# Another Cutter Grinder



## Hawkeye (Feb 26, 2014)

Some years ago, I started to build a tool and cutter grinder, mostly  with a view to sharpening endmills. I needed to make a rotary table to  mill a curved slot, so I set the grinder project aside. I finished the  RT, but never got back to the grinder. This is as far as I got. That's  an R8 spindle, since I have a full set of R8 collets.


 

Today, I had a day off so I decided to make the grinder spindle. I  figured an MT2 socket would be the most versatile in order to mount  whatever I may need to spin as the project grows. I roughed the taper at  around 1 1/2*, to be trued up with a tapered reamer.


 

It took quite a while to ream out the MT2 socket, but it came out quite nice.


 

I got to try out my new swing-up threading tool to cut the pre-loading thread.


 

The finished spindle. Next step is the body that the bearings mount in.


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## Bill Gruby (Feb 26, 2014)

It's about time you started this one again. Been waiting since I started mine. :rofl::rofl: Keep up the good work.

 "Billy G"


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## melsdad (Feb 26, 2014)

Now with another thread on a cutter grinder build. The temptation to build one of these may be more than I can handle.

I am looking forward to this as well....subscribed!!


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## Bill Gruby (Feb 26, 2014)

Brian;

 Mike is an extremely gifted machinist. His work is impeccable. This will be a great build.

 "Billy G"


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## chuckorlando (Feb 26, 2014)

Awesome. I was showing some friends Bills thread. It's cool making parts and all. But when they see them parts go together to make a real live tool or machine, thats pretty dang impressive.

Then show them what a good one cost to buy, game over. ahahaha

I look forward to this thread and nice work so far.


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## Hawkeye (Feb 26, 2014)

Thanks, guys. Bill's giving me way too much credit. I'm glad this isn't a competition. ) 

Since I left the spindle in the lathe for the whole operation, I couldn't test fit the bearings. They ended up just a bit too 'slip fit'. I'll probably apply a light knurl to the bearing areas to plump them up.


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## melsdad (Feb 27, 2014)

Mike you can try a red or pink loctite to fill the void if it is not excessive. 

sent from my hand held hickymajig


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## hvontres (Feb 28, 2014)

melsdad said:


> Mike you can try a red or pink loctite to fill the void if it is not excessive.
> 
> sent from my hand held hickymajig



Actually, for holding bearings on shafts you might want to try the green 609 (http://www.loctite.com.au/cps/rde/x...redDotUID=productfinder&redDotUID=10000009REW). It will work with light press fits and cover up to a 0.005" Gap.


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## melsdad (Feb 28, 2014)

I only mentioned the others for thoughts of removal later. The green has quite a grip

sent from my hand held hickymajig


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## Bill Gruby (Feb 28, 2014)

The grip comes from it's gap filling ability. It removes with light heating.

 "Billy G"


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## Hawkeye (Feb 28, 2014)

I did think of using Locktite, but there may be a slight chance of it setting up with the spindle a thou or two off centre. I suppose I could turn it with the spindle vertical while it cures. The viscosity of the liquid might work to centre the shaft.


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## Hawkeye (Mar 9, 2014)

I spent some time today making the bearing carrier for the spindle. I  really need to get some more tapered-shank drill bits. They are the best  way to drill large holes on the lathe.


 

The usual boring work to make the through-hole and the two pockets for  the bearings. I managed to sneak up on the pocket diameters for a press  fit on both bearings.


 

The fit was tight enough that the arbor press wouldn't quite do it, but the hydraulic press had no trouble at all.


 

I figured I'd better check the runout, so I set it up as shown.  Unfortunately, there is about 0.006" TIR. I'll see what I can do to  improve that. It's possible that the economy bearings have some runout.


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## Bill Gruby (Mar 9, 2014)

Mike;

  If you used the economy bearing the TIR could be coming from the tight press fit. Tight fitting bearings in that category will distort some.

 "Billy G"


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## DMS (Mar 9, 2014)

Do you have any provision for pre-loading the bearings Hawkeye? If not, that could be part of the issue, as those look like deep groove ball bearings. Without a preload they will precess within the outer ring.

If you already have the bearings preloaded, then another tip I picked up is to cut the final spindle taper with the spindle assembled. When I did it on the small grinding spindle I made a while back I mounted the spindle body in my steady rest, and grab the drive end of the spindle in my chuck. This is quite effective, but it relies on the bearings not moving, so if you ever disassemble, you will need to re-cut the taper again.


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## Hawkeye (Mar 9, 2014)

DMS, I do have a preload nut at the pulley end of the spindle. It's an interference fit, so it will stay put when it's adjusted.

When I was looking at it this morning, I was visualizing exactly what you suggest. Good to have confirmation. The steady is quite robust, but the through-hole is only 2 1/2". Good thing the spindle body is 2 3/8".


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## Bill Gruby (Mar 9, 2014)

Check the run out in the same manner only use a Granite Plate if you have one. I'll bet it's less than you see. I used tapered roller bearings and everything was fine.

 "Billy G"


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## Hawkeye (Mar 9, 2014)

Bummer! I mounted the pulley end of the spindle in the MT3 collet on the  lathe, then tried to slide the steady onto the bearing carrier.


 

The through-hole is not centred on the lathe spindle.

Plan B. I clamped the carrier to the compound, with appropriate shims.  That held it solidly while I touched up the MT2 socket with the tapered  reamer.


 

Still reading 0.005" TIR in the test setup, but a ground centre in the  socket measures 0.003". It's important to note that this spindle is for  the grinding wheel, not for the toolholder. If it's off a couple of  thou, it will still work, more like a flycutter. The cup wheel can be  trued up, but would have to be repeated each time the wheel is  remounted.


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## DMS (Mar 9, 2014)

True, once you dress the stone that runout should be invisible. I doubt you will be swapping wheels frequently, so it shouldn't be much of an issue.


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## Bill Gruby (Mar 10, 2014)

I agree that after dressing the run out will be all but gone but what about any vibration left? Won't that hurt the finish? The wheel will be true but the shaft will still be out. Just thinking out of the box. Just how fast will that spindle be turning? Mine will max out at 5100 RPM with the low end at 3400 RPM. Any vibration at those speeds won't be fun.

 "Billy G"


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## Hawkeye (Mar 10, 2014)

I am planning on building a balancing system into the mount. It worked wonders with my 8" pedestal grinder.


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## chuckorlando (Mar 10, 2014)

All kinda good info going on in here. Looks good.  You would not happen to have any more pics of how you set it up in the lathe would you?


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## Bill Gruby (Mar 10, 2014)

Hawkeye said:


> I am planning on building a balancing system into the mount. It worked wonders with my 8" pedestal grinder.



 That should work fine Mike. I am nearing the end of my build.

 "Billy G"


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## Hawkeye (Mar 11, 2014)

Chuck, those are all the pictures I have of that setup. In the second one, you can just see the end of the lathe spindle. The grinder spindle pulley end is 5/8". It is in an MT3 collet in the lathe. The actual cutting was done by an MT2 tapered reamer. Just a skim cut to try to even out the runout.


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