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Brown and Sharpe 510 questions

Brandenberger

Hot Rolled
Joined
Sep 19, 2017
Hi,

Been trying to diagnose a surface finish problem with my B&S 510 surface grinder.

IMG_1658.jpg

I've tried several wheels, fresh diamond, etc., and the finish is good other than a small x-axis chatter which is diminished if I traverse very slowly in the x-direction. There were several potential sources... including a single phase motor which is rigidly mounted to the motor platform. I have the old GE 3-phase motor and I'll put that on a VFD and see if that helps.

However, to diagnose I indicated the spindle and found .0001" runout. So I've pulled the spindle out of the machine and when turning the spindle slowly by hand, there's a particular spot which doesn't turn as smoothly (feeling like there must be an imperfection in the bearing) always at the same rotational position. At this point the indicator jumps the .0001", then slowly returns to zero over the 360 degree rotation.

I'm guessing other than using it as-is (which seems to produce good parts, just not great surface finish), the only answer is pulling apart the spindle and replacing what are expensive bearings? Anyone know what the bearing specification is for this spindle?

Curiously I note there's a hole on the top of the spindle toward the rear (which would only be accessible when the spindle is removed), and there's a Felt Wicking in the parts manual (part 466-178) which seems to be in that location. See picture with red circle.
IMG_1682.jpg

The manual says the spindle is greased for life... so I'm assuming this wick isn't mean to be oiled. I wonder what this is for? Maybe for air pressure balancing as it warms and cools...

Final question: anyone have a good source for the O-rings (part 466-64) for the oriflex drive? I've talked to B&K, they want $24 for each of 6 O-rings. I ordered some from MSC, but unfortunately theirs are standard .275" cross section, while the B&S ones are some proprietary maker apparently and are a true .250". I've looked at standard metric sizes as well, no dice.

Thanks,
-Phil
 

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Have you tried Sopko? They might have the o rings. Or maybe orings.com. By the way, what is the exact size they should be? Id x dia. My 510 o rings should be changed too.
 
Have you tried Sopko? They might have the o rings. Or maybe orings.com. By the way, what is the exact size they should be? Id x dia. My 510 o rings should be changed too.


My pulleys measure ~.267" width of the channel per o-ring.

The o-ring I got from "oringsandmore" (amazon) and MSC were ~.276". These are MSC part "AS568A-433 10/PK BUNA DURO 90 O-RING". The "oringsandmore" Buna O-rings # 431-90D. Note I tried two OD's (more on that below).

The ones that came on my B&S 510 are worn but show ~.239".

With the new ones from MSC or oringsandmore, they're very tight in the channel, essentially
have to be forced in. The originals are somewhat loose.

The B&K tech wouldn't tell me the exact dimensions, said they were proprietary made for them. He said the standard ones would be too wide a cross-section.

As for OD of the o-ring, that dimension seems slightly less critical because you can adjust the motor mount somewhat, however I found the 431-90D to be slightly smaller than the original B&S ones, the AS568A-433 seem more accurate in OD (but not cross-section as discussed above).

-Phil
 
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I would try Sopko, they rebuild spindles, arbors, and sell lots of 'stuff', etc and have been very helpful to me in the past. Thanks for the o ring info. Now I'm curious to measure mine.
Keith
 
pulled the bearing retaining nut

I was suspicious and optimistic that there was grinding grid in the
spindle dust guard, which to be removed requires the bearing retaining nut
to be removed.

I removed that (LH thread, btw), and have now exposed the front of the
bearing. Unfortunately the labels are on the back... however much
if not all of the roughness at one point of rotation is gone now. Still has .0001 - .00015" runout, but smoothly sweeping that range, without a bump.

Looks like a 62mm x 35mm bearing, presumably 7007-type.

The bearing to an untrained eye actually looks OK.

IMG_1683.jpg
 
Just checked my o rings. First, there's only room for 5 and they appear to be about .260". I'm wondering if my pulleys aren't original. Maybe this would be a cheaper option.
 
Just checked my o rings. First, there's only room for 5 and they appear to be about .260". I'm wondering if my pulleys aren't original. Maybe this would be a cheaper option.


The older pulleys were 5 O-ring I think... the manual I have actually shows 5 grooves. Mine have 6, perhaps a newer machine.
 
