Alternative milling spindles for the Nomad

I think you’re a bit out of date, look carefully at the title of the video he posted earlier :slight_smile:

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TBD - @Vince.Fab’s testing is probably currently limited by his power supply and/or machine rigidity…

Well, there you go, I stand corrected.

So I heard back from Jäger and unfortunately their spindles are on the higher end of the price range:

Unfortunately though, I measured the Nomad spindle to be 31.75mm, so it looks like Carbide3D decided to use Imperial units for this part for some reason and it’s not going to be possible to find a drop-in replacement.

Since it’s going to be a requirement to replace the Z-axis anyway, I think it’s fine to look at the larger spindles.

But @Vince.Fab on the topic of larger spindles, does my theory about light cuts with large spindles hold? If you take a light cut with say the Makita spindle or whatever your 1.5kW spindle is, is it quieter than taking a similar cut with the stock Nomad spindle?

Alternatively, can you take heavier cuts at the same volume?

High end/performance stuff often does costs more, but can be worth it if you can afford it.

Not likely - smaller chiploads - (“lighter cuts”) should though. But @Vince.Fab should know.

There’s not much you can do with the stock ones but I have seen a conversion to the all brass sprung lead nuts. I contacted a few companies about high performance replacements but it was hard to get a call/message back.

As far as converting a Nomad 3 lead nuts, well, first you would have to get them. I have been told they are not a direct fit but imo, when looking at the carriage photos, I dont see a lot of change in that area. At that point, might as well convert to 1204 ballscrews.

So Ive thought about this question for a few days. The main thing is, there’s no point being limited by spindle power. Anything watercooled is going to be much quieter than a motor + spindle drive. More power means you have the option to run less rpm but use more tq which can lead to less noise. On the other hand, one of my favorite setups was a 60krpm spindle, light radial all day was almost soothing.

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So far Carbide 3D has said we won’t be able to retrofit and I don’t think I can be bothered to wait for them. I think I’d prefer to just swap out the screws myself. They’re not overly expensive from what I can see.

My theory here was more that a powerful spindle is made for taking more powerful cuts, so will be more rigid and vibrate less while taking smaller cuts, leading to less noise.

Do you think there’s any merit in that?

That’s another good point. The machine is pretty quiet when taking really shallow cuts, so if I take cuts at a similar depth, but more of them to increase MRR, the sound should stay a similar intensity even with the heightened MRR, right?

@Moded1952 the rumors of demise are greatly exaggerated! Between recent arrival of baby #2, actual work and after hours work, I’ve been pretty swamped lately. I’m trying to complete a project on the Nomad at the moment (training wheel adapters for my toddlers bike) but after that I’ll be able to make the last few parts for my angular contact spindles; ran into some heat generation problem with the seals so have redesigned it to have removable non-contact labyrinth seals.

My 2 cents on the topic; motor power upgrade on stock spindle isn’t worth doing. I think the upgrade to angular contact bearing spindle has been the biggest bang for buck improvement to the machine so far. More spindle power than 125W could be cool but the majority of my cycle time is fixturing related and I have almost never ran the same thing twice so reducing cutting cycle time via more power (for me at least) isn’t worth the investment of time/money. That said, definitely keep doing what you’re doing @Vince.Fab, I love following along!

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Skip 'em. Go with the balance bike. Couldn’t believe how easy it was to go to pedals after they got comfortable. Two kids went from not much experience to pedaling a two wheeler this summer… The little one was a bonus, but both were a bit of a surprise. One summer goal was achieved with very few tears, just a little blood, and a lot of wind sprints and a couple of diving saves to minimize the blood and tears.
Sorry … Carry on with your discussion about Nomad Mods.

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Ha, I suspect all the above is true, however, I just found the thing that totally justifies the Nomad to my wife so I definitely need to make these things now! :rofl:

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Glad to hear it!

Do you have any clue how much power your spindle should be able to deal with? If I go and throw a powerful BLDC motor at it, will it handle it?

How fast can your (custom made?) spindle go?

FYI - Bosch uses a NMB 608SSD21 Deep Grove Ball Bearing on the far end of the shafts in their 1617EVS “2 1/4 HP” routers (25kRPM max speed) - likely to provide adequate axial and radial load capability without the expense of high speed angular contact bearings. The cutting end of the shaft (little axial load) has a larger MOS 6004-2RS (standard?) ball bearing.

Since I was screwing with the stock spindle today, I had a look at the bearings. They’re EZO 608 RS bearings.

I found specs:

  • US site: grease-lubricated: 33kRPM but “Max. speeds for the contact rubber seal(s) types will be around 50-60 % of above values.”, so 16.5kRPM-19.8kRPM.
  • Japan site: 18kRPM

So I think there’s not a lot of room for improvement, it’s probably better to replace the whole spindle (and therefore a good chunk of the Z-carriage).

On the subject of replacing carriages though, it’s actually surprisingly cheap to have a chunk of carriage-sized chunk of 6061-T6 Aluminium carved out for you.

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Maybe the wrong type of bearings anyway?

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Yeah, I noticed that too. I thought I had the wrong bearings. Surely Carbide 3D wouldn’t put $10 radial bearings on a CNC spindle?

But the label stamped on the side is fairly readable and the dimensions match.

One more reason to consider following in Vince’s footsteps.

Though to be fair, the stepper motors were stalling under fairly light load. They might not produce enough torque to cause problems for even these bearings.

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They seem to be rated to above the Nomad speed and well above the forces generated by a Nomad cutting?

Rated for speed and radial forces but Gerald is talking about axial. I don’t see an axial load rating on either page.

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In my other thread I discovered that after adding an ER16 spindle holder, I have 55µm of runout, which is… Not optimal…

I could just deal with the runout but I’ve been thinking about how to retrofit a different Z-axis onto the Nomad. Looking at Vince’s thread, it looks like the things I’d need to do are:

  • Replace the X-axis lead screw with a ball screw. Also a NEMA23 stepper.
    • Make a ball-nut adapter (some simple machining on the Nomad and some thread tapping (by hand))
    • Buy a ball screw
    • Buy a new stepper
    • Buy a shaft coupler
    • Cost: Few hours machining time, ??? for a ball screw + supports, $20 for a stepper (though maybe while I’m here I should go closed-loop) and shaft coupling
  • Rinse and repeat for Y-axis?
  • Replace the Z-axis carriage
    • Buy linear rails
    • Mount linear rails to something (X-axis carriage? New plate attached to X-axis carriage?)
    • Machine new Z-axis carriage (just a 12mm-ish Aluminium plate with some holes in?)
    • Attach new carriage to rails
    • Replace lead screw with ball screw?
    • Replace NEMA17 with NEMA23?
    • Cost: Many hours machining time, maybe a stepper, ~$70 for a pair of linear rails

And then I can mount whatever I want to the Z-axis, even a holder for the stock spindle and its BLDC motor if I want (though I’m thinking 800W watercooled spindle from Mechatron or G-Penny).

@Vince.Fab what do you think? Am I missing anything? In particular, did you upgrade the Y-axis as well? How does that look?

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