Spindle power for cutting guitar bodies

I’m interested in possibly buying a Onefinity machine, not sure which one.
A concern I have is router or spindle power for cutting hardwoods used in solid body guitars.

I had tried a Shark HD520 and discovered that the 2HP spindle was not strong enough to cut through thick wood, (2" thick pine) without struggling with a lot of chatter even going very slow with the feed and speed, taking very shallow cuts (0.12" at a pass). This was just pine, I believe maple, walnut or oak would have been almost impossible without damage.

The Shark HD520 sellers do offer a 3HP spindle kit for $1,300, which might have been an option for me, however it seems as if the machine wasn’t intended for anything more than for making signs and plaques. The rigidity of the whole machine is questionable, if using for cutting through anything other than soft wood, or for carving/engraving in hard wood.

It would be great to hear from someone who has also used on of the Onefinity machines for similar purposes, hardwoods more than 1" thick.

I value strength and rigidity over size of the work area (bed). I wouldn’t need anything larger than 3’ x 3’.

If anyone could offer some input, share experience or advise me in which Onefinity machine could do the work I described without labored effort (or fear or damaging the machine), that would sincerely be appreciated.

Thanks,
TonyA

Hey Tony,

chatter is unlikely to come from the spindle – at least if it is a real spindle (a frequency-controlled three-phase induction motor) that hangs on a good VFD. If you use a spindle with 2.2 kW mechanical power at the shaft, and two magnetic poles which means about 0.9 Nm @ 24,000 rpm @ 400 Hz, and you have chatter, usually it’s the CNC machine that is the weak spot (unless you exaggerated with some cutting parameters).

You say “2 HP” spindle but be careful, some chinese manufacturers write e.g. “2.2 kW” on their spindle but do not mean the mechanical power available at the shaft, but only the so-called apparent electric power. The real mechanical power is much less then. See here for details.

Also when milling wood, it is important to have high torque at high speed (up to 24,000 rpm). Unlike metals, wood has a poor thermal conductivity so tends to get hot, and when milling wood, the heat is evacuated nearly exclusively with the chips. Have you already seen this video? Look at the rotational speeds, they mill everything with high speeds.

For the difference between router and spindle see here.

Welcome to the forum!

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PS: Here you can see a spindle driven to its limits. It’s a Jianken 2.5 kW but as Jianken writes the so-called apparent power on their nameplates, the mechanical power should be someting around 1.8 kW. It is rated 6.6 A but you can see in the video that it is driven to 10 A (on longer duration the VFD would trip then). Also you can see a link to milling black locust with a 8 mm roughing bit with a 6.6 kW spindle.

PS2: Pine is a soft wood, but its knotholes and the dark part of growth rings is denser and harder than a hardwood. That’s why softwood timber with knotholes is only present in the furniture industry since the advent of HSS. Conifer knotholes made hardened carbon steel (as used in handplanes and chisels until the 1950s) dull or break it.

Here’s my experience FWIW. I make guitars on my 1F with very dense woods like Wenge, Purple Heart, Padauk, Hard Maple, etc.

  1. I have a Journeyman model that’s about 18 months old now. It’s on a QCW frame.
  2. I use the Huanyang VFD - 1.5kW 2HP - 110V/120V Input
  3. I use the Huanyang Water Cooled Spindle - 110V 800W 24000RPM
  4. I use mainly Amana bits @ 18,000 RPM
  5. I tend to follow the rule of cut depth no more than 1/2 bit diameter. I often go a little less.
  6. Feed rates are typically a little lower than Amana’s suggested rate.

Overall, my milling takes a bit of a conservative approach. I’d rather get a great cut on an expensive piece of wood than try to save a little time.

I’m building one-off instruments, so batching out a bunch of Tele bodies or similar is not my thing. If that’s what you want to do, then my little setup may not be relevant. But for accurate milling of custom instruments, the quality and performance has been excellent. Recent examples below. All bodies, necks, fingerboards, etc cut from rough stock on the Onefinity. Hope this helps.




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Similar to @karma, I started using the 800w (1hp ish) spindle and later upgraded to a 2.2kw (3hp ish) spindle and have used both to mill guitar bodies and necks out of many different hardwoods. The main difference between them is the 2.2kw can do it faster which might make a difference if you’re going for higher production rates but for one off type applications either can work.

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Those issues with pine suggest some serious errors with setup or programming. At 0.12 inch per pass even a lowly trim router should have no issues.

@karma do you use your cnc for fret slotting or a saw? If cnc, what bit(s) do you use?

Thanks!

I have an X35 Woodworker
90% of my work is in kiln dried british oak the other 10% being ash beech or maple profile cutting and area clearance
I run Huanyang Water Cooled Spindle 1.5kw 2hp
1/4" down cut or compression usually Amana or SP Tools
19.000 rpm
Profile cutting full tool width
70" per min feed rate
30" per min plunge rate
2.54mm step over
4mm depth of cut
Apologies for the mixture of units
Timber secure to spoil board using painters tape and CA glue
Chip evacuation is important I use a combination of dust extraction and also compressed air jets
I tend to treat suppliers feeds and speeds as a guide and a starting point and amend to what gives me a good finish good tool life and time balance as a lot of my items are production runs sometimes 200 of
One particular job that I make many hundreds of is from 5mm oak profile cut full cutter width and I use 1/8" bit compression bit
75" per min feed rate
30" per min plunge rate
2.5mm depth of cut
again apologies for the mixture of units
Trial and error is the way forward but only change one parameter at a time.
The biggest down fall of The Onefinity is not being able to adjust feed rates on the fly it will probably this that prompts me to move away from the Onefinity product, I own and run an Ortur laser engraver which I run with lightburn software which allows you to increase and decrease both feed rates and laser power yes you have to have the machine linked to a pc, and I would willingly do the same with the Onefinity as I usually control the machine over Wi-Fi from my usual bench in the workshop.