You are right, my manual shows 5 o rings. My ser # is 523-510-287. My machine is in a tight corner making hard to access from rear, but miced the o rings again and got around .260" again. Any idea how much tension there should be on the o rings? Looks like I would have to pull shims to tighten or vice versa. Let me know what Sopko says.
Keith
 
You are right, my manual shows 5 o rings. My ser # is 523-510-287. My machine is in a tight corner making hard to access from rear, but miced the o rings again and got around .260" again. Any idea how much tension there should be on the o rings? Looks like I would have to pull shims to tighten or vice versa. Let me know what Sopko says.
Keith

Mine is 523-510-789. The B&K tech mentioned the orings should be so tight they feel like they won’t go on, but do.
 
Well my bearings were stiff and made some noises so I pulled them.

They are New Departure Q0L07 DTX 7097.

Decoding this from the NDH information, this seems like it is

Duplex tandem mount,
Medium preload or maybe light preload (L) or medium preload (X)?

I see a few of these on ebay, but no matched pairs, and I'd worry a bit
about shelf life of what are probably 30-50 year old bearings at this point...

Anyone have a suggestion for suitable replacement?

Thanks,
Phil
 
Cleaned, re-greased, and installed bearings

Having cleaned the original New Departure bearings completely, they felt and looked OK. So I re-lubed them with Kluber grease and re-installed them.

Also put a VFD on the original 3ph GE motor and changed the bearings on that. It runs nicely now.

Now I just have to put the whole thing back together and try it!

-Phil
 
Thanks for posting your project. Looking forward to hearing how it grinds. How hard was it to pull the bearings? Did you find new o rings?
Keith
 
Thanks for posting your project. Looking forward to hearing how it grinds. How hard was it to pull the bearings? Did you find new o rings?
Keith

Got the VFD and motor driving the spindle last night and it is super smooth and quiet. Runout is .0002” on the taper. Now to just get the VFD enclosed so it can survive grinding dust!

Pulling the bearings wasn’t bad— a bearing separator pulled them just fine. In hindsight heating the housing would have made getting the spindle and bearings and spacer out easier too. The spacer was slightly scratched by the bearing separator so I stoned it carefully since the tolerances should be close.

I used the lightbulb trick to heat the inner races to reinstall... 150degreesF was enough for them to drop on. Heating the housing of the spindle to 120degreesF was enough to make the outer races and spacer slide right in nicely on reassembly.

Phil
 
The VFD is up and running and the grinder is grinding. After cleaning and re-greasing bearings, switching to the 3ph motor itself with new bearings, the surface finish is still not fantastic. I don't have a way to measure the surface finish, but so far the best finish is on hard steels (e.g., HSS lathe tool blanks). Softer stuff seems trickier with the wheels I've tried so far.

taper runout is .0002", and with my best wheel hub mounted the flange face runout is .0001" or so.

The patterns I see are 2 effects:

- short scratches parallel to the wheel rotation, which are spaced front to back approximately at the distance of my in/out feed rate. I assume eventually I'll work out a wheel truing technique which conquers this.

- chatter marks which look like minute wheel bounce.

What I'm finding is that there is essentially no vibration of the machine when no wheel is on (with or without the wheel hub mounted), but as soon as I put a wheel on and true it then re-check vibration, there's clearly some felt vibration on the spindle housing, wheel guard, and table. Not enough to make ripples in a dish of water, but easily felt. Much less than before I cleaned the bearings, but still there. The 3ph motor vibrates a bit, but is on a resilient mount with a vibration isolator pad, and so essentially no vibration is transferred into the machine itself from there. When the wheel is mounted there's a low frequency hum as well that's not present without a wheel.

People seem to say "you shouldn't need to balance the wheel" and "you shouldn't need to dress the faces of the wheel" but my experience seems to be different. This is a 7" wheel in all cases. One is a norton 32A46J, another a norton SG 60-K. I can see the faces of these wheels are typically .050" or so out of perfectly tangent to the spindle axis.

I think I should "solve" the vibration problem first? In that it has to be having a negative effect, even if some other factors are also contributing?

So, my questions are...:

- do I just need to balance the wheels? I can turn myself a balancing arbor and try it out across my leveled lathe ways. I could also try a much smaller radius wheel I guess, though that changes another variable.

- does it sound like the spindle bearings are abnormally sensitive to vibration? They sound good, but could be worn to the point where maybe they can't resist wheel bounce as well as they should?

