Buying a used Mikini

**Tinmuk** · 01-02-2014, 10:07 PM

Hi,
I am picking up a used Mikini mill this weekend. I got to see it under power and the jog functions worked as well as the spindle. However the computer wouldn't start, so I couldn't see it run a program.

It also has a rotary table, but no drive unit for the rotary axis, so I called MikiniMech to see about buying a driver. There ws no answer and their website is down.

Are they out of business? If so can I just wire in a Gecko drive for the rotary axis? Does anyone have a wiring diagram and operators manual I could get a copy of?

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**SWATH** · 01-03-2014, 12:00 AM

It appears that they are out of business. No doubt from potential buyers searching the web first and probably stumbling on this forum. We have been on our own here for a while now. The spindle issues probably killed them. Fortunately many of us have fixed the associated problems plaguing this machine so there is a ton of info here on this forum about them. Also it appears that a company called Skyfire has either acquired the company or the designs and is making an almost identical copy of the Mikini called the SVM-2. Their website shows products that look directly compatible at least physically (like spindles, and even an ATC).

I'm going to go out on a limb and predict you will be sick of that spindle in no time, in which case you can read the thread about the VFD spindle motor replacement. Lots of good info there.

Here is a block diagram from the manual. It is the most detailed thing Mikini has provided in there.

Post#6
http://www.cnczone.com/forums/mikini...ont_ask-2.html

Good luck! I hope we can help with your problems.

**mcphill** · 01-03-2014, 09:55 AM

Sorry for your loss. I hope you got a KILLER deal.

If I got what you have, I would start by gut ripping the entire electronics package/controls and spindle motor. Do a retrofit with decent (and documented) components.

**Tinmuk** · 01-03-2014, 09:01 PM

Sounds like you two have had some issues with your machines... I know this will be a bit of a project, but I don't think it will be too bad. I will not mind if I have to replace all the electronics. I have a little bit of experience with stepper drivers and I am not afraid of getting dirty.

BTW, I think $2k for the whole thing is a killer deal, even if I have to rewire the entire machine. What do you reccomend to replace the spindle motor and drive with?

I will pick it up tomorrow morning and it will probably take a week to get it into my garage. I have a mill and a gear hobber in the way and will have to move things around ro make space. Once it is in place I can start sorting out the issues and see if you guys can help with any problems... Soundslike you have the expertise to make these work!

**mcphill** · 01-03-2014, 09:59 PM

For $2k you did well. The problem with this machine is the stock spindle drive/controller. It will not run constant speed and it has very weak low speed torque. Replacing the spindle motor with a 1.5 hp AC drive solves those ills. I am still trying to find a BLDC driver to replace the Mikini part so that I can keep the "better" motor technology ("better" in quotes as I don't see any evidence that it is better as yet, but theoretically it is a lighter package with more torque).

I machine wood, foam, and aluminum. At the higher spindle speed that these materials need, it has not caused too much of an issue for me yet, but it does limit me to 3/8" tools (1/2" is too large as I would need to run too slowly and bogs and breaks bits). Also I can't effectively machine steel due to the same issue - but again I haven't wanted to machine steel yet, so that is fine for me so far.

Mechanically the machine is quite sound, and I LOVE the enclosure. It is just hampered by the crappy spindle controls, and relatively "shoddy" wiring all around, and absolutely NO documentation of the system components (no manuals for any of the board level components) - so fixing things is a real shot in the dark.

**SWATH** · 01-03-2014, 10:16 PM

Yeah $2k is great! You did very well. Now gut that think. Mike is right the main problem is the spindle driver and possibly the motor. I want to hear more about the drop in replacement drive you've been sourcing Mike. That would be great then we could do some direct cutting comparisons. BTW I fit a 2hp 4 pole ac motor on. That is as big as I could fit. Going beyond that probably exceeds the rigidity of the machine as evidenced by Allen's cutting videos. I haven't cut much since getting my new motor running but it definitely does sound and feel completely unphased by what little curing I've done unlike the old motor.

