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0-1 Rc 63 cylindrical grinding, wheel recommendation

PANTERA79

Aluminum
Joined
Feb 22, 2011
Location
south carolina
doing an operation on my #2 Brown & Sharpe universal, grinding the end of .875 diameter hardened tool steel, 0-1 only removing .005-.007 needing good finish. Have a fair finish now would like better. Been using Norton 45 grit gray speckled wheel, tried a finer milicron pink wheel, 10-times worse.. now getting hot spots no matter what I do with pink wheel. This is a production job, 800 pcs at a time. Need advice on best wheel that I don't have to dress every 5 parts and still get best finish possible as I'm not very exp. with cylindrical grinding. Thanks guys.
 

eKretz

Diamond; Mod Squad
Joined
Mar 27, 2005
Location
Northwest Indiana, USA
What hardness wheels are you running? You say "best finish possible" but that's very subjective. Are you looking for a mirror polish? That's not going to happen on the grinder. You need to be more precise with your words. What is the actual finish requirement?

To start I might try a 60K or 60L if you have one.
 

gbent

Diamond
Joined
Mar 14, 2005
Location
Kansas
When you say "grinding the end", is it a diameter at the end on the pin, or the end of the pin? Tell us what specific wheels you have tried, grit and hardness. What is the surface finish requirement? Do you have a actual roughness spec, or just "better than this"? Can you post pictures of the setup and the finish?
 

michiganbuck

Diamond
Joined
Jun 28, 2012
Location
Mt Clemens, Michigan 48035
When you say "grinding the end", is it a diameter at the end on the pin, or the end of the pin? Tell us what specific wheels you have tried, grit and hardness. What is the surface finish requirement? Do you have a actual roughness spec, or just "better than this"? Can you post pictures of the setup and the finish?

And add tolerance. plus are you plunging straight in with cross to size, or using some long travel, How are you holding it, is it a long stick-out part or stubby, on the tail or chucked, , wet or dry? Im only removing .005-.007-> how many seconds on the part?? usually like a 60 gt or smalled for much hard OD steel. White AO wheel is usuall good enough and having a wide enough wheel straight in often is good.

One really good trick for a 600 piece part is to have a solid off-the-table dresser and set it to just barely touch your after a good part wheel location. Then you dress and from that same cross position you back out .010 infeed to dress-spot + .0007 dead-on size. yes, the first part after tha dress is your gauging part to tell you the exact + number.

You might find that you get 3, 6, 12 or 20 parts before a re-dress that takes a half minute to do.

You note that fresh dress + 0007 (or what) makes part size. Sometimes you can run for hours with hardly measuring. After a time you might cross out the .0007 and note Dress + .0008 makes size )A tenths of diamond wear.

I have noted the + amount to equal/spot a tenth or two above my low limit and that way get more parts to going size to a couple tenths under my high limit.

For some jobs have a drop-in stick so you can go away for dress, and then go right back to your stop that tells where tha part location is.

OH, I use a piece of masking tape with an ink pen line to set on my dial, that way I don't need to remember or bend over to eyball my number.
 

PANTERA79

Aluminum
Joined
Feb 22, 2011
Location
south carolina
sorry for being so vague guys,, been a hell of a day, as I lost my mom this afternoon after a short battle with caner.. So here is a pic of my set-up. Angling the heads slightly to give me the acute taper/radius needed. Indicated in 5c collet holder in the chuck, for quick removal, have tried different speeds on the work head. Not looking for a "mirror finish" really, these are lifters, (valve tappets) we are mfg in house. Have had good results with our parts functioning without issue, I'm just looking to improve the "visual" finish. Surface wise they are acceptable and "working" but if you compare to say a factory lifter, I'm just not getting that nice smooth swirl finish like other manufacturers. Right now when they come off the grinder we chuck in a speed lathe and hit the face with a light 400 polishing paper, than scotch pad quickly for improved finish. Just thinking maybe there is a better wheel or method to get a improved product-finishes. And yes, I have better coolant flow than in the pic, slowed it down for better clarity for picture purposes. sorry having trouble loading pictures..
 

PANTERA79

Aluminum
Joined
Feb 22, 2011
Location
south carolina
sorry for being so vague guys,, been a hell of a day, as I lost my mom this afternoon after a short battle with caner.. So here is a pic of my set-up. Angling the heads slightly to give me the acute taper/radius needed. Indicated in 5c collet holder in the chuck, for quick removal, have tried different speeds on the work head. Not looking for a "mirror finish" really, these are lifters, (valve tappets) we are mfg in house. Have had good results with our parts functioning without issue, I'm just looking to improve the "visual" finish. Surface wise they are acceptable and "working" but if you compare to say a factory lifter, I'm just not getting that nice smooth swirl finish like other manufacturers. Right now when they come off the grinder we chuck in a speed lathe and hit the face with a light 400 polishing paper, than scotch pad quickly for improved finish. Just thinking maybe there is a better wheel or method to get a improved product-finishes. And yes, I have better coolant flow than in the pic, slowed it down for better clarity for picture purposes. sorry having trouble loading pictures..


