[rmtucker]

Well it's been a long time since i posted here but i am starting another spindle project and i thought i would share my experiences.

I have been using a 8,000rpm - 28,000rpm Router like most people but had the following problems:-
1.Everytime new bearings were fitted i had to play with shims to prevent endfloat.
2.Bearing life was very short due to vibration and over revving them.
3.Lack of power at any speed below max rpm.
4.Runout on the ER16 adapter i am using was excessive.

After hunting around i eventually found a guy that can supply ER16 extensions that have a step at the bottom to retain the bearings.
This cost me all off £26.00 so it was worth a go.



Let me know what you think initially?

Regards
Mark

[rmtucker]

I have decided to try 3 deep groove ball bearings insted of the usual angular contact bearings.
The reasons for this are cost and Max Rpm,The spindle cartridge in total will only cost around £40 excl the machining of course.
Also other than the problems mentioned in the prev post the router bearings were never a spot of bother if changed regular.
I would imagine in this instance that the bearing life will be far greater (Higher quality and faster bearings,also the rigidity of the housing and less runout).
I have attatched the drawing for the spindle body.

[rmtucker]

This is the drawing for the front cover of the spindle which also holds the front lip seal.

[rmtucker]

I have also picked up the following items.

2 off - 25mm ID x 35mm OD x 7mm thick double lip seal.
1 off - Aluminium Pulley with guides 20 tooth x 5mm pitch
3 off - 6804zz Deep Groove Ball Bearings

I should start the machining in the next few days,i will post pics as i go along.

[ger21]

What type of motor do you plan on using?

[rmtucker]

The usual cheap Treadmill 2.5hp motor with 7,500 rpm.
This will be 1:3 on the pulleys so it could achieve 22,500rpm even though i want to max out at 18-20,000rpm.
I even contemplated going 1:6 using an idler and this way i can stop the motor going into orbit.
I have the motor and DC controller working through PWM on mach3 using the little opto circuit that was used on the Cnc zone some time ago by J Fettig i believe.

[samakthachai]

Normally, I have found most hobby-spindles could drill or engrave on wood,acrylic or non-metal.:tired:
It's possible or not if hobby spindle can engrave on metal. example steel,brass,aluminium and so on. How many minimum horse powers does it can? Who know that?


Cheers
Samak

[rmtucker]

This is the last of the drawings for the Spindle unit.

Regards
Mark

[rmtucker]

Here is a cross section of the assembled spindle unit.

[tsalaf]

Does the ER extension have a metric diameter?
Can you provide the source for the extention?

Thanks

Steve

[Eurisko]

Mark,

It looks great.

I also plan on making an ER16 spindle, but I think I'll go with the angular contact bearings rather than the deep groove variety.


The AC bearings will handle axial loading better, and 20000 rpms shouldn't be a problem.

Could you please post your source for the ER16 extensions and treadmill motor ?

[rmtucker]

Hmmm Been through this argument before with Angular contact bearings.
I can not find a source for 20mm id bearings that will run up to 20000rpm + for a reasonable amount of money?
I have ran my router for thousands of hours and never had a problem with axial load?
There is only 2 bearings in it but they are run at speeds way beyond there ratings.
I think you are defeating the object of fitting ac bearings on an er16 spindle because the spindle can only hold up to 10mm dia so not a lot of axial load can be applied anyway.
I cut everything from wood to metal and never have any problems other than those mentioned in the first post.
The Dia of the spindle is 20mm and just a nice fit in the bearings.

Regards
Mark

[Eurisko]

Mark,

Don't interpret my ramblings as criticism, I was just thinking out loud...

Your points are very convincing, and duly noted.

[rmtucker]

Pics of the part assembled Spindles.
We are building 2 off with different ER16 extensions,Mine has a step to retain the bearings,the other is a std Er16 extension with no step.
The std extension will have a snap ring to retain the bearings.
We quickly measured both spindles for runout and bothe were less than .0005".
Just left with the pulleys to do and the adjuster for the preload.
Total cost so far is £31 for the spindle so far plus the labour.

[FPV_GTp]

Hi

If bearing life is a issue , have you guys considered a oil mist ( spray ) lubrication system on the High speed spindles

rather than rely on the grease packed inside these bearings you guys are using.

cheers

[Greolt]

I'm following this with interest Mark

[dpuch]

This is an idea I have been thinking about exploring for some time. A nicely ground shaft, and collet taper. All hardened... I'm glad someone is working on it.

AC bearings have the large benefit of being able to set the preload pressure between them. With everything spaced just right... they can run a long time and be very rigid. That requires knowing just how much preload is needed, and actually hitting that target though. With an inexpensive design like this, I imagine it wouldn't be that hard to make a few carefully documenting the changes between them to find the right setup. It would probably take 4-6 spindles... Just a guess.

All this is moot if he is getting the desired performance out of the deep grove bearings though, so someone else will probably have to do that research.

The shaft of the collet extensions are available in either inch or metric
hardinge-workholding
centaurtools
parlec
Most without the steps...

As far as horsepower to cut material... sfcalc as well as some other little utilities. Ok. this only has numbers for calculating metals but still very useful.

For spindle lube, I hear it matters a lot as you get into the higher speeds how good of grease you use, and how much/little you use. Do not over grease high speed spindles, and ideally use grease specific for that purpose. The air mist idea is a good one, but means little more hardware. For the air mist, I would also change to a labyrinth seal design instead of rubber seals. This has the benefit of a positive pressure to keep debris out, as well as helping to cool the bearings a little.

Dale

[andy_ck87028]

The usual cheap Treadmill 2.5hp motor with 7,500 rpm.
This will be 1:3 on the pulleys so it could achieve 22,500rpm even though i want to max out at 18-20,000rpm.
I even contemplated going 1:6 using an idler and this way i can stop the motor going into orbit.
I have the motor and DC controller working through PWM on mach3 using the little opto circuit that was used on the Cnc zone some time ago by J Fettig i believe.

Not having an engineering background, I can only presume that this arrangement requires manual intervention for speed control. Is it possible to utilise a motor / controller arrangement that is electronically controllable without being highly priced?

I'm happy for this to be split off onto a separate thread.

Andy

[rmtucker]

Hi

The speed control is controlled through mach3 using pwm.
The interface is only 1 optocoupler (about £1) to the Beel dc speed controller.
It has been shown elsewhere on the cnczone in the past,i will see if i can find the thread.

Regards
Mark

[OzDragonflyer]

Nice job Mark!

So is the pulley holding the shaft against the spacers and bearings?