Sent from my SCH-I545 using Tapatalk

**Tinmuk** · 01-04-2014, 02:06 AM

It sounds like the basic machine is as good as I thought it was, but the spindle is the weak point. I will look into upgrading it since I plan on making small parts from 303 CRES. I gues the driver itself is the problem? not necesarily the motor?

What does the motor data plate say?

Also cam I use a Gecko drive for the 4th axis?

**slowtwitch** · 01-04-2014, 06:49 AM

Originally Posted by Tinmuk

What does the motor data plate say?

Also cam I use a Gecko drive for the 4th axis?

There is no data plate on the motor. The specs say it's a 2.2KW motor ...which i think is very suspect

I'll repeat what has already been said and say you got a fantastic deal. Good luck with your conversion

**mcphill** · 01-04-2014, 10:35 AM

I would recommend you put in a SmoothStepper (my machine ran MUCH better with it in place). You have the freedom to use whatever drives you want for extra axes, as it is all controlled by Mach. Did you get the computer with the machine? You will need the XML file for the Mikini in Mach3.

**Tinmuk** · 01-04-2014, 04:31 PM

Well I made it home ok with the Mikini. 40 miles each way in L.A. traffic! I had them load it it with facing the back of my trailer so i could work on it while I make room in my garage.

It has a quick change on the spindle,with two tool holders. I need to find out what kind of holders they are. It also came with a manual rotary table as well as the electronic one. It has a Kurt 6" vise and a import 4" vise on a swivel and a toolmakers sine vise.

It does have the integrated PC and touchscreen monitor and pendant, but I was not able to get the computer to turn on. Is it controlled by the front panel?

The sheet metal and paint will need some work as well as some of the limit switch wiring. It is also missing one of the Z-axis struts. Can I get a replacement from Autozone?

I will post some pics later. I am excited to get this running. BTW, I used to run a Tormach series three, so I a little familiar with the quirks of Mach3.

I will look into the smoothstepper, a friend of mine is using to control the 3d printer we are designing.

Thanks

**mcphill** · 01-04-2014, 09:15 PM

Where are you near LA? I used to live in Moorpark...

**LeeWay** · 01-05-2014, 03:48 AM

I live in LA as well. No, not Louisiana. Lower Alabama.

**Tinmuk** · 01-05-2014, 01:24 PM

I live in Santa Clarita. Are there any Mikini owners near me so could see what it should look like? Apparently the previous owner did some wiring mods, especially around the main power supply board. Can someone send me a pic of the board and breaker setup?

I also found a loose yellow wire on one of the connectors under the front display panel. It is broken right at the connector so I will probably have to redo the whole thing. I dont know what it is for, but I was able to jog the macine and turn on the spindle. Maybe it is for the coolant?

I did get the PC to start and Mach3 runs. I joust want to sort out the power before I connect it

**TiagoSantos** · 03-06-2014, 12:10 PM

I'm a couple months late to this thread, but wow that's a deal. If you get tired of it, I'll drive down from Vancouver BC and pick it up from you for 2k

There was a mention earlier about Skyfire having bought the Mikini designs.. I don't think that's quite the way it went! Skyfire is run by a Chinese fellow who works for a machine tool manufacturer in China. He is a very smart guy and very helpful as well! Anyway, the company he works/worked for made the machines for Mikini - at least the mechanical stuff. A little over a year ago, I sent him a few emails asking for some parts I needed for a conversion I was working on. He sent me pictures of the things I needed and I recognized the Mikini parts in the photos.

I'm sorry to see that many of you guys got stuffed.. I really believe the Mikini hardware was a fantastic base to start with and I wish Phil had changed his mind about the spindle a bit earlier. I exchanged some emails with him a while ago and I really think he had the best of intentions. But making and selling these machines is a risky proposition and once you make a wrong move, it's very hard to recover from it.

**SWATH** · 03-06-2014, 03:13 PM

It wasn't so much that the spindle sucked but more that there was little to no effort to rectify it. Any new company or design is going to have some birthing problems but if you don't admit fault and fix them promptly instead of deflecting blame and being accusatory to the customer, you are going to have a bad time.