View attachment 346615 trying to upload..
 

michiganbuck

Diamond
Joined
Jun 28, 2012
Location
Mt Clemens, Michigan 48035
Sorry to hear about your mom.

Have you tried a 60 or 80gt wheel?
Wheel hardness can be a factor. too soft and you go from dressed to breaking down quickly and too hard you begin to drag too many material particles with the wheel.
The sharp fact of the diamond is important.

Magnifying 5x looks like you have travel lines on the surface, likely caused by condition of dress, break down, dragging material, 0r grit size. likely those lines show more with a plunge in but they would not be angled.

QT: [tried a finer milicron pink wheel, Yes, I saw that.

Does the grinder produce good finishes on other jobs?

Does the grinder make better finishes when running parts between centers (agree you can't run that part between centers)?

Is your collet making a solid holding? you could tap a part with your brass rod to tell. Sometimes collets get worn out or are made poorly and so act like a chuck with tapered jaws so only holding the very end of a part.

Tapping a collet to tap in a hard part can wear out a collet. Some collets are only Rc 40 or so... and that is good for saving your machine taper if you toss them when they need tossing.

What wheel head spindle do you have? Sometimes putting the grinding wheel on the other end of a bearing
spindle can help if bearings are going bad. Sometimes going a little higher oil can tighten wore out plane bearings.
spindle oil viscoties,
 

eKretz

Diamond; Mod Squad
Joined
Mar 27, 2005
Location
Northwest Indiana, USA
Condolences on your mom.

Buck, I'm not sure if I'm catching the inference correctly, but I think he is grinding the contact faces on the ends of the lifters. ("Grinding the end," "turning the heads for acute taper/radius," "hit the face with 400 grit," "swirl finish," etc.). That pattern on the ODs does look weird, I noticed it also, but it may just be a photo artifact.

If you want to compete with factory finishes you probably need to figure out what wheel they are using and emulate it. Most likely it will be a CBN wheel. Those generally need a lot less dressing too. If you make enough use of the grinder it may be worth looking into. They are a good bit more expensive than an AlOx wheel if you get them from a high quality U.S. manufacturer but can be had cheaper from imports. I like Poltava brand fairly well - but made in Ukraine, so not sure if they're hard to get right now. A domestic maker might know just the wheel you need.
 

michiganbuck

Diamond
Joined
Jun 28, 2012
Location
Mt Clemens, Michigan 48035
Oh, and if yours is a belt drive spindle the pulleys should be checked for balance and OD run out.

Eric, could be he is only grinding ends? Op might state if only the ends or OD is the greater problem. looks like he is showing off the ODs in his photo.

QT: but can be had cheaper from imports. I tried some import/bargain wheels and they went straight into the dumpster after one try.
Import name brands are Ok/good but just as expensive as US-made, and not better.

A photo of setup might be desirable.

OP QT: grinding the end of .875 diameter hardened tool steel, 0-1 only removing .005-.007
 

PANTERA79

Aluminum
Joined
Feb 22, 2011
Location
south carolina
sorry was just trying to give the jist of what we are doing, the batch in the pan was rough ground, and going back to finish op, we have a little royal master centerless for the OD, pic attached. Yes the Old B&S is a belt drive, bushing spindle, pretty decent shape, makes a good finish between centers. And yes, correct I'm only grinding the end face of the parts. I'll take a pic of the finished surfaced, the one I'm trying to improve. The pink wheel I couldn't stop getting hot spots. The Norton wheel seemed to work the best, my diamond is some old 50 yr old diamond, it works, but maybe no good. Again I don't know much about proper grinding applications. For ease of dressing I made a bushing same size as my part od, and drill-reamed a hole for my diamond to fit in with a set screw to speed up dressing, I just don't power up the work head when dressing. The 5c collet holder has a stop in the end so I'm holding my part length with it. I did think about trying a CBN wheel, as I know they are supposed to produce a better finish, but if I can do with a regular wheel all the better I thought..
 

PANTERA79

Aluminum
Joined
Feb 22, 2011
Location
south carolina
sorry was just trying to give the jist of what we are doing, the batch in the pan was rough ground, and going back to finish op, we have a little royal master centerless for the OD, pic attached. Yes the Old B&S is a belt drive, bushing spindle, pretty decent shape, makes a good finish between centers. And yes, correct I'm only grinding the end face of the parts. I'll take a pic of the finished surfaced, the one I'm trying to improve. The pink wheel I couldn't stop getting hot spots. The Norton wheel seemed to work the best, my diamond is some old 50 yr old diamond, it works, but maybe no good. Again I don't know much about proper grinding applications. For ease of dressing I made a bushing same size as my part od, and drill-reamed a hole for my diamond to fit in with a set screw to speed up dressing, I just don't power up the work head when dressing. The 5c collet holder has a stop in the end so I'm holding my part length with it. I did think about trying a CBN wheel, as I know they are supposed to produce a better finish, but if I can do with a regular wheel all the better I thought..

my son running the royal master, infeed set up.276057777_5295642820467529_1385562587593354413_n.jpg
 

gbent

Diamond
Joined
Mar 14, 2005
Location
Kansas
My condolences on the loss of your Mom. I hope you can put this job on the back burner for a little while to allow some personal down time.

