Support needed for 1.5kW spindle

**Morpheus75** · 02-12-2021, 07:57 AM

I wish I had joined this site prior to starting my build! I’m wanting to use a 1.5kW spindle, but my X and Z axis are 12mm blocks and rails. 4 bearings on each Axis. I didn’t realize how heavy the spindle was (around 10 lbs with mount), and I’m apprehensive about using it. Should I scrap the 1.5kW and just use a 500W or .8KW spindle? I’m using Nema 23 to drive. Ballscrew/ extruded aluminum frame. It’s basically the Indymill CNC. Not my own design. The X axis is 665mm span between supports. I’m concerned about the X bearings holding up and also the lead screw used for the Z drive. I really appreciate any advice. I can always hold this spindle back and use when I decide I want bigger and better, but it would be nice to use the VFD and spindle since already bought. Thanks!!

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**jckstrthmghty** · 02-12-2021, 01:42 PM

My understanding, 12mm profiled rails should be able to handle 900+ lbs of dynamic load.

**mactec54** · 02-12-2021, 02:13 PM

Originally Posted by Morpheus75

I wish I had joined this site prior to starting my build! I’m wanting to use a 1.5kW spindle, but my X and Z axis are 12mm blocks and rails. 4 bearings on each Axis. I didn’t realize how heavy the spindle was (around 10 lbs with mount), and I’m apprehensive about using it. Should I scrap the 1.5kW and just use a 500W or .8KW spindle? I’m using Nema 23 to drive. Ballscrew/ extruded aluminum frame. It’s basically the Indymill CNC. Not my own design. The X axis is 665mm span between supports. I’m concerned about the X bearings holding up and also the lead screw used for the Z drive. I really appreciate any advice. I can always hold this spindle back and use when I decide I want bigger and better, but it would be nice to use the VFD and spindle since already bought. Thanks!!

Depends what you expect to cut 500w is not going to do much compared to a 1.5Kw if you have used the steel plates that they have used for those IndyMill builds you should be ok with a 800v to 1.5Kw spindle

**Morpheus75** · 02-12-2021, 07:55 PM

Originally Posted by mactec54

Depends what you expect to cut 500w is not going to do much compared to a 1.5Kw if you have used the steel plates that they have used for those IndyMill builds you should be ok with a 800v to 1.5Kw spindle

I am using those plates. I am also going to reinforce the back side so that both gantry ext alum pieces are bolted together. I will be using aluminum as reinforcement to keep it light. I appreciate the advice from both replies. I will be cutting only wood with this as of now. I may use a dial indicator and see how much it flexes with static load before making the decision to go with the 1.5kW. Thanks again.

**mactec54** · 02-13-2021, 11:31 AM

Originally Posted by Morpheus75

I am using those plates. I am also going to reinforce the back side so that both gantry ext alum pieces are bolted together. I will be using aluminum as reinforcement to keep it light. I appreciate the advice from both replies. I will be cutting only wood with this as of now. I may use a dial indicator and see how much it flexes with static load before making the decision to go with the 1.5kW. Thanks again.

If you plate the back side of the gantry beam then it should not flex very much for a light machine like this, minimum of 6mm plate or thicker would be better, it will be the cutting forces not the weight of the spindle that will cause most of the flex how big is the Beam on that machine, you may want to use a aluminum channel so it will stiffen the Beam in both directions extrusions flex quite a lot without a good support structurer

**Morpheus75** · 02-14-2021, 12:53 PM

There is only 2 20x40 extruded pieces that make up the beam supported on each end by the steel plates. I will add to the back side as it’s the only place. I’m still trying to figure out exactly what to use for this. I am going with an 800 watt (1 hp) spindle to start with. I can set parameters on the 1.5kw vfd and only be out the money I spent on the 1.5kw spindle. I could always upgrade to it, but I just feel like the 5.5 lb. spindle is a better place to start. Again....that’s just an uneducated, inexperienced decision, so I may be wrong. Thanks for the help!

**mactec54** · 02-15-2021, 10:26 AM

Originally Posted by Morpheus75

There is only 2 20x40 extruded pieces that make up the beam supported on each end by the steel plates. I will add to the back side as it’s the only place. I’m still trying to figure out exactly what to use for this. I am going with an 800 watt (1 hp) spindle to start with. I can set parameters on the 1.5kw vfd and only be out the money I spent on the 1.5kw spindle. I could always upgrade to it, but I just feel like the 5.5 lb. spindle is a better place to start. Again....that’s just an uneducated, inexperienced decision, so I may be wrong. Thanks for the help!

That is a wimpy beam look for a Aluminum channel then you will get support in both directions which you need, 800w spindles work well for light cutting and if you are using 120v single phase