# Toolpost Grinder uses



## danleereed (Aug 19, 2014)

I was wondering what you guys use your tool post grinders for on your lathe. I am looking at one for grinding my chuck jaws. I am sure there has to be more that it is useful for. I would feel better about the investment if I knew what all I could do with it. Thanks for the look, I hope to see a lot of good ideas.

Dan Reed


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## rdean (Aug 19, 2014)

Yes I am also interested.

Ray


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## chips&more (Aug 19, 2014)

I have a Themac, Dumore and a Dremel for metal lathe use. Each one has a specific capability. And each on has been used in my shop through the years. The Themac and Dumore are expensive even used and maybe not justifiable in the home shop. But if you need to grind something that can’t be tooled, well then it’s decision time and maybe no telling the wifey poo. I don’t like to grind stuff in my metal lathe because of the nasty swarf it generates but then I do not have a dedicated grinder for the tasks so I just carefully cover up the lathe before I grind. I made a lathe holder for the Dremel and for the piece of junk that it is, it does a surprisingly decedent job. Maybe the finish isn’t a mirror finish but good enough for a lot of projects…Good Luck.


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## f350ca (Aug 19, 2014)

I think the biggest advantage of one is cutting hard material, just not much of it. They won't turn your lathe into a cylindrical grinder, your still dealing with the precision of your spindle but they will get you to a tenth of a thou. 
And they give a beautiful finish. Here I'm resurfacing the neglected tapper of a collet chuck for a Colchester lathe. I mounted the stock in the three jaw, machined it to 1 inch then grabbed the stub with a collet.






Came out with 2 tenths of a thou runout.

Greg


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## GarageGuy (Aug 19, 2014)

They're good for dressing worn or damaged dead centers.  Here is Tubalcain's YouTube video on how to do it:

http://youtu.be/IHNLSnFSKrM

GG


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## darkzero (Aug 19, 2014)

I bought a air pencil die grinder from HF that I wanted to use for grinding the jaws on some micro chucks. http://www.harborfreight.com/18-air-micro-die-grinder-69745.html  I also thought about using this one too. http://www.harborfreight.com/electric-die-grinder-with-long-shaft-44141.html

Figured it would be fine for what I wanted to do. I tried using a dremel to grind something else but it didn't do a very good job. Just as I was about to start making the tool post mount for that pencil grinder I scored a Dumore tool post grinder locally for $150 just last week. It's their smallest model #14 but I'm so glad I got it.


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## danleereed (Aug 19, 2014)

chips&more said:


> I have a Themac, Dumore and a Dremel for metal lathe use. Each one has a specific capability. And each on has been used in my shop through the years. The Themac and Dumore are expensive even used and maybe not justifiable in the home shop. But if you need to grind something that can’t be tooled, well then it’s decision time and maybe no telling the wifey poo. I don’t like to grind stuff in my metal lathe because of the nasty swarf it generates but then I do not have a dedicated grinder for the tasks so I just carefully cover up the lathe before I grind. I made a lathe holder for the Dremel and for the piece of junk that it is, it does a surprisingly decedent job. Maybe the finish isn’t a mirror finish but good enough for a lot of projects…Good Luck.



I found a nice one, off brand on ebay. Bidding on it tomorrow. Has a 10 inch ID bar and standard bar. If I don't get it, I'll keep looking for a good deal on a nice one.



GarageGuy said:


> They're good for dressing worn or damaged dead centers.  Here is Tubalcain's YouTube video on how to do it:
> 
> http://youtu.be/IHNLSnFSKrM
> 
> GG



I have been watching a lot of his videos. Great stuff and thanks for the link.



darkzero said:


> I bought a air pencil die grinder from HF that I wanted to use for grinding the jaws on some micro chucks. http://www.harborfreight.com/18-air-micro-die-grinder-69745.html  I also thought about using this one too. http://www.harborfreight.com/electric-die-grinder-with-long-shaft-44141.html
> 
> Figured it would be fine for what I wanted to do. I tried using a dremel to grind something else but it didn't do a very good job. Just as I was about to start making the tool post mount for that pencil grinder I scored a Dumore tool post grinder locally for $150 just last week. It's their smallest model #14 but I'm so glad I got it.



I was considering the second links option earlier today. It would probably do good with a nice mount. I don't really know what I would grind other than my chuck jaws. I have .005" run out at the chuck,.015 to .020 @ 10" Its brand new Shars 10" 3 jaw. Cheap though. Maybe I'm being to picky. 

Earlier today I was trying to face and center drill some shafts about 2' long x 2.5"diameter. I had the steady rest about 5" from the end because of an already existing keyway. To get the shaft on center it was very hard to turn the pin adjustments on the rest. I was afraid I would get to much pressure against the rest pins and do some damage at 400 rpm. I don't have any experience with the steady rest to make a good judgment. Now that I think about it, I'm going to check that shaft for straightness. I don't know why I didn't think of that earlier. But what do you guys think about .005" at the chuck? I have ran a lathe or 2 before but they were all cherries, everything must have been perfect on them. Plus, I am using an old used machine that was in poor shape when I received it. Been fixing and tuning since I got it. I may have missed something. I have been researching tailstock alignment, and test bars.


