Accurate Strong Gantry

[vargai]

Why don't you sketch your idea for the spindle and investigate the bearings.

Here is some sketch and I am almost sure the for DIY use with a short 5 mm flute cutter this spindle is quite strong enough.
Cutter is clamped by Weldon @6000 it works, lower AC bearings are coupled and after installation it will be preloded
grease lubricant also fine here.
Some safety issue should be considered:
The drive shaft in the ER20 collet should we carefully machined including the pulley to reduce the unbalance.
I would use double key opposite to each other.
Good cover must be done to protect the belt and user.I checked my 170 mm blade Makita plane , it run @15000rpm so you are of course right regarding the belt application. Here ribbed V belt is used so i think 15 mm wide HTD3 is sufficient here.
If you flip the pulley on the mini spindle to the top to skip the belt from the milling area you have to use some adapter plate .
This is not the first thing i make now but probably later Paris is well worth a mass.

[Boyan Silyavski]

Some technical info and bearing sizes and data . There are some force calculators there and so on. May be you know them already but let be here on one place.


Here is the 3kw/3.2-4kw i believe also/ spindle with all sizes if you dont have it at hand. I took them personally :-) .This is the original Guanzhou spindle with the 4 bearings and the black rings. Maybe enough place that the attachment could be clamped directly at the spindle there.

Hope that helps. When i have time will sit also and see if i have some ideas.








These are the bearings and dimensions of the BT35 spindles for reference:








Here is some belt info. If i read it correctly best would be HTD3- HTD5 belt or GT belt even better . Dont be put off by the lower life the figures show. After all one belt is 1-4 euro only. One thing to note is that wider than necessary is not a good idea.

[Ross77]

The general arrangement is really good. Back to back AC's and floating end bearing to allow for thermal growth. Are you making this or buying?

My only concern is that by driving it from the bottom you are increasing the distance from the cutter to the bearings and compromising the design. The belt tension will also pull the spindle off center. Can you drop the bearings down in side the pulley?

I'll try to find my old spindle designs and show you what I mean, I have gone over sized on the bearings so the taper of the collet is inside the bearing.

what size bearings are they? For 6000 rpm have you considered roller taper bearings?

This is of course me being super picky, your design will work but just offer suggestion to maybe improve :0)

[vargai]

The general arrangement is really good. Back to back AC's and floating end bearing to allow for thermal growth. Are you making this or buying?

My friend is renting a small shop and generally I got him to machine the part,and I will put them together.
There are a Bridgeport VMC, a Colchester CNC turn and a Hungarian CNC turn. I used to work here but recently after the daily office job I prefer to have a little brake. That is way I would like to have some machines at home where I can work any time that fits to me.
The bearing is 15 mm bore -for an entry level spindle is Ok but any design comes in handy, thanks.

PS: I have adjusted my setting so the vid is already visible at my previous post to you

[vargai]

Here is the 3kw/3.2-4kw i believe also/ spindle with all sizes if you dont have it at hand.

I prefer to download 3D model of all stuff and it is not supplied so thank you this and other information.
I will make my model to go further.

If one use this spindle occasionally only for fine milling in steel(up to 3-4 mm flute small doc) there is no point to make extra attachable spindle except handling the main gently.
When I am right the main DIA of the rotor is 25 mm(suppose the bore of the bearing same) so it has much stronger then my mini spindle with its 15 mm bore bearing. At this case I would not rank the spindle application
based on material but based on load.
There are coated cutter for HSM in steel rated for 7-8k rpm. At this value the torque is about 1/3 of the top ( I will check the curve) so this gives an additional protection for the spindle.

I have an offer for both 2,2 and 3 kW Guanzhou spindle and saw the 2,2 kW is popular among builders.
Does the bigger worth the 200 USD price different on a general router-or the bigger the better?

So actually its not a discouragement, its a reality check. I will be more than happy to see it done. Cause i will do it also.

I am agree with the advice to go step by step. A 700x1000 mm commercial LSM CNC mill has a roomful foot print and it cannot be compressed to my design with impunity.By sitting in front of monitor and doing 3D designs some(me) tend to loose the sense of reality. So I go further with a router and it gives the possibility beside other matl to work with wood that I like too. In the mean time I can check things in the reality. I can reach from A to C through B and maybe it will be shorter way.

If you decide to go this way, i will send you the plugin.

I have to jump in to the electric stuffs first to understand completely this language.
I revert it later, thank you in advance