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@Mitch I cut fret slots on the CNC and use the MM3I8-0230-009F from Precise Bits.
Hardwood Inlay, Fretting and Contouring Cutters- 3-flute up-cut end-mills (precisebits.com)

The 0.023" diameter matches up with the tang on various StewMac fretwire.

I’ve also used other cheaper bits and they work fine too as long as you cut very slowly with shallow passes (15 IPM and 0.08" depth). Takes like an hour and has been super accurate for me.

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Thanks very much for these replies, very helpful. Using amana bits, specifically a 1/4" straight plunge bit (and also used an amana 1/4") down cut spiral and taking it slow at 20 ipm and around 12000 rpm, the machine struggled at times with soft clear pine.

The tech support suggested I cut shallower at 1/16" and increase feed rate to 80 ipm with a high rpm. I’ll try increasing the rpm’s as you suggested.

I’m not going into high production, just a few custom designed items (around the size, thickness of guitar bodies, but not specifically guitar bodies). I’ll add a pic of an unfinished proto design of what I’m making. (It is 1.5" pine, it will be a percussion instrument using piezo sensors, etc.)

I’m thinking about one of the Onefinity elite models, in conjunction with maybe a PWN spindle, if they have a 3HP model.

Really, thanks for that detailed info, very helpful and appreciated.

TonyA

Here is my son holding the prototype percussion instrument I’m working on. 1.5" pine. When cutting those circular pockets the Shark had no problem using the feed/speed of 20 ipm and around 12000 rpm with a 1/4" straight amana bit. It was when cutting the profile that things got very noissy and, vibration and chatter.

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Yes, maybe I’ll try increasing rpm’s and feedrate as suggested. Up until now I have only used a Tormach 770, which is a very different kind of machine, not really intended for woodworking.

Mitch,

When I first started making instruments I used to cut everything by hand. Rough cut neck on bandsaw then clean up with a handheld router and a template, then cut the fretslots with a stew-mac fret saw, using their fret ruler and a square. I would do the same thing for solid guitar bodies, bandsaw, and hand router with template. That was the hard way, but it was good to learn that hand tool method of making things.

If I had a cnc back then, I would have went wild with it, would have made all parts with it.

I’m not making guitars anymore, but instead electronic and MIDI instruments made of wood. I haven’t done any traditional guitar stuff with the cnc yet, except cut out flanges for custon guitar pickup bobbins.

Thanks,
TonyA

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@TonyA - That’s a great project. Puts me in mind of the old Zen Drum or SynthAxe that Future Man uses with Bela Fleck.

One thought, if you get noise and chatter on the profile cut, there are two things that could help. One would be to switch to an up-cut bit so the chips evacuate the cut better. The other would be to do the profile cut as a two sided job, cutting half way through from each side. That’s the way I cut profiles on thick bodies and have no issues of any kind. Just some thoughts. Hope you find a good solution that works for you.

Thanks. I will try the increased rpm, I was cutting at a less rpm than 18000. I see now why it must be higher.

Beautiful instruments. I’m also a bass player. Do you also make your pickups?

TonyA

Darren,

Thanks for this detailed info, very helpful. I am realizing I have been using too low rpm.

Do you like the Huanyang spindle? Where did you buy it? I have seen some questionable sellers, where support in non-existent or limited, and the programming seems to be crazy.

Thanks again,
TonyA

Thanks. I buy the pickups and preamps. For the Padauk and Cocobolo basses, the pickups are all from the Seymour Duncan 1/4 pound series. The maple/purple heart bass has old school Bartolini’s in it. All three have Audure Preamps (which I totally love).

I see. Those woods are some of my favorite. Check out this padauk Tele control plate I made.

Where do you get your wood?

Tony
I am really pleased with the Huanyang spindle and VFD, I imported it direct from china complete kit, spindle, VFD, collets, spanners, water pump, water pipe, aircraft connector, only things not supplied were a water tank and spindle cable. I cant remember the suppler name but will try to look back through my invoices.
I didn’t worry too much about tech support or lack of it VFD’s are not too bad to programme, it came pre programmed with a fairly comprehensive instruction book, I altered a couple of settings when I first set it up and haven’t touched it since.
Shielded cable from the VFD to spindle is a must, I went with clear pipe and an inline flow indicator along with high quality coolant an enclosed coolant tank complete with a UV aquarium lamp to zap any bacteria.
Some days the spindle will run for 8 hours, i don’t tend to power it down when changing timber I use a large safe y distance, I have got a break out board for the controller but as yet haven’t linked the VFD to the controller the VFD has a rotary rpm knob which I leave alone and just use the Start Stop Buttons, It would be a nice to do but my work flow works fine without it. The VFD is wired on a separate supply to the Onefinity.
I have a need to develop and build an in bench router table and lift and will look at using a similar spindle and VFD set up due to its low noise and ability to run all day,
Hope this helps

D

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Nice plate! I typically buy wood from three places. Two in NC and one in WI.

Steve Wall Lumber
West Penn Hardwood
Ocooch Hardwood

All three have been great with quality, shipping and customer service.

Let me know if you need some drummers to test it out! Wink. Looks like a Future Man kind of set up. Very cool.