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## darkzero (Aug 20, 2014)

.005" would drive me crazy. .002"-.003" is typical for an import 3 jaw but there are ways to possibly get it lower without grinding. Is a direct mount chuck or mounted on a back plate? Spindle mount type? If there is a backplate was it purchased or self made & did you true it up to your spindle?


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## Skarven (Aug 20, 2014)

I used a 'toolpost grinder' setup to fix the starter gear teeth on the generator of my Yamaha Virago 750.  
The teeth were worn so much that the starter would engage about 1 out of 20 times.
The bearing in the grinder (Chinese junk!), was so bad that I had to use what I would call a statistical approach - 
feed 2 thou and then wait for about 5 minutes till there were very few sparks.
It took a lot of time but it saved me about  $1200.  Still works, 3 years later!
Sometime I will buy a real grinder.

Kai


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## ericc (Aug 20, 2014)

Looks neat!  Were you just grinding the OD of the gear?


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## Skarven (Aug 20, 2014)

No, the grinding was on the side of the teeth.  In the first picture you can see they are worn and rounded off.
The grinding made the sides flat.  I had to make the small relief flat that you can see in the last picture with
a chain saw file. (The flat file)

I first tried to turn it in the late, but the tool lifetime for both HSS and carbide could be measured in milliseconds!


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## hman (Aug 20, 2014)

Skarven said:


> The bearing in the grinder (Chinese junk!), was so bad that I had to use what I would call a statistical approach - feed 2 thou and then wait for about 5 minutes till there were very few sparks.



Love it!!!!:rofl:

... and congratulations on figuring out how to overcome the shortcomings of your tools.  Mind over matter!


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## labparamour (Aug 20, 2014)

I tried what's been mentioned above- die grinder held in tool post using angle iron with flat bar tab welded at apex.
Have 5" 3-jaw chuck that is bell-mouthed. This worked pretty well: light cuts with many passes. Challenge was not being able to load jaws by closing in but by opening against ring.
really enjoy this forum…and Mr Pete!
Darryl


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## GarageGuy (Aug 20, 2014)

Light cuts with many passes is pretty much the standard operating procedure for most tool post grinders... home made or not.

GG


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## george wilson (Aug 20, 2014)

Years ago,when I had no tool and cutter grinder,and only a small horizontal mill(Burke #4),I would chuck up a piece of steel and turn it to fit the bores of horizontal milling cutters. Even the spiral slab mills. Then,I rigged up a tooth to rest the teeth on,which traveled with the carriage. I used a little Dumore Tom Thumb tool post grinder to effectively sharpen those milling cutters. It worked quite well. Minor smoothing with an India stone,and the cutter was good as new.


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## PGB1 (Aug 23, 2014)

I'm by no means an expert on machine tool use, but I have a couple of suggestions for using a tool post grinder on the lathe (If you all don't mind an amateur's input)

I know grinding on the lathe can be damaging if things are not protected, so here's what I do. It may be overkill, but why risk it?

Step One-
To protect the ways, I wipe them down if they are not already clean, then re-coat them with fresh way oil. It seems to be thick enough that any dust from the grinding stone that escapes Step Two (below) will be suspended in the oil. But, this is just my observation. Another, perhaps better product, would be Hyper-Lube from the auto parts store. it is really thick & sticky. Cleanup is tedious, however. Naphtha seems to work well after using sacrifice paper towels (or in my cheap-skate case; newspaper) to wipe it al down.

Protection Plan Step Two is to wrap the oiled ways with food service cling wrap. It is like a thick "Saran Warp" and comes in wide rolls. The sheet has some tackinesss to it when stretched.  I just go 'round-n-round', circling the ways & chip tray, pulling tight.  The stone grit seems to stick well to it. Any dust that escapes gets trapped in the oil on the ways. My roll is 20" wide. Restaurant suppliers and some shipping suppliers sell it. (Uline com 'Stretch Wrap")

The Tool-
I use a Dumore flex shaft grinder that I got at a garage sale. Sometimes I'll use a Dremel tool also, but it's shaft doesn't run very true. Of course, with either, there is not a great deal of precision. 

The handpiece gets held in a homemade tool post mount. I stuck some pictures in this post.
One day, I'll find a tool post grinder begging to come home with me.

Like Tubalcain said in the video that Garage Guy linked, wear a face shield. Flying stones are evil.

Have Fun & Enjoy This Day!
Paul


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## Skarven (Aug 23, 2014)

Covering the ways is probably a good idea, but be careful though.
I tried to cover the ways with normal 80g printer paper.

After half an hour of grinding, there was a small pile of iron dust under the grinder.
And suddenly the paper under it ignited!!!!  I think maybe the oxidation of the dust created the heat.

Luckily, this happened when I was looking.
Maybe Aluminum foil would be better?

Kai


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## george wilson (Aug 24, 2014)

Heavy plastic trash bag works. Do not use cloth to cover the ways. The fine dust will go right through it. Carefully and slowly fold the plastic in on itself when removing. Dispose of it. Don't try to save it. Wipe down the lathe at once without moving the carriage.

I also stuff the openings in the chuck with tissue paper before grinding. You don't want the dust getting into your chuck either. If it does,the internal parts will lap each other every time you move the jaws.

Using any kind of diamond wheels is strictly OUT!!!!! They are forever if they get into your machine's sliding parts.


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