New Motor for G0704 (DC treadmill vs AC Spindle)

[Vogavt]

Adding a tach signal (hall-sensor) to the motor allows mach3 to attempt to maintain the RPM but when I'm drilling with a 1-1/4in drill bit (after a pilot hole) the drill bit stops as the response delay in mach3 can't be avoided at such low RPMs.

Can you give more details about being able to get Mach3 setup to "maintain the RPM" via a tach signal?
Don't want to derail the thread, so you can PM me if you like.
Thanks!

[rusmannx]

While staring at the guts of this thing I just realized I don't need any of this quill assembly. I removed the quill arms when I CNC'd a couple years ago and have never used it since. That's less bearings and rotating mass, so I think I'm going to try it. I can probably bore a pulley to fit right over the splined spindle shaft.....

[websrvr]

Can you give more details about being able to get Mach3 setup to "maintain the RPM" via a tach signal?
Don't want to derail the thread, so you can PM me if you like.
Thanks!

Google has plenty of results for this but since you're having a problem finding one look at this page, it's using an optical sensor but the same principal applies, see: TACH.

boy websrvr you argue and condescend just like dwalsh and are still trying to sell him stuff, how about that, the deep groove bearings you are pi$$ing on that rusmannx asked about DO only take radial loads in this application, so using ac bearings to replace them is complete nonsense, there is no way to apply a preload to them and the assembly they are on MUST handle a radial load, why don't you get what rusmannx keeps telling you, he's not looking to spend loads of money just to get his hobby mill back up and running and understands it doesn't require ultra precision parts to get the acceptable performance needed.

HAHAHAHAHAHAHAHA too funny, a spindle shaft in a mill/drill accept radial and axial loads, if it can't accept axial loading then it can't plunge or drill, this is not my opinion, this is a fact.

My offer to him of precision bearings for his spindle shaft was more than generous and was to help him not spend a ****-load of money on bearings and my offer saved him about $256.00 for a pair of precision bearings that cost $306.00 and would have been a little more than the cost of decent deep-groove bearings so how do you figure it's an excessive amount or "loads of money" as you put it?

Since he has already purchased his bearings (except for two) as he told me, I can understand him not him not wanting to spend more money buying bearings so your comment about selling him stuff are nothing shy of retarded and moronic because until he revealed he purchased bearings after I made my offer, I had no way of knowing before hand.

Since everyone is referencing a top and bottom spindle bearings I made the assumption that these bearings are related to the spindle shaft top and bottom bearings and not an intermediate or counter shaft that has radial forces only and never sees any axial loading, such an intermediate or counter shaft is not normally referenced as a spindle shaft so it helps if the shaft in question is correctly identified to avoid any confusion about it's purpose and now that I know the bearings are not for the spindle shaft itself I agree, the need for angular contact bearings on this shaft is not required, they're not in the quill so deep groove bearings are acceptable.

Now, if he says that the two bearings (6007 and 6209) he still needs to purchase are used in the quill for the actual spindle shaft then all that I said is correct, they should be angular contact bearings for optimum performance and even the cheapest P0 ones he can get his hands on would be better than deep groove bearings.

This spindle is starting to sound like a nightmare in design utilizing multiple shafts, perhaps a better solution is to gut the head and stick in an R8 shaft and belt-drive it, it would be better than the MT2 shaft it currently employs, simplify the spindle design and make future maintenance easier and, I hear rumors that R8 conversion shafts are already available for the G0704 / BF20 / WMD20V / WMD20LV.

[SCzEngrgGroup]

Howzabout you two guys take your pi$$ing match off-line? It's getting really old....

[rusmannx]

Howzabout you two guys take your pi$$ing match off-line? It's getting really old....

Haha, I'd be OK with it.

I think the bulk of the posts in this thread are about bearings, and I'm pretty sure my original post was about drive motors (per the thread title)......

I just checked, and I'm right.

[carlowens]

While staring at the guts of this thing I just realized I don't need any of this quill assembly. I removed the quill arms when I CNC'd a couple years ago and have never used it since. That's less bearings and rotating mass, so I think I'm going to try it. I can probably bore a pulley to fit right over the splined spindle shaft.....

yes websrvr the radial bearings go on the intermediate assembly, there was no confusion because as one g0704 owner, me, speaking to another, rusmannx, we aren't talking about general nonspecific machines, the title of this thread is specific, the g0704. I've taken mine apart and done the upgrades so i DO know what i'm talking about and could care less if you understand it or not, this isn't your thread. to that end, rusmannx, you do need this assembly with it's radial bearings, i've read others who thought as you did and it was pointed out that the upper end of the spindle where you want to attach a pulley for your belt drive is too flexible on it's own to resist the radial load of a belt drive.

[rusmannx]

you do need this assembly with it's radial bearings, i've read others who thought as you did and it was pointed out that the upper end of the spindle where you want to attach a pulley for your belt drive is too flexible on it's own to resist the radial load of a belt drive.

Good point. I am planning on a timing belt set which I would assume needs less radial loading to operate, but I have no experience on the matter.

[carlowens]

Good point. I am planning on a timing belt set which I would assume needs less radial loading to operate, but I have no experience on the matter.

well i went with hossmachines plans a couple years ago so it made it easy to understand and did the timing pulley too but the belt still needs to be under tension, maybe he'll chime in again with more specifics. i've seen other people make belt drives too that made use of the quill assembly also to take the radial load from the belt tension, ones that tried too without the assembly got lots of vibration. i saw there is someone in new zealand making belt drives that might be worth looking into.

[Al_The_Man]

Can you give more details about being able to get Mach3 setup to "maintain the RPM" via a tach signal?
Thanks!

I don't use Mach, but have followed its progress over time, I believe you will find that the spindle 'Tach' is a one/rev signal that is used to keep the Z axis on a lathe for instance in sync for threading, this is it does not control the spindle, per-se, but monitors exactly what the apparent rpm is in order to sync the Z, in a commercial or upper-end system, there is a proper incremental encoder on the spindle of which the Z is electronically geared off of.
Al.

[Vogavt]

Gotcha. I misapplied my reading of the word "maintain". I understood you to mean "control" but you intended it to be a "placement" of sorts (I guess).
In other words, the reading is maintained on a display.

I have that already in Mach3, but thanks for clarifying.