- finally, this is a roller-bearing machine. I made new rollers out of TGP rod since the old ones were badly worn (good material, the radius is consistent to at least .00005" according to my mic). The table movement is smooth, but there is some underlying wear to the roller ways. In particular, when I roll the table fully left to right, I can see in one particular area the rollers will lose complete contact with the table and bed roller ways, and then "catch up" within 1/4" or so as the table continues to traverse. This may create some impact but it seems hard for me to measure that effect. I didn't regrind the table, and if I put a .0001" indicator on the table surface, it doesn't register anything interesting, so I'm assuming the roller ways (8 rollers on each way) average out the wear effect fairly well.

Unfortunately I don't have another grinder around to compare to, otherwise many of these basic questions could be answered through comparison!

Thanks,
Phil
 
I don’t often balance a 7” wheel but that cant hurt. Dressing also both the front and back of a wheel can help if needing better finish. I like to clan a roller way machine very well then run a strip of masking tape at the parting line between the table and base to make an additional dust shield, with one side of machine oiled so tape sticking on the one side. yes one can paint that tape and nobody knows it ts there.
Good hand push under an indicator to everything to see all machine parts are tight/solid. Have thought some table bounce even in a brand mew ball or roller table, .but most often not enough ti see on a tenth indicator..

See the wheel ID fits the hub worth adding a shim strip if needed round OD of hub..

Be sure your RPM is right perhaps 34 to 3600 for 7".

I remember the 510 has long travel rollers..what about the cross travel? rollers also?

Drip,pump or just hand spray bottle coolant can help final grind...just a little laundry soap in a glasswash bottle can be enough.
 
I don’t often balance a 7” wheel but that cant hurt. Dressing also both the front and back of a wheel can help if needing better finish. I like to clan a roller way machine very well then run a strip of masking tape at the parting line between the table and base to make an additional dust shield, with one side of machine oiled so tape sticking on the one side. yes one can paint that tape and nobody knows it ts there.
Good hand push under an indicator to everything to see all machine parts are tight/solid. Have thought some table bounce even in a brand mew ball or roller table, .but most often not enough ti see on a tenth indicator..

See the wheel ID fits the hub worth adding a shim strip if needed round OD of hub..

Be sure your RPM is right perhaps 34 to 3600 for 7".

I remember the 510 has long travel rollers..what about the cross travel? rollers also?

Drip,pump or just hand spray bottle coolant can help final grind...just a little laundry soap in a glasswash bottle can be enough.

Thanks. The cross travel ways are not roller, they're a big V and flat
way and the whole upright section rides on them, all 400lbs or more of it, driven by a leadscrew through a nut. I had taken that all apart, cleaned and stoned those ways and they slide nicely. Some minor scratches from prior owner damage, but the surface area is so big it's hard to see that mattering once stoned.

The RPM on this machine should be 2800 with this "oriflex" (o-ring) drive. The motor is a 3450RPM and the motor pulley is marginally larger than the spindle pulley. Admittedly I haven't put a tach on it to check yet.

Thanks for the suggestion of the tape... I could definitely see grit getting in there otherwise.

-Phil
 
V on cross then you might try this. Bring the long travel to the stop going to the left.Provide a hard stop if the machine has a spring stop. .To the go direction, so it can go no more that way with following the push of the wheel. .. Set a piece of CRS or hard as that doesn't matter. Now travel cross back and forth with a light down feed at each end of part..This is a good way to tell how good your spindle is grinding..Also watch the spark-out as a better spindle will spark-out soon.

You might check your wheel mount front face.. it should not run out much or you will have face wobble in your wheel.
I like to make a small file mark on the nose of my spindle. Then with a carbide or ceramic tool bit turn my wheel mount true to the spindle when it is mark to mark spindle and wheel mount on the spindle nose. Yes only good if using mounts on only one machine.

2800,so you can run most 8" wheels...But?
Might the belts pulleys be reversed to make 3400?
https://www.sterlingmachinery.com/m...grinder-510v,612v-and-618-series-brochure.pdf
 
Hi,

Unfortunately the shaft diameters on motor and spindle are very different
sizes, so can't be switched. It I wanted 3600 RPM with the VFD, I could boost the
frequency > 60hz and that should work.

Here's a picture of the current surface finish.

Nice idea about leaving the long travel fixed, and test out just the
cross travel. I'll definitely try that.

Thanks,
Phil

IMG_1702.jpg
 








 
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