Help needed. My mill broke yesterday

[Rolf]

I have a Sieg Sx3 super mill. It's made in China and identical to the Grizzly model G0619 deluxe small mill/drill sold in the USA.


I took a too deep a cut when milling mainspring blanks. The mill stalled and the emergency stop button engaged and stopped the mill.
I reset the stop button and tried to start the mill. I got a high pitch electrical whine and no power to the motor. The whine comes from the front of the mill housing.
When I turn on the mill the RPM readout lights up, displays no numbers or messages. So, I asume there is power to the readout.  Can I presume that the Digital SPD. Display unit is okay, or could it be broken and cause the whine?



I took off the front mill housing. There are only two parts here.
1. control panel pc board N/C
2. emergenency stop switch

Could any of these parts cause the high-pitched whine?


The firm in Norway who sold these mills is liquidated, so I'm hoping someone on the ALR has suggestions.

Best regards
Rolf

[44-henry]

Go to www.littlemachineshop.com. They have all the parts you will need and can help you figure out what happened and how to fix it.

[Bob Roller]

Machines that are smarter than I am are scary but that includes hand cranked drills. My old Clausing 8520 represents the best of the technology of he 1920's and so does my thinking.If you get it going again,see if you can get some end mils with more than 4 flutes to help reduce the chance of a grab and stall on a small machine like that.I changed to them about 6 years ago,solid carbide from Maritool or Kodiak.You'll never go back to 4 flute high speed again.
Bob Roller

[Gaeckle]

Start with the basics: any electrical smells indicating a burned motor? Can you turn the motor and quill by hand? Have you looked at the electrical schematic for any sort of overload that has tripped, any small fuses that may have blown? Is the manufacturer still in business and can you call a technician that can point you in the right direction?

[Bob Roller]

The manufacturer probably speaks Mandarin but probably has an English speaking tech that might help.The metal cutting bandsaws seen here yesterday re a marvel of low cost,high end tools.I have a friend who teaches electronics and motors and switches and is skeptical of the motors but so far so good for me but my fairly low usage can't really be figured in longevity.
Bob Roller

[JTR]

Are you sure the machine broken hasn't broke a shear pin, and you have no drive to the chuck? If so, the high pitched whine could be the disconnected motor running with no load?

With nothing at all turning, the high pitched whine could be the solid state speed controller gone poof.

[P.W.Berkuta]

Try this web site <https://www.youtube.com/@Blondihacks>. She has had a issue with her precision matthews mill which is also a Chinese made mill. She fried her fuse & control board. She is one smart machinist and uses precision matthews lathes and mills for her projects - I think you will learn a lot from her - good luck.

[TDM]

Agree with JTR.

[Bob Roller]

Are you sure the machine broken hasn't broke a shear pin, and you have no drive to the chuck? If so, the high pitched whine could be the disconnected motor running with no load?

With nothing at all turning, the high pitched whine could be the solid state speed controller gone poof.

That IS a possibility.There may be a built in safety that prevents real damage if a mill grabs. I know that can't be a high torque motor like my old Clausing that can easily shatter 1/2 inch end mill.I saw one of these little mills advertised with R8 collets. Really? That is a big American size like an Index or Bridgeport.
Bob Roller

[44-henry]

Again, contact Little Machine Shop. They deal extensively with these machines, including your mill, stock replacement parts, and also have the technical expertise to diagnose your problems without a bunch of guesswork.

I have owned both lathes and mills made by Sieg and I also have several of them in my University lab. They are fully capable within their size limitations.

[Rolf]

Thank you for all your suggestions. Quill turns freely, no burn smells, no blown fuses.
But I think I have found the answer. There is a British store that sells these mills and stocks spare parts(Arctrade.co.uk).
According to them the Sieg 3x mill has two weak spots.
1.The old emergency stop button
2. A relay on the main control circuit board.

If the stop button breaks/fails, the relay on the main circuit board is often fried.  They have even put together an upgrade kit to solve the problem.
Here's a link to the kit https://www.arceurotrade.co.uk/Catalogue/Machine-Spares/SX3-Mill-Spares/SX3-217-Main-Control-Board

I'm going try and change the stop button first. If that does not work, I'll buy the upgrade kit.

Best regards
Rolf

[Gaeckle]

Awesome! Good luck 👍

[Rolf]

I got my mill fixed. Had to buy the upgrade kit.
 https://www.arceurotrade.co.uk/Catalogue/Machine-Spares/SX3-Mill-Spares/SX3-217-Main-Control-Board
Changing out the parts was surprisingly easy!! All the wires were numbered. All I had to do was to put the right in the right socket.

Started up again on the mainsprings for the percussion locks.

Best regards
Rolf 

[Adrie luke]

Surch

Sieg Sx3 super mill. pcb   Ali Express on Google

Look Pictures

Adrie.

[Adrie luke]

http://esorensen.com/lcd-control-board-for-sx3-mill/

Maybe better

[Rolf]

Thank you Adri for the websites. I've saved them on my browser. It's good to have options.

Best regards
Rolf

[Bob Roller]

Good! The little mill is running again.I was looking at pictures of some fine English 3 and 4 screw locks and ONE caught my eye and it was a 4 screw that had the sear spring captured by the 4th screw.I have a scaled down version of the full sized match rifle 4 screw lock about 2/3rds done and I think I will try this idea.I hope you have all success in the spring making.Springs are a seperate skill set from the mechanism of any lock.
Bob Roller