Third Machine with 12 volt DC spindle

[Rodm1954]

Those of you that have read my previous two builds will understand my machine naming convention so following on with that tradition Jabott has commenced gestation.

It will be a small desktop machine which can be used on site and I might even be able to convince “She Who Must Be Obeyed” (but rarely is) that I can use it on occasions indoors on a cold night. So for this to happen the machine needs to be constructed from aluminum and have low operating noise levels. Routers are out for this reason and after a lot of research I finally settled on a 12 volt DC brushless spindle. I got the spindle off ebay and mated up one of those motors from the car and helicopter model making sites.

The spindle has a brass body with two stainless bearings at the cutting end and a single bearing at the pulley end. The bearings are rated at 60,000 RPM which is more than adequate for my purposes. The collet chuck is 1/8 th inch and overall the spindle is made very well and the finish is good. I have matched a 12 volt DC variable speed Brushless Motor and the DC power is supplied through a modified 380 watt ATX computer power supply and a variable speed controller. The drive is an “O” ring which seems to be a limiting factor in the design. The “O” ring distorts above 25,000 RPM so they just don’t make them like they did when I was a lad – actually when I was a lad I don’t think they were invented but lets steer clear of that one. Measured at the collet the top speed is 35,000 RPM but I suspect some slippage in the “O” ring at this speed.

Although it looks like a toy this is one serious spindle capable of destroying most things in its path. I have done a couple of freehand cuts and drilled a few holes and it is going to perform well for its intended purpose.

I have attached photos of the spindle and the components for the three axis.

My machines evolve more than are planned so here are the details and ideas I have for the axis. It will be a moving gantry design with a cutting envelope of 300mm by 200mm by 70mm.

X axis is a THK KR30 actuator with a 6mm pitch ballscrew and I have 2 IKO LWLF42 linear slides to go with this.
Y axis is a THK KR33 actuator with a 10mm ballscrew and a pair of THK RSR 12W linear slides. The slides are a backup as initially I will fit the actuator and if this proves to be a weak I can add the slides later.
Z axis will be fabricated from the mini ballscrew and the linear slides. The ballscrew has 70mm travel.

[epineh]

Thats a neat little spindle Rod, I like your convention of naming your machines, I have a few for the router (first one) that I am currently building, but we are not really supposed to swear on the forum...

Russell.

[Rodm1954]

Hi Russell
Jabott is the first name and no doubt I will give it an unprintable surname or two along the way.
I have been following your build with interest. Keep up the good work.

[2muchstuff]

Rod,

I'm currently amassing parts for a small cantilever router and have been considering using one of the brushless motors from the model world. What brand and size motor are you using. I was considering a brushed motor but I like the totally enclosed feature of the brushless inrunners. I would like to use a Dremel motor shaft in a spindle with collet to turn a 1/16'th inch bit if possible to keep costs down. I'm flexible at this point if I can find a better/ lighter weight spindle. Will your spindle accept a bit that small. Is there a brand name to go with it. Thanks.

[Rodm1954]

Hi 2muchstuff,
The spindle I got off ebay seller wolfgang314. Here is the link to the unit I got which came with a 9 volt DC bush motor.
http://cgi.ebay.com.au/TB-450M-High-...QQcmdZViewItem
They are more expensive than a dremel but the quality and finsh is excellent and I do not regret buying it. I have no connection with this seller

I don't have any details on the brushless as it was a friends unit that he lent me to trial on the spindle. The first thing I noticed was a huge reduction in noise on the brushless. He did the elctronics so I don't have any details to help you there.
The spindle will only take 1/8 but perhaps the seller will do a second collet if you ask.

[2muchstuff]

Thanks for the link to the spindle and the information.

[--colin--]

Rod,

Thanks for the info. I've been meaning to build a spindle for my router using an RC brushless motor for awhile, but just couldn't decide on a spindle design. Based on your info, I ordered of of those spindles from ebay.

--Colin--

[Rodm1954]

Hi Colin

I hope you are as pleased as I am with the spindle.

I asked about the brushless motor and it is a 380 Walkera Brushless with a Tower Pro 70A ESC and it was purchased from Hong Kong through Ebay.

A small circuit board was built to talk to the ESC. I am not into electronics so I can't help you with this side of it.

Hope this helps.

[Rodm1954]

I have been working on other projects so progress had stopped for a while.

I have changed my mind on fabricating a Z axis as I have been lucky and got a KR20 actuator with 91mm of travel.

It came with a Vecta motor which I took off and I have just finished making a motor adapter plate for a Nema 23 and have mounted and connected it all up. That is a 276 oz motor on there and I hope it is strong enough to drive that huge screw. I will source a smaller Nema 23 motor before I run the machine.

See the photo for details.

I have also done the motor mounts for the other two actuators.

It has been very handy to have a CNC router to make the mounts. I didn't take a photo of the mount before I assembled it but here is an image created in the software (Vcarve Pro) where I did the drawing.

[Rodm1954]

I have finally got some time tonight to get into the shed. I finished making the base of the machine and have fitted the X rails and the actuator I am using as a drive for X axis.
Photos are of topside and underside.
During the week I connected the Z axis actuator and Y axis actuator - see photo.
Next week I will make the gantry sides and fix the Y, Z assembly to the machine.
I will use a 10mm aluminum plate for the table top.
Should not be too long now before it is finished.

[epineh]

Nice lookin machine Rod, look forward to the finished product.

Russell.

[Rodm1954]

Thanks for the feedback Russell.

I have managed to get a couple of nights in the shed and have reached another milestone so time for an update.

Gantry has been made and the actuators fitted. Final cutting envelope is X 300mm, Y 210mm and Z 90mm. The spindle is mounted so you can get an idea of the scale of it.

This one has been very easy to build with the actuators and I would recommend this to anyone wanting a small machine. I feel like I am cheating in this build because alllignment of ballscrews and rails is already done and six cap screws or so and each axis is fitted.

I still have to fit the plate under the gantry and an aluminum table top.

Looking forward I have an X2 column and head and a larger sliding table that I will marry up for my next CNC project so after three machines I am not finished yet. .