I Put A 3HP Motor On My Mini Mill

G'day everyone

The control board for my milling machine (Sieg x2.7l) has recently blown. It is not exactly a huge surprise, these DC motor boards are easily the weakest part of these import machines, and it was only a matter of time before this one blew. A replacement one was going to cost roughly $400, and given that the motor is already somewhat underpowered, I didn't feel that that price was worth it.

Now since I have recently replaced the mini lathe I have a spare 3 phase 3 horsepower motor on hand, plus a VFD, and by sheer coincidence the total cost for that was $400.

So I might as well put that on the milling machine and see what happens. Of course its not that straight forward, the motor is oversized and wont fit in the stock housing. So I'll have to make up a bracket. I'll also have to figure out a way to make a replacement 5M pulley to change the pulley ratio. I'll also have to figure out how to connect the VFD to the standard control panel.

Also I find a way to break every tool that I end up using. Just one of those weeks.

Timestamps
0:00 - Introduction and 3HP motor
2:58 - Making The Motor Mounting Bracket
6:23 - Making A Replacement Pulley
11:15 - Wiring the VFD and Making A Replaement Cover
14:00 - Testing Out The New Motor

#machining #millingmachine #minimill

Mini Mill 3HP Motor
Milling Machine 3HP Motor
Milling machine Motor Upgrade
Sieg x2 Motor upgrade
Sieg X2.7l Motor upgrade

[artisanmakes]

Do you ever have one of those weeks where everything you touch breaks? Pretty much sums up my past 2 weeks :)

[Tympan]

Here’s a tip for using holes saws in thick metal: touch the hole saw onto the metal so it scribes the perimeter of your hole. Then remove it and drill 4 small holes (at 90 degrees) around the perimeter right through your material. The outside edge of each hole should be aligned to the outside edge of the perimeter. Then resume cutting with the hole saw. This allows for the chips to be pushed out through the four holes and prevents them building up and causing heat and damage to the saw. Also use cutting fluid. And then go and buy an annular cutter and never use a hole saw on thick material again 😂. Great videos btw.

[Adamant]

Quick tip. If you have aluminum welded to an insert, soak it in lye water. Lye will dissolve the aluminum and won't effect the insert or steel cutter. Works great for files too.

[Crocxr]

Hey mate, a tip when drilling through anything thick with hole saw, but works especially well on steel. Drill a small hole in the path of the circle you're cutting. When drilling through thicker material, as soon as the cut is deep enough to cover the hole saw teeth, the chips have nowhere to go. The teeth will get clogged and you just end up rubbing instead of cutting.If you drill a hole first, the chips will be able to exit the cut through the bottom, and you wont have to pull the hole saw out to clear the chips every few seconds. Faster cuts, and less rubbing keeps your bits sharper for longer.

[meckarelis]

I just got my first lathe and a couple of days before that got accepted to a machine based highschool. I have had a lot of interest with machines since i was really small. The interest was then growing after i found "this old tony" then i gound your channel and now i have applied for that school and managed to get my dad to buy me a little lathe. Thanks

[malteser]

little tip for cleaning cutting tools with aluminium welded to them: lay them in a solution of Lye (sodium hydroxide) for some time, the NaOH dissolves the aluminum right away without hurting the cutting tool.

And please give this VFD some air to breathe. It might not be a lot of heat to feel, but it accumulates. And while it might not decrease it's power, it will surely affect the VFDs lifetime.

[FlyingDismount]

Yes inductive losses go up with frequency, but if you are only doubling line frequency, there is no issue at all: the VFD waveforms are much higher frequency anyways, and your motor is fan cooled and finned, so I would have no worries going even higher than 2x if necessary.. Just watch the torque requirements and take shallower cuts to keep the currents low, as it's I^2X, so even if the reactive losses become much higher, they are still small compared to the current squared.

[billsmith]

Really looking forward to your rigidity improvements. I think you'd love an inexpensive plasma cutter. I've had mine for 3 or 4 years and it's still just fine. I hope I didn't just jinx myself.

[ThePunischer]

Field weakening with the VFD is no problem. However the torque will decrease and the efficiency will suffer a bit. But when you set up the current and power limit correctly in the VFD it is absolutely fine and standard practice for induction motors.

[rodbutler]

Two points of contact for rigidity. The base to the bench (of course) and the motor to the wall. It has made a significant improvement to my converted drill press/mill. Can’t see why it wouldn’t work similarly in your situation. The centrifugal forces in that bigger motor is getting everything else to rock-n-roll. I will be very interested to see what you come up with. Luv y’ work.

[nathaniellangston]

This video has it all in it! Turning, casting, welding, milling! Great video!

[GeoffTV]

Great video, thank you. I have had a Sieg x3 mini mill for many years now. It has the exact same 1hp brushed motor and controller as yours. I got about 7 years of use before the controller died and like you was horrified at the cost of a replacement board. I did keep my motor and just replaced the controller with a £20 one from eBay. It has worked flawlessly but now seeing this, I wished I had replaced the motor too.

[Dave.Wilson]

A modification that I definitely need to do to my mini mill, the lathe has a 3hp 3 phase motor on it, and it is far more usable than previous. I'll be taking inspiration from you, thanks for sharing. Cheers from the UK.

[jamesstuartjamieson]

Not a fitter engineer but thoroughly enjoy watching the videos and appreciate the humour

[scroungasworkshop]

I can recommend Suttons “Venom” cutting fluid. I was sceptical but it really works to make drilling and tapping easier and you can buy it at Bunnies. I can also recommend the Metabo WEPBA 19-125 5” / 125mm angle grinder. They’re not cheap at around $499 but, buy once, cry once and they have a lot of safety features. With a rated 1900 watts they also have the power of a much bigger grinder. That’s 700 watts more than your new Ozito and boy do you notice it. With so much extra power the blade doesn’t slow down so cutting and grinding is much faster. The difference is incredible. I bought two of them after a serious accident with a Makita. I hope this helps, Cheers Stuart. 🇦🇺

[tedayer]

Great job. It should make the machine easier to use. And congratulations on the new tool acquisitions.

[gonzos-twin]

Ive always thrown a thermal camera on a board thats pooped the bed. 90% of the time I find the issue, but you've done right with upgrading that nice machine

[louiel]

I ended up putting a 600 watt sewing machine AC servo motor and control on the mini lathe after the board died, $120 fix, stupid board was $250. Much more power although now the lack of rigidity is really showing especially when boring. Great video thanks.

[Dev_R]

This video was the definition of buy once cry once. Sorry about your whole shop ending up busted, good job pulling through!

[anothermidlifecrisis]

Just a tip from a 12 year Millwright, when zip cutting don't press hard. Just keep enough pressure to keep the disc from chattering and sweep the entire cut back and forth steady for the deep cuts. Your discs will last ages longer. Gentle as you can be, let the disc and tool do all the work.