[ChrisAttebery]

Hey guys,

I've had my G0704 belt drive up and running for almost three years. I've had a ticking noise coming from the spindle for a while so I replaced the spindle bearings but the noise didn't go away. I'm thinking that the bearings for the 70/60 gears might need to be replaced. I thought that while I was at it I could just remove the gears entirely and just mount a single bearing in a carrier at the top of the spindle. I've seen similar bearing installations on PM-30 type machines but I haven't seen one on a G0704. I thought that it would eliminate one source of noise (the gears rattling on the spindle) and probably eliminate some play and vibration at the top of the spindle since the spindle would be riding directly in a bearing instead of wobbling inside gears. Have any of you tried this?

Thanks,


Chris

[Fastest1]

Is it the gears on the spindle or the quill shaft splines not really fitting the drive tubes mating splines?

[ChrisAttebery]

I think the major noise I'm hearing is a bad bearing on the gear shaft. There's a secondary noise from the the quill shaft splines not being fully supported by the drive tube. Hoss' spacer fixed the secondary noise, but I also think it could be pulling the top of the spindle slightly off center adding to the vibration problem. I'd think that a bearing that supported the shaft directly should reduce both the noise and the vibrations.

[ChrisAttebery]

I pulled the spindle and gear shaft out of the head tonight. The upper bearing on the gear shaft is definitely making noise. I ran the spindle without the gear shaft in place and it's quieter, but not silent.

I ordered a set of replacements from VXB. I think I'll just replace them and be done with it.

[lcvette]

I have considered your other idea of eliminating the drive barrel and just making a bearing holder that fit in the upper bearing hole and held the spindle top for support. I also considered putting the pulley inside the head casting and mounting the motor directly to the head top bit lack of a second mill has held me back from trying it. I have some nasty vibration i think from mounting the pulley to the splined shaft rather then driving the barrel and even though the pulley fits snuggly on the bearing carrier I always wondered how concentric the spindle was to those upper bearing holes. After all it was a quill so there is clearance for it to slide and when you tighten the locking set screw you effectively move the spindle in its bore to the far side. Even if it is just a few thou I imagine it effects it. I think driving the barrel would help and need to pull the trigger on getting away from the timing gears and going to a serpentine type pulley and belt setup or a V belt setup to help smooth things out.

I already bought the SVVCN Lathe tool holder and 35* insert for the multirib grooves but haven't had time to convert the Lathe to cnc to make the cuts and don't wanna even try it manually..lol

I may whip up a single v groove pulley to see if that helps since it appears it would be easier to make.

Let us k ow if you fix the vibration!

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[ChrisAttebery]

I ran a small job routing thin plywood this morning and left out the gear shaft. I was amazed how much quieter and smoother the spindle was. So I changed my mind and decide to make the upper support bearing after all. I ordered a 30x62x16 bearing from VXB. The bearing will have press fit sleeves inside and out to match the head casting and spindle. I'll use a slip fit into the head casting and glue it in place with Locktite sleeve retainer.

[lcvette]

What is locktite sleeve retainer? Do you mean you will allow the spindle to center the bearing sleeve in the head to account for any misalignment from the spindle bore to the upper bearing bore? Of so that is a pretty slick idea, I was unaware there was a product available for that.. Will have to investigate it. Certainly would really quiet things down having the barrel gone completely!

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[ChrisAttebery]

Locktite sleeve retainer will work with gaps up to .009". I'd like to use a slip fit (-.003 or so) and then use the Locktite to semi-permanently attach the bushing to the head.

[TroyO]

Might a carrier block be an option, bolted in place on top of the casting using the factory threaded holes? It would have some adjustability that way. (If I am even envisioning the correct setup, anyway.)

[lcvette]

I considered that too. But it would raise the pulley height up and require remachining motor mounts, Power drawbar set etc..

But maybe if it bolted through the top of the casting and the flange was inside the head with threaded holes... Have to look at it later.

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[TroyO]

Also possibly of note... I ran in to an interesting belt drive conversion on YouTube in which it looks like they replaced the drive barrel with a different one custom made for the job...

https://www.youtube.com/watch?v=_X0Ixi1lHkU

[ChrisAttebery]

I thought about a plate but as lcvette said then the pulleys/motor have to move up. I also thought about mounting it from below but the inside of the casting isn't going to be flat. arizona video makes a belt drive kit that includes a replacement tube for the gears, but his upgrade is about $350.

I had ordered a 30x62x16 bearing this morning, but I was thinking about the fact that I'd have to machine two parts with precision fits in 4 places. Then I realized that I can just use the original sized upper bearing and just make a bushing to adapt it directly to the spindle. The bearing was a light press fit in the head, so it shouldn't go anywhere. Now I just need to machine one bushing. :banana:

[lcvette]

Just make sure the upper bearing bores are truly concentric with the the spindle.

I'm not convinced mine are..

I wish I could cut the splines for the spindle Into a new solid snug fitting barrel and make them nice and close tolerance, still slip fit But not the massive slop in the factory barrel.

I do like being able to slide the spindle out with the pulleys still on up top. Would make bearing maintenance quick and easy.

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[Fastest1]

Bench Top Precision's belt drive kit came with a new drive tube like that. Also I thought about putting the pulleys between the bearings inside the head at 1 time. Still somewhere in the back of my mind. It being so little I am sure the next idea will push it out (of my mind that is)

[Fastest1]

Btw with todays technology, how about some pics? I am imagining this bushing to be in the same place as the Hoss' anti rattle part.

Also could you put say 4 set screws radially around the drive tube to center the now non moving quill? Like a set tru chuck and face plate.Seems like you could adjust the run out with it.

[lcvette]

I have 4 set screws currently on the "CNC" belt drive and my theory is that when I dial them in concentric with he pulley which is concentric with the upper barrel, it is not concentric with the actual spindle centerline. Granted it is very small amount. But none the less my spindle has more the clearance then I would like in the lower bore and the set screw that holds it in place seems to offset it.

If I swap back to the gear drive which I had to do when my bldc driver died, the vibrations were gone. So it could be how its driven. Could be the fact that I am using a timing belt, could be many things.. Bit my theory is to go back to driving the barrel and let it drive the spindle closer to its upper bearing support and to use a multirib serpentine belt to try and keep belt vibrations to a minimum and transfering into the spindle and ultimately the work.

Seems that the play between the barrel and spindle unlinks the two rotating assemblies except for the driving force which is allowed to slip with any concentricity misalignment similar to how an Oldham allows smooth rotation with misalignment.

Working on a new set of pulleys today and tomorrow and will need to find a belt.. Then I hope it is resolved..

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[Fastest1]

I wasnt talking about 4 set screws in the pulley. I was referring to the drive tube of which the spindle itself could go up and down in. Adjusting them could center the spindle itself, solidify it and eliminate many issues, maybe.

[lcvette]

You mean the quill bore? Lower section? Possibly yes.

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[ChrisAttebery]

I'm eliminating the quill drive altogether. I'll keep the upper quill drive bearing in place and use the bushing to support the spindle in the bearing. My pulley attaches directly to the spindle.

Btw with todays technology, how about some pics? I am imagining this bushing to be in the same place as the Hoss' anti rattle part.

[Fastest1]

Or are you eliminating the drive tube?