grinding slots wider than wheel

Most of the grinding I do is flat to size or sharp edges. So I'm not sure if I forgot or never learned this.

I have to grind some .375 wide slots about .25 deep.
These were roughed out before heat treating.

With about .010 on each side is it better to plunge the wheel or feed in from the side or combination.

I'm using a 1/2 wheel dressed to about 5/16. Bottom of slot is not critical.Both sides of the wheel are relieved about 1/8 from the bottom of the wheel.

I have a digital readout but no real fine feed on the cross. So it's light taps to adjust.

Dave

I don't know the material or the grinder you are using but....after dressing the wheel go to full depth and feed sideway.
Important! After dressing the sides of the wheel - loosen the wheel nut - not the spindle nut - and than turn the wheel on the hub and tighten. This will let the wheel wobble a little bit so it won't glaze right away.

That's a new one on me.If your wheel is working fine on the periphery it should be fine on the side. Remember, very light cuts on the sides.

Winger, A couple of questions, what is the tolerance of the slots? What material, what wheels etc. For ME, I use both methods depending on dimensional tolerance, and finish requirements. Plunge grinding will give a better finish, USUALLY, and reduce the bell mouthing at each end of the cut, HOWEVER, the corner will break down, and you will need to dress the corner prior to final depth. I ALWAYS put a piece of scotch tape, on the floor of the slot, and color it with a sharpie, to indicate when I am getting close to the floor. re color it, each time you dress the wheel.
Side wheeling will produce the swirls, and a good finish depending on the amount of step over, my concern, is, you mention "light taps to adjust" just be really mindful, and hopefully your readout is in tenths..
I too, was taught to loosen the large diameter wheel nut, to prevent glazing. additionally, if the wheel is 'wobbling' per se, you do not get the heat build up you get with normal 'full contact', from top to bottom of the slot. It does take longer to spark out, but, you almost never get those burn marks sometimes seen with side wheeling, and I find in MY OWN experience, I see less wall taper, top to bottom. I generally decide on the method employed, by the tolerance and finish requirements. Good luck
regards,
Chris

I would dress both sides of your wheel straight. Then I like to recess the wheel a bit, give it some relief. so when you are grinding on the side of the wheel say you are only using about .250 area of the wheel. This makes things go much easier.

Then of course dress the bottom of the wheel and if you need a very tight radius you can just dress the bottom a couple times to keep the edge sharp.

Side grinding pulls A LOT of motor load. This is why I like to relieve the side of the wheel.

Tdmidget-most Tool and Die/Gage makers know that trick. We do a lot of side wheeling. Sometimes very narrow slots. If the wheel wobbles there is less heat buildup and the wheel does not glaze so easy because the smaller contact area breaks down faster and new sharp cutting edges are being exposed. You will at least double your grinding time between redressing and in many cases it is the only way to hold a tight tolerance by keeping a straight edge on the side of the slot because the wheel is not bending after glazing. It also helps to keep the cutting rim around the edge of the wheel very narrow. Try it!

Usually you won't glaze a wheel after you get the scale from heat treat off. I sand blast it off first anyways. The wheel can still glaze if you aren't watching. Not a big deal, you just have to dress the wheel when it glazes. Its a simple 10 second deal to dress the wheel. I guess I don't dress my wheel like anyone. I dress the bottom normally, and each side I dress at something I might guess to a 2 degree inward angle, so there is no flat left on the wheel, just a sharp point.

As far as how to grind the keyway, I always take the depth in first. If i need to take .005, I'll take .004 right next (brushing) the side. Next I'll take the side in real close. Then I'll wheel up and go over to the other side and do the same, then cross feed back to where I started. Then dress the wheel and take it to size.

My digital has 0001 readout. The B&S I use at work has a fine adjust worm drive that can be engaged for tenths.
On mine at home I have about a 8" handwheel only.
I had relieved both sides of the wheel and left about 1/8 flat on the edge.

Not so much the tolerances were tight but the slots are on a round part 180 deg apart and both slots should be in the same plane relative to one end. It was held in a grinding vice. Bottoms were all clearance.

Thanks for the responses, I'll try loosening the wheel nut next time.

Dave

cash said:

I would dress both sides of your wheel straight. Then I like to recess the wheel a bit, give it some relief. so when you are grinding on the side of the wheel say you are only using about .250 area of the wheel. This makes things go much easier.

Then of course dress the bottom of the wheel and if you need a very tight radius you can just dress the bottom a couple times to keep the edge sharp.

Side grinding pulls A LOT of motor load. This is why I like to relieve the side of the wheel.

Click to expand...

Exactly... And good to hand feed the stopped wheel to lightly rub the part sides to know where you will hit when grinding as the wheel side is the weakest direction to grind and so you don't want to crash into the grind.. Make size measure to both sides just as Cash said then if a tight radius is needed dress bottom then hand feed rub about 1/8 or half way deep to mark (Note dial number) size made position.. come in to 1/8 deep .003 away.. feed just to grind witness ( or red line witness) then down feed to red line at bottom.red line to match bottom both side just for good looks.
(red line is a wax type grease marker.. you see the grease wiping away before you touch the part.)

