New Toy s/h RF45 Mill

Not that you'll probably need them since you've got your head open but here are some pics for reference.

Turns out my motor shaft seal was already damaged but it never leaked from there.

No thanks, those pics are really helpful - I hope I managed to order the correct oil seals.
 
While you're in there, might as well replace these 2 seals as well as the one for the motor shaft since you're replacing that bearing. The ones circled (2 stacked on top each other) prevents oil leaking onto the spindle/quill. I just had to replace mine last month.

View attachment 287971

Thanks Darkzero - I think I have ordered replacements for these seals (35x45x10mm Nitrile Rubber seals). I ordered the following bits to replace all seals and bearings (including the two motor bearings as there is an annoying squeak from one):

2 x NSK 6205ZZ Metal Shielded Deep Groove Ball Bearing 25x52x15mm (6205ZZ-NSK) = £11.68
3 x NSK 6003ZZ Metal Shielded Deep Groove Ball Bearing 17x35x10mm (6003ZZ-NSK) = £12.57
3 x NSK 6007ZZ Metal Shielded Deep Groove Ball Bearing 35x62x14mm (6007ZZ-NSK) = £24.27
1 x Timken 30206 Metric Taper Roller Bearing 30x62x17.3mm (30206-TIM) = £13.19
1 x Timken 30207 Metric Taper Roller Bearing 35x72x18.3mm (30207-TIM) = £16.45
2 x NSK 6202ZZ Metal Shielded Deep Groove Ball Bearing 15x35x11mm (6202ZZ-NSK) = £7.58
2 x 35x45x10mm Nitrile Rubber Rotary Shaft Oil Seal R23 / TC Style (35x45x10_TC) = £6.24
1 x 75x90x8mm Nitrile Rubber Rotary Shaft Oil Seal with Garter Spring R23 / TC (75x90x8_TC) = £6.67

Not certain about the last item (seal for the end of the quill - I couldn't find a 75x90x6mm seal to match the Grizzly specified part - so this one is brought on spec to see if it might fit, otherwise I will reuse the original that looks ok. I think this seal is really a dirt/dust seal and not as critical as the gear box oil seals.

No doubt that the Timken and NSK bearings will be a good investment and should last a lot longer than the originals.
 
Not certain about the last item (seal for the end of the quill - I couldn't find a 75x90x6mm seal to match the Grizzly specified part - so this one is brought on spec to see if it might fit, otherwise I will reuse the original that looks ok. I think this seal is really a dirt/dust seal and not as critical as the gear box oil seals.

Sounds like your mill will be running tip top when you are done!

Not sure about that seal. I've never taken my quill apart yet so I have no idea. I've only taken the bottom cap off & I dont remember seeing a seal there on mine, just a bearing. But it's been a while since I've removed that cap & didn't look that closely in there.
 
Head stripped and cleaned, in time for the new bearings which arrived this afternoon.

The original bearings were in a shocking state, two were seized and all show signs of internal rusting. The bearings are all marked ZDC, which appears to be decent manufacturer. Not sure if this is the result of fake bearings, casting sand or poor/original/unchanged lubrication - I would have thought even cheap hydraulic fluid would have some rust inhibitors.

288206


288207


Anyway, all's cleaned and ready to rebuild, and pending a new oil sight glass and some ISO68 fluid, I should have this back up and running tomorrow.

I will run it up and through the gears for 6+ hours, and then dump/change the oil again - just to flush any crud that's still lurking between the gear teeth.
 
Dumbass question - all the removed bearings from the gear box had both shields left on, but as this is an oil filled gear box is it not normal to remove the internal facing shields to allow the oil/hydraulic fluid to circulate?
 
Oil will easily get into a shielded bearing. The shield is there to prevent entry of debris into the bearing. Shielded bearings are lubed with oil, while sealed bearings are lubed with grease by the factory.
 
It looks as though the machine was used a few times; the owner suddenly de-materialized, then it sat for ages, in an unheated environment
You'll have a nice unit when you get it back together
Mark
 
I think I read a few articles about the poor quality oil used in these mills along with the excess gritty substance left in the gearbox. It"s recommended to drain and flush them when you get the mill and refill with a quality lubricant. Plus get any sand out in the process. My mill had that same discolored oil in it. You could tell by the clouded sight glass.
Yours looks worse than many pictures I've seen. But it'll be fine once you finished the rebuild IMO.
 
I think I read a few articles about the poor quality oil used in these mills along with the excess gritty substance left in the gearbox. It"s recommended to drain and flush them when you get the mill and refill with a quality lubricant. Plus get any sand out in the process. My mill had that same discolored oil in it. You could tell by the clouded sight glass.
Yours looks worse than many pictures I've seen. But it'll be fine once you finished the rebuild IMO.

Thanks Tim - reassuring and useful advice for anyone buying or sitting on one of these mills - much appreciated
 
It looks as though the machine was used a few times; the owner suddenly de-materialized, then it sat for ages, in an unheated environment

Thanks Mark - I think you're spot on in this assessment, I didn't meet the owner in person but he was described to me and it certainly looks like he brought the mill, mounted a 4" vice and only did a little drilling (judging by the clean spot underneath the vice had never been moved).

Oil will easily get into a shielded bearing. The shield is there to prevent entry of debris into the bearing. Shielded bearings are lubed with oil, while sealed bearings are lubed with grease by the factory.

Cheers Mike - all of these were listed as shielded and pre-greased, so should let sufficient lube in and help keep any big contaminants out. The manufacturers blurb on the website was a little vague:

Metal Shielded Deep Groove Ball Bearings: One of the most commonly used bearings, these types are manufactured with metal shields inserted into the outer raceway, these fit in closely to the inner race providing protection against light mechanical damage, some protection against the ingress of moisture, dust and other foreign matter and serve to retain the pre-filled grease in the bearing.
Shields can be removed for applications that only require 1 shield
Benefits: Provides light mechanical protection, limits moisture and dirt ingress, lubricated for life, cost effective solution
 
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