How much crown are you putting on the part (not essential, curiosity)?

Wheels aren't cheap so we don't want to make you chase your tail. I didn't see the grit and hardness of the wheels you have tried. The others may have a better handle than I, but generally if your wheel is burning, you need a softer wheel. What is the grinding wheel speed and diameter? The slower the SFM, the softer the wheel acts.

Grinding is one of the black arts of machining. When something isn't right it makes the whole process stink.
 

michiganbuck

Diamond
Joined
Jun 28, 2012
Location
Mt Clemens, Michigan 48035
I take it that you are turning the dressing diamond to a new facet (sharp edge)

QT op: [and drill-reamed a hole for my diamond to fit in with a set screw]
Sp likely you are hitting a new facet

An off-the-table dresser likely/might be a faster way to come to dress.
 

PANTERA79

Aluminum
Joined
Feb 22, 2011
Location
south carolina
not sure what you mean, on the sharp edge of the diamond. This is what I'm using for dressing, maybe some of the problem? Also attached are pic of the 3 wheels I have, the Norton wheel on the machine, which has worked the best out of that and the pink.. is a 32A46-H8VG whatever that means.. the "blue" wheel is unknown, no #'s on it, so I haven't tried it yet. pics are poor quality, sorry, lifter on the right is fresh grind, lifter on left is after polished on the speed lathe. This seems to be a black art for sure! IMG_20220407_140214251.jpgIMG_20220407_140406033.jpg
 

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michiganbuck

Diamond
Joined
Jun 28, 2012
Location
Mt Clemens, Michigan 48035
QTOP: [not sure what you mean, on the sharp edge of the diamond. ]

The diamond gets flattened/rounded by use. Often one will look at the diamond to see that the diamond
is not always wearing in the same place on the diamond.
A flat/rounded diamond burnishes/crushes the wheel.

A sharp diamond Picks the top/high edges to pick off and leaves a smoother clean loaded free surface.

Pointing straight to the wheel when dressing makes the diamond wear into a big radius, so even turning the diamond does not help.

not sure what you mean, on the sharp edge of the diamond.

Best is a 15 to 30* angle to the wheel so wear to the diamond makes flats and so sharp facets are developed.

If your grinding is near flat or only a few degrees off straight and you use the same angle for dressing, then that may be a big factor in your problem.

New blotters can be made of cereal box cardboard or the like. *Always use a good condition blotter, a few spots of Elmer's glue holds them on.

Wheels should be ring tested each time your install or they may blow up.

Good to stand out of the blow-up direction when starting.

Sometimes breaking the wheel edges (corner break radius) with a dressing stick can help for a better surface finish.

Oh, using an off-the-table dresser one sets the diamond holder at an angle to the wheel (about 15 to 30), and turns the diamond to a new facet often..
 
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eKretz

Diamond; Mod Squad
Joined
Mar 27, 2005
Location
Northwest Indiana, USA
So you are basically grinding a shallow tapered cone shape, yes? Almost looks like the wheel is not traveling straight with the dress. The fresh ground surface on the right side lifter doesn't look as flat as I would expect. Looks wavy.
 

gbent

Diamond
Joined
Mar 14, 2005
Location
Kansas
That looks like your dresser diamond setting next to the lifters. It looks completely worn out to me. You need a new diamond or reset that one. Then as Buck says, you need to present the new diamond to the wheel with the diamond axis pointing 15 to 25 degrees away from the wheel centerline. This helps the diamond stay sharp longer.
 

michiganbuck

Diamond
Joined
Jun 28, 2012
Location
Mt Clemens, Michigan 48035
Here is a good/simple explanation of single-point dressing. This site shows how a diamond can become rounded/flattened by using the same place.

http://dk8mx37zdr9bp.cloudfront.net.../CITCO_Tools_Single_Point_Dressing_TipsV3.pdf

Most advise 10 to 15* angle offset(OK), 15-20 is my preference. The angle can be towards the wheel center, or with a table-mounted device just angling the dresser angle.

With a set position/constant you turn/twist the diamond radially by increments to get the next sharp facet.

Back in the old days, before mv time people would un-braze the diamond and re-braze it in another position.

Oh. and it is good to set the diamond to the grind direction (away from rotation), so it does not try to catch/flip into the wheel and so cause vibration. I prefer a 3/8 or larger diameter shank so as to not easily vibrate..and less than a .015 diamond point radius, the sharper the better.

The take from the wheel is often .001 - .002" Less and a tickle is not good, and more might dislodge the diamond.
Some say to lightly bump the wheel with a wood stick or the like after dressing.

After dressing The part finish relates to the wheel grit size, then as it loads up it will finish smoother, then at a point, it will begin to drag down rpm, or cause excessive heat with the grits getting rounded and with the space between grits getting loaded with part material.

A perfect wheel will break down to lose grits, and will self dress for a time so being able to grind for a long time between dressings... but you rarley find that perfect wheel.
 








 
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