**TiagoSantos** · 03-06-2014, 05:15 PM

I might have worded it badly, but I agree. What I also meant to say is that unfortunately for a relatively small business like Mikini, once he made the mistake, it would have been very hard to rectify. I imagine that his costs to stay in business were fairly high - if he admitted that the spindle was a bad choice and volunteered to replace the spindles or drives on every machine, that probably would have consumed whatever little profit he had.. In hindsight, it could have been considered an investment into building better relationships with his customers and getting a good reputation, increasing sales, etc.

Anyway - from the outside looking in, I'm just sad things turned out like that. He seemed like a nice enough guy to me, the machines had great potential and for the whole thing to be ruined by such a minor thing (given how easily it could have been prevented/fixed)..

My offer extends to other folks! I'll buy your Mikini for 2k!

**mcphill** · 03-06-2014, 05:41 PM

I'd buy another for...... $2.5K!!! (and that's AMERICAN money!) ; )

Phil was his own biggest enemy... I offered help MANY times to write a manual, work on the website, whatever. He could not take advice or criticism, or admit when he was wrong. Wonder what he's doing now...

I have a spindle controller on the way from SkyFire. Hoping it will be plug-and-play and turn the machine in to what it should have been from the start.

**joeybagadonuts** · 03-06-2014, 08:31 PM

Tinmuk,

Please consider my offer of $3,500.00 plus a dozen sweet rolls a week for a year.
That's right 600 free doughnuts, you cant beat that deal!

JoeyB

**Tinmuk** · 12-04-2022, 10:11 PM

It's been awhile now since I bought the Mikini. Its been a great machine and I've made a ton of parts on it. Never had any of the spindle problems that others have had.

I did rip out the original electronics and replaced with a Centroid Acorn and Gecko drives. just so I had something newer and supported. Plus I like the Centroid software so much more than Mach 3. Still have the original spindle motor though.

I'm using Tormach TTS and its quicker than using the R8, but it does pull out under load occasionally. So I've been reading up on the BT30 conversion. I may do that someday. Maybe when I get the ATC from Skyfire

Anyway, the last job I ran was for a few hundred parts, so I left the mill on for a week so I didn't risk losing home position (it would sometimes jump a few thou on power up/down)

On the last day of running the Z axis started glitching out. I was able to finish the job on my Rockwell mill. But then I started troubleshooting and it turns out the motor failed. Well, mine is an early model without the opening under the motor so I have been working on cutting out the casting under the motor.

While doing this I found another Mikini for sale about 20 miles away from me. This one is in better shape than mine and has already been converted electrically with parts from CNC4PC and the VFD/AC motor setup. He was asking $7k but I talked him down to $2k because of ---you guessed it, bad Z motor.

At least I know how to fix the motor issue now

every thing else works well, but being the way I am I'm going to replace the electronics with an Acorn and sell all the CNC4PC and Mach 3 stuff.

Eventually I will covert to DMM servos like I did with my Hardinge lathe. Gotta love those DMM servos, they are awesome.

It'll be nice having two identical machines. Just thought I would update you guys on my Mikini journey

Tinmuk

**mcphill** · 01-10-2023, 03:17 PM

Congrats! I am absolutely SHOCKED you have had no spindle issues! You are using the Mikini motor and controller?

I am just now getting around to my upgrade again after a 3 year hiatus. Haven't run the machine at all in that time. I had gutted it to do the conversion and got lost in the middle, and just let it sit. Now I am moving forward with an Arduino solution so I can keep the Mikini panel for manual work, and continue using Mach3 for CNC. I have a guy at work that should be able to assist. Here's the setup plans as of now:

Buying a used Mikini-schematic-jpg

I bought a Marathon BlackMAX 2 hp motor years ago. Seems I lost the VFD, so need a new one. Planning to use Automation Direct GS21-23P0 and run as a Vectorless drive. Ordered the PWM to 0-5/10 V converters from Amazon. The Arduino work should be relatively easy (for someone that knows how to use them). I don't have any open questions at the moment other than specifics on parameters on the VFD with Automation Direct should be able to handle, hopefully the plan goes smoothly this time!handle, hopefully the plan goes smoothly this time!