Add spindle to conventional Z

I’m considering adding a 800w or 1.5kw 65mm watercooled spindle to my conventional Z axis Shapeoko 3XL.

Has anyone experience with this. I’m concerned about having to add/reinforce springs to handle the additional weight.

Have a search of the old posts on the forum here.

There’s been quite a bit of discussion about this, including adding extra return springs etc.

My opinion is, don’t spend your money on a spindle without at least going to the Z+

The belt driven Z has so much deflection that even if you do get the spindle mounted and operating properly you’ll get no benefit (other than reduced noise if you go water cooled).


I upgraded to the HDZ in March. It was a great upgrade. I have no experience with the z plus but the HDZ makes my xxl so much better.

The extra weight of a spindle even with different springs might work but MIGHT work. You could try it but if it doesn’t you could then buy the hdz/z-plus.

The original z carriage works ok but with loss of zero is ever present.

I ran a 1.5kw 65mm spindle in my stock Z-axis (the belt driven one) for a long time with no issues.

A spindle is a great upgrade, but the only reason I’d do that one before upgrading the Z-axis is if you’re desperate for noise reduction.

An HDZ/Z-plus/CNC4Newbies Z-axis upgrade is the best money spent on the stock shapeoko 3 in my opinon

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Did you have to change/upgrade springs?

Did you upgrade/change springs?

Hi Bill,

I added a 2.2kw spindle (just to the stock Z-axis) and was a bit concerned about the extra weight so I made a bracket to hold stronger / longer springs (longer to get a bit more of a constant-ish) force.

Here is a link to some pics in a post I did at the time:

I don’t know what the weight of a 1.5kw unit is - but if it’s not substantially more than your stock standard Dewalt/Makita unit I probably wouldn’t worry about it too much.

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Nope no change to springs or any part of the machine. The only thing that changed was due to the extra weight of the spindle, when you cut power to the machine the Z axis would hold its position, whereas with the lighter Makita router that I had prior, it would spring up when the power was cut.

If you want it to always raise on power loss (which isn’t the worst idea) then heavier springs may be required. I wasn’t that fussed and never had an issue

I tried to use a 1.5kw spindle with a belt drive z. I could not find springs that would support the weight and allow plunging to the waste board without skipping z steps. Was very frustrating.

I ended up returning that spindle after the vfd failed. Went back to a stock spring and a carbide router until I was able to get an hdz. Now have a 2.2kw spindle and an hdz and am very happy.

Imo there is no point in going to a 1.5kw spindle. It weighs about 1 lbs less than a 2.2kw. The 2.2 can take half inch bits.

An 800 watt should be ok with a stock z and maybe some different springs. It is significantly smaller and lighter.

I have never come close to drawing half the rated amperage of my 2.2kw spindle. And all my
Spindles were water cooled.

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I won’t argue with your experience, but that’s not what I’ve seen. The 1.5kw with the stock Z-axis worked fine, no missed steps

Was your 1.5kw a 65mm or 80mm spindle? Mine is 65mm and only weighs a bit more than the Makita router.

As I said earlier I think the z axis upgrade is better to do first, then the spindle.

I’ve never run out of power with my 1.5kw, The only reason I’d go to 2.2 is the bigger collets to allow for larger tooling. Even then it’s hard for me to justify the cost cause I don’t really have issues with 1/4" tooling.

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One thing I’m curious about — 8mm (5/16") tooling is far more rigid than 6.35 (1/4") — have folks found it to perform well enough to justify the expense of a collet? I have the collet, but thus far my only 5/16" tooling has been specialty usage — haven’t found an affordable square endmill at a reasonable price.

Is anyone else experimenting w/ this size tooling?

I wonder if has anyone tried a counterweight for heavier spindles?

The original belt Z axis is good but Cardide3d has improved with the z-plus and hdz. Any spindle you put on a belt Z is limited by the loss of zero because of the nature of the belt Z not the spindle choice. The heavier the spindle multiplies the chance of belt slippage on a belt Z. C3D is only shipping the Z-Plus on new machines because of the improvement and the competitive advantage in the market place.

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Well, a counterweight has been suggested at least — the problem is it increases the mass of the carriage/gantry.

I’ve just started on this 10mm dia 3 flute Aluminium cutter, it’s able to do deeper cuts as the same WoC than the 6mm single flutes. It says “brrrrrrrrrp” and lots of material flies off quite quickly.

The finish is poor compared to the single flutes at 22kRPM. I’m running this at the recommended 10kRPM so far. I think the finish sucks because I’m not pushing it fast enough, but I hit machine vibration before I get up to the recommended feed rate. More experimentation needed.


Hi Will,

Yes having the flexibility of an ER20 collet is so worth it. I have collets up to 16mm - I think 13mm is the traditional ER20 max - but I’ve got 14, 15 and 16mm ones - I like big bits! :wink:

Back on topic - I use a fair amount of 8mm tooling, and I really love 4mm (can take quite a bit more than 1/8", but doesn’t require the space of a 6mm or 1/4".

I’m in Australia, and sourcing metric bits is just so much easier for me - so being able to get a collet to hold anything makes it a no brainer in my case.


It was an 80 mm. I could not find any 4 bearing water cooled spindles smaller than 80mm.


But 16 mm in an ER20 - that sounds very interesting. Where did you find that collet? Is it difficult to remove from the collet nut? (I’ve got a 12 mm for an ER16; useful, but no fun to swap out.)

I sourced it from China some time ago - I had a need to hold a 16mm shank, wondered if it was possible - did some searching and found one.

As it turns out - the ER20 nuts have a 16.00mm opening on the front, and I had to open that up ever so slightly to get the bit in easily. Perhaps it’s all a tad dodgy - but as Luke says - hold my beer and watch this…

As far as fitment - it’s a bit more fiddly given it is smaller than your standard ER20. But possible. I only use it on special occasions :wink:

I did a quick search on Aliexpress (I didn’t get mine there) and found this link:

You can see the 16mm is the short squat one - there isn’t much meat left as it only just works out. To roughly quote John Candy’s character in Armed and Dangerous - “It’s only legal in two states, and this isn’t one of them…”


Datron 8mm SF tooling runs awesome and they have stepped endmills with 8mm shank.

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