# Quick and Dirty Toolpost Grinder



## Micke S (Dec 20, 2014)

I made a toolpost grinder today from scrap parts and a new air grinder. The front of the grinder is metal and it has ball bearings. I made an expandable clamp and some other stuff to make it fit on the QCTP. Just to wire brush it and spray matt black paint and it may look OK ) The important thing is stability, which is there.






	

		
			
		

		
	
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## CoopVA (Dec 20, 2014)

Well done!  I like that!


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## Micke S (Dec 20, 2014)

Thank you !

I've now sand blasted, primed and painted the piece for a more uniform look. 

Tomorrow it will be tested to grind jaws in a 3-jaws chuck. I'll weld a bolt on each jaw tip. Then let the jaws press via bolts on a bearing outer ring and grind the jaws inside. The bolts will then be removed and the jaw tips turned and grinded to remove any trace. I hope it will work...


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## thomas s (Dec 20, 2014)

Oh I don't think I would call that quick and dirty. It looks great.

 	 		 			:thumbzup3:


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## Micke S (Dec 20, 2014)

I didn't have to do much. I've just made the expander bushing, and cut a solid bar for the toolpost and weld it to an existing clamp. It took about two hours.
Scrap parts can be very rewarding by sometimes being possible to modify for personal needs.


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## Micke S (Dec 21, 2014)

The air grinder works very well for reconditioning chuck jaws and the grip surfaces now looks like new. I drilled a 5 mm wide 25 mm deep hole in the tip of each jaw. They were placed against a stop in the drill press machine vice to be drilled the same. Then I put a 5 mm locking pin in each hole and let the jaws press them against an outer ring of a ball bearing. 

The runout, measured with a 2" rod 2" from the jaws is only 0,002 mm, i.e. 0,00008 inch. This is repeatable short term *as long as the same screw is used*. It will of course change over time since it is a 3 jaws scroll chuck but it became usable now. The purpose was however more to test the principle since I have other chucks in good condition.

Other observations that came with the precision grinding exercise is e.g. that it is necessary to lock the cross feed. 




The correction of bell mouthed is seen by the grip width changes slightly over the length.


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## Rick Leslie (Dec 21, 2014)

Maybe 'quick' but definitely not 'dirty'. And the proof is in the grinding. Looks like it performed well. I also hadn't thought of putting strain screws in the jaw tips to preload the jaws. 

IDK how durable the paint will prove, but you might want to look into a home black oxide kit like Caswell. http://www.caswellplating.com/metal-finishing-solutions/black-oxide-kits.html


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## Micke S (Dec 21, 2014)

Thank you for the hint, the paint I used is not durable at all and it would be great to try something better like the one you propose.

https://www.youtube.com/watch?v=jj3TApAETHw&feature=youtu.be


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