# Pressing A Bench Grinder Spindle Back To Spec



## Ozwelder (May 3, 2015)

I have a  8" 1 HP bench grinder that had something fall on it when in storage.As a result the spindle suffered a bend about where it exits the case. Dial indicator says .012" run out.

It was a Taiwanese bench grinder but good quality for its day as it is about 30 years old  and before its accident was good performer and would run on for a couple of minutes after switch off.

I can disassemble to the stage where I can put the spindle with attached rotor under a hydraulic press in vee blocks.
Is the best way to straighten the shaft or is another way recommended?

Thank you

 Ozwelder


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## kd4gij (May 3, 2015)

You got it. That is the way I would do it.


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## The Liberal Arts Garage (May 3, 2015)

.012 inch is about the maximum I would straighten as above. Even here,  I would 
check the point of bend with a drop of dye and a good magnifying glass....BLJHB


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## barnett (May 3, 2015)

I would check the point of bend with a drop of dye and a good magnifying glass....BLJHB[/QUOTE said:
			
		

> Ok, maybe a noob question, but why the dye ?


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## The Liberal Arts Garage (May 3, 2015)

If a stress crack is starting ( very dangerous! ) the dye will seep into
the crack and make it more visible.......BLJHB


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## Ozwelder (May 3, 2015)

The Liberal Arts Garage said:


> .012 inch is about the maximum I would straighten as above. Even here,  I would
> check the point of bend with a drop of dye and a good magnifying glass....BLJHB



Ah hah!  potential cracking ! Something I should have thought about! I am fortunate to have once worked in NDT and have access to some die check and developer.

Many thanks for the replies.


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## BigWeld (May 3, 2015)

Is it possible to machine out the 0.012" and fit the stone/wheel on that side with a slightly bigger spacer?


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## FOMOGO (May 3, 2015)

The press should work fine. The 5 hp 3ph motor that came with the rpc I have for my mill had a bent shaft. I was able to get it almost perfect with out much effort. Mike


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## The Liberal Arts Garage (May 4, 2015)

BigWeld said:


> Is it possible to machine out the 0.012" and fit the stone/wheel on that side with a slightly bigger spacer?


Trim to "straight"shrink on a thin sleeve ( wheel andwashers length,true up threads)
Get experienced help on site....... BLJHB


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## Tony Wells (May 4, 2015)

I wouldn't even tear it down. Mount it securely, find a long enough piece of close fitting tubing and bend it by hand. It's already in the bearings it will run in, so better than vee blocks. Should be able to get it plenty close.


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## Lamar (May 5, 2015)

Ozwelder said:


> I have a  8" 1 HP bench grinder that had something fall on it when in storage.As a result the spindle suffered a bend about where it exits the case. Dial indicator says .012" run out.
> 
> It was a Taiwanese bench grinder but good quality for its day as it is about 30 years old  and before its accident was good performer and would run on for a couple of minutes after switch off.
> 
> ...


There is a place in Cleveland, Tn called Flame Hardening that specializes in straightening shafts of all kinds did some work for me very reasonable


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## Ozwelder (May 6, 2015)

Lamar said:


> There is a place in Cleveland, Tn called Flame Hardening that specializes in straightening shafts of all kinds did some work for me very reasonable


Thanks Lamar,
I am in Australia the shipping might be a trifle expensive.


Tony Wells said:


> I wouldn't even tear it down. Mount it securely, find a long enough piece of close fitting tubing and bend it by hand. It's already in the bearings it will run in, so better than vee blocks. Should be able to get it plenty close.



I believe I shall have a go at this method. 
Thanks for your replies gents,
Grahame


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## intjonmiller (May 5, 2016)

I just discovered this same issue with my own. I had two, gave the nicer one (older Buffalo) to my brother because he didn't have one for his shop. Now I finally get around to mounting a grinding wheel on the remaining one (a Harbor Freight special I had only ever used for buffing, and hadn't used at all in a solid decade) and discover that the shaft is bent on the left side. Minimal vibration when I mount a wheel on the right, but terrible if I put one on the left. I haven't measured how bad it is yet, just trying to figure out how to approach the problem. Thanks to everyone for already having information for me to find.


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## The Liberal Arts Garage (May 5, 2016)

I discussed this problem (with others adding more good thoughts) some time ago
See if you can call back that thread......BLJHB


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