS

your machine could be like this Warco wm180 -

http://andysmachines.weebly.com/variable-speed-controls.html

John

Hi Gary,

If you bought off a UK supplier and it's less than a year old, have you asked them for advice.

The Katsu seems to be one of many 'grey and blue' mini lathes that have recently appeared on the market.

They don't appear to be from either of the better known producers (SIEG/Real Bull) and are a bit of an unknown quantity at the moment.

Time will tell if they really do have less reliable electronics or if other mini-lathe spare boards can be easily fitted as a replacement.

Neil

FYI, for those that may not know.....

The Katsu brand is sold by AIMtools, a seller on Ebay....

If want a giggle see this 'review' site - I'm sure these things are put together by review aggregator bots:

www.top5reviewed.com/mini-metal-lathes-2018/

"This benchtop metal lathe offered by Generic "

"There are lots of versions of lathes inside the metalworking industry. A few variants aren't all that obvious, yet others tend to be more niche.  For instance, a centering lathe is a dual head machine in which the work stays fixed and the heads move towards the workpiece and machine a center drill hole into both ends."

Neil

Edited By Neil Wyatt on 02/06/2018 17:09:16

For instance, a centering lathe is a dual head machine in which the work stays fixed and the heads move towards the workpiece and machine a center drill hole into both ends.

The reviewer is not wrong :

**LINK**

Quite how that is relevant to a mini lathe review, though, isn't immediately obvious.

Nigel B

But it isn't a lathe... which is part of why I think that site is assembled by robots or people typing into templates after a swift google...

Edited By Neil Wyatt on 03/06/2018 13:27:25