With a very close size requirement you might side dress both sides flat with no dish just for the "take out the corner" only)the flat side makes the find position rub easy and you are not going to side grind anymore so stay .0005 away from the side. (or a whisper close)

Would not count on dial or DRO but a micrometer or measuring device to gage side location, then a .370-.373-.374-.375jo block or the like.

"Sidewheel in-feed very light in feed, get the feel for the wheel and the part material because side grinding should be light."

Light taps feed.. by the time you get close with some jo block checks you should spark count to know a thow or a half thow.

Just ball park but 46 gt for .030 radius, 60 for.020 and 80 for .010 rad..
Fine wheel don't side-grind well so some times one has to use a different wheel to get that radius.

Grinding sides of a slot.

winger said:

Most of the grinding I do is flat to size or sharp edges. So I'm not sure if I forgot or never learned this.

I have to grind some .375 wide slots about .25 deep.
These were roughed out before heat treating.

With about .010 on each side is it better to plunge the wheel or feed in from the side or combination.

I'm using a 1/2 wheel dressed to about 5/16. Bottom of slot is not critical.Both sides of the wheel are relieved about 1/8 from the bottom of the wheel.

I have a digital readout but no real fine feed on the cross. So it's light taps to adjust.

Dave

Click to expand...

Use Norton 38A100K8vbe wheel. Grind the bottom of the slot. Mark the bottom of the slot with dyekum. Dress both sides of the wheel and relieve each side just bearly short the corner of the wheel. Plunge down a maximun .0005 at a time. Touch up on the side and feed down to grind. Altought we all have ground with the side of the wheel at times, it is not recomended. The strength of the wheel is in the diameter. Grinding with the side tends to raise the heat and can burn the steel. In high carbon high chrome steel this can cause hairline microscopic cracks that can expand when the tool is placed in service and can cause failure.
Rogertoolmaker

michiganbuck said:

Exactly... And good to hand feed the stopped wheel to lightly rub the part sides to know where you will hit when grinding as the wheel side is the weakest direction to grind and so you don't want to crash into the grind.. Make size measure to both sides just as Cash said then if a tight radius is needed dress bottom then hand feed rub about 1/8 or half way deep to mark (Note dial number) size made position.. come in to 1/8 deep .003 away.. feed just to grind witness ( or red line witness) then down feed to red line at bottom.red line to match bottom both side just for good looks.
(red line is a wax type grease marker.. you see the grease wiping away before you touch the part.)

With a very close size requirement you might side dress both sides flat with no dish just for the "take out the corner" only)the flat side makes the find position rub easy and you are not going to side grind anymore so stay .0005 away from the side. (or a whisper close)

Would not count on dial or DRO but a micrometer or measuring device to gage side location, then a .370-.373-.374-.375jo block or the like.

"Sidewheel in-feed very light in feed, get the feel for the wheel and the part material because side grinding should be light."

Light taps feed.. by the time you get close with some jo block checks you should spark count to know a thow or a half thow.

Just ball park but 46 gt for .030 radius, 60 for.020 and 80 for .010 rad..
Fine wheel don't side-grind well so some times one has to use a different wheel to get that radius.

Click to expand...

The AMP mold shop here used to grind slots and depths to spec.. Then in another operation, took the part to an optical profile grinder, Louie Grinder, they called it. It had a 100 to 1 screen, where the corners were ground sharp. Years later, a friend and I wound up owning that grinder, but no use or market for it, we scrapped it. Sorry for the hijack, just brought back old memories..

Sorry to hijack the thread here, but I notice I'm the only one suggesting what I suggested (if that makes sense), see my post above. I dish out the side of the wheel by holding my stick at a slight angle (or anymore I do it with a dresser tapered at around a 2 degree angle) and I dish clear from the bottom up the side of the wheel. Note the importance of the bottom. I notice many of you are suggesting leaving .125 or .250 of the side of the wheel "flat/straight). Now, I'm not sure if flat means you have dressed it straight with a dresser or it means leaving the wheel in the purchased original condition. If the later is the case, how are you ensuring your keyway/slot has straight up and down sides? Even dressing the wheel straight I'm not sure you can get it flat up and down unless you are cutting with a point like how I dress the wheel.

I'm just looking to learn something here or maybe speed up my process. I do a lot of key grinding and its not fun and takes a lot more time than I'd like so If I'm missing something please help me out!

