Novamill questions

[Mihail]

Dear all,

Could you please share some of your knowledge. I am in process of updating the steppers/drivers and control board on a Novamill from 2000, the original Denstep board was well corroded with loose vias.

How is the spindle rotation direction change implemented in the Novamil? I have a few relays but don't see any in the plan that would do a changeover of the poles.

Also, what is the control voltage for the relays and guard interlock? Is it 28volts and if so, would they operate correctly at 24v?

And, does anyone have a good source for the kg 20B T203/GBA018 power switch? I am missing the outside switch specifically.

And...has anyone found a way of installing am encoder/index signal on the drive motor? seems a bit tight inside unless there are premade mounting points I can't identify yet.

Also, I seem to have a fair bit of backlash in the Y axis, about 5 degrees of movement of the large belt pulley before any engagement of the table, not powered it yet to get measurements of that means in practice but thinking ahead or what I might need to look at to make it better. The other axis seems in decent shape.

Many thanks for your time and help,

Mihail.

[TomJennings]

Hi, Mihail ,
I have some answers, but it would take several A4 pages to tell you how.
1) The spindle doesn't reverse, but it will! you need a spindle reversing Relay (not cheap!).
2) The control circuit voltage is 24v
3)Power Switch. I cant help with.
4)I have installed an encoder, and index on mine, see pictures
5) Y axis backlash. Are the Pulleys tight (loose screws), and is the Belt OK.
I would be happy for you to contact me, if that is OK with the moderator.

[Mihail]

Thank you TomJennings !

Sorry it took me so long to check this page, I had lost hope on getting a reply.

That is quite a setup you have there, very impressive.

Thank you for all the answers.

Regarding number 5, yes, the pulley is tight and I changed the belts with some of identical part numbers.

One more question, what vise are you using? I am struggling even with the small grinding ones to get clearence with the Easy Change and a 6mm endmill.

I would be tempted to overhaul it completely with new ballscrews, saw at some point a post that it is still possible to buy them and then find a place to machine the Z axis riser block and then install the encoder/index pulse like you did it. But in all honesty I am happy with what I am getting so far, but I am mostly making brackets and low precision things and trying not to crash it too often

Haven't managed to get the time to figure out why my soft limits in Mach3 don't work.

Thank you again for your time!

[Akorenika]

I use this vice. https://www.rdgtools.co.uk/acatalog/75m ... ml#SID=354
I'm very impressed by the quality. Had it a couple of years. I don't use the quick change tool holder but ER32 BT30 holders. The combination of the 2 helps with height.

[Mihail]

Thank you very much Akorenica. Will look at it. Sorry for the late reply,need to figure out this forum notifications settings.

Also, I bought a BT30 ER collet holder and discovered the drawbar doesn't actually reach it. Looking at photos it looks more like a INT30 as it has the extended thread for the drawbar where the BT30 normally ends so pretty much stuck with the Easy Change that came with the machine.

[Akorenika]

I don't use a drawbar, just a bolt as I don't have a tool changer. I also just bought some collets that go straight into the BT30 taper. At the moment I have no way to hold the spindle to tighten the bolt but that would give a extra 50 mm or so height.
Here is a link for you.
￡4.73 | 7:24 NT30 tapper collet spring collet chuck Milling chucks Thread M12 for cnc milling machine
https://a.aliexpress.com/_mKahF0w

[Mihail]

Interesting, when I say drawbar I mean the bolt that came with the machine. How are those collets in terms of leaving marks on the taper? did they need a bit of work with a file?

[DavidB]

Mihail,

What about an extension to the BT30 like the person did in this thread https://www.mig-welding.co.uk/forum/thr ... 670/page-3 .

[Akorenika]

Those collets are a perfect fit. They don't leave any marks. They do require a shorter bolt/drawbar, nothing else. The down side is that you can't change tool without re-setting the z axis but for extra clearance they are really good. They don't come in too many sizes either. I have a 6, 8 and 10mm but that's what I use most anyway.

[Mihail]

DavidB, that sounds like a good project for my current project which is a Conect121 Lathe, now more motivated to get it up and running So are they all INT30 or did I get a special one of some sort?

Akorenica, thank you, will be ordering a few, hopefully the tooling they used stayed in good shape.