Thanks
Brad

For me it's dressed straight, I need all the face working.
I usually hand carve out the relief with a dressing diamond and then go in and dress the side "flat" on the machine .
Most my stuff is smaller work on 6x12s and 6x18s so the flat is about .030-.100 wide. A hundred would be huge in my world. Not so much to others.
Wall will never be straight all the way down, at some point there is a radius at the bottom unless it is undercut on a previous op.
Off the tail end of this radius there is a lead angle taking up some more room.
Sort of the same on the bottom side. Never flat into the corner but the lead is shaped differently than a face.
Since you are actually face grinding on the wall you will break down a "lead in" angle which you just dress out when it gets more than you want.
You can never grind a "zero" corner. Sometimes down to .020/.040 from the bottom is fine. Sometimes you need to get to 2-3 thou.
Something needs to use this slot. Knowing what helps.
You will never ever grind a zero-zero slot. The mating part needs a chamfer/radius to fit inside or you have to undercut the slot itself.
Bob

Bradracer18 said:

Usually Its a simple 10 second deal to dress the wheel.

Click to expand...

That's not a wheel dress, that's a pit stop!

dkmc said:

That's not a wheel dress, that's a pit stop!

Click to expand...

!0 seconds.
Do you have the stopwatch hanging on your neck here. ?
Back into a grind cycle in size? I thought I was decent but you are killing me
I can not do this. Not even close. I am at the best 10 times your number.
I have so much to learn.......
Bob

Don Bailey at Suburban Tool did a You Tube video about grinding with the side of the wheel. Check it out.

Thanks for all the info. Just built a tool to dress the side of the wheel at an angle, haven't had time to try it out yet.

Michiganbuck
I have a 100 grit as the finest wheel. At work all we have is 46 grit. The few times I had to grind a slot I dressed on down to 5/8 wide from 1". We could use a small manual grinder but most jobs are flat and occasionally to a shoulder.I figured there was a relationship between grit and radius, just never ran into the ranges before.

Dave

Don’t have my reference handy but I would choose the 46 grit for a .025 rad.. the 100 grit for .010/,012
Yes the 46 is .014 and the 100= .07 but you rarely get down to the one grit size in a corner.
Dress bottom and then grind part slot to the low limit of depth (if small limit stay .002 off). Paint with a grease pencil.
Dress wheel bottom and sides. Then dish in the two sides with a Norbide stick, silicone carbide stick, or come in with your diamond to .015 recess starting .020 above peripheral (OD) to perhaps 7/16 up. Go back in to touch red grease bottom and then grind with cross to just make low limit measurement. One side then the other. *Side grinding needs very fine in-feed and no crashing into sides so good to first come in to hand feel the touch with motor off and mark the touch target with an arrow on your note to show the in feed direction cross dial number. Don’t count on dial numbers for take off but with the actual measurement.

To take radius(with changing wheel grit if needed) with slot now made to low limit depth, width and centered for location. Dress bottom (take .005 so you will know the number where you should hit at bottom)and dress sides square, red grease sides and bottom, Hand touch feel the slot side half way up and note dial number, back away .005 and start motor with long travel going left and right cross into the .001 away number with being careful for a touch. At the - .001 cross dial number down feed as you long travel to your bottom number target watching a grease line at bottom. You may hit the radius first so then down feed to red mark… If you hit red mark the finish the radius cross feeding into the red grease on the side. Come in to just clean up some of the red not all so you don't make a hard grind and perhaps burn the side.. Your size is there so no need to take more.

Any time you grind a form good to note the dial positions so you know where you should hit and take a dress at a certain amount so you still know where you will hit after dress.
There are two kinds of grease pencils, one actual grease and one like a grease chalk.. I like the grease kind better as it begins to carry and streak a tad higher and lubricates the wheel like coolant .... good IMHO

Slots I like to measure from gage side (s) and measure width with a Jo block.

Davis In SC said:

The AMP mold shop here used to grind slots and depths to spec.. Then in another operation, took the part to an optical profile grinder, Louie Grinder, they called it. It had a 100 to 1 screen, where the corners were ground sharp. Years later, a friend and I wound up owning that grinder, but no use or market for it, we scrapped it. Sorry for the hijack, just brought back old memories..

Click to expand...

Sounds like a Wickman that the old shop used for form work.


I'd dress the wheel to width, then use a norbide stick to relieve the sides-you just cut with the corner. Wax the wheel if needed.

Hi All:
This is the kind of situation where a tilt head grinder like a Taft Peirce is a Godsend.
I have a little surface grinder that can do this, and when I need a dead nuts accurate slot I always tilt the wheel and then dress the side so I end up with line contact between the side of the workpiece and my now cone shaped wheel.
You don't need to tilt very much; a couple of degrees is all it takes.
I also don't feed with the cross slide, I downfeed into the slot to keep the contact area down as much as possible.
The grind ends up without crosshatching, size control is super easy, and re-dressing the wheel is too.

Of course, tilt head surface grinders are pretty rare; I know only the Taft Peirce, but there are probably others.
All the rest of you will have to suffer with conventional side wheeling...you have my sympathy!!
Cheers

Marcus
Implant Mechanix
Vancouver Wire EDM -- Wire EDM Machining
Clarus Microtech