# Modifying an ancient Sioux valve grinding machine.



## DICKEYBIRD (May 25, 2008)

I mentioned in another post here that a friend gave me this old Sioux #621 valve refacer. My plan was to lightly refurbish it and use it to reface the odd engine valve and modify it for a little tool grinding.







I wanted to make a few accurately ground pointed shafts from drill rod in various sizes. They will be used to accurately locate pop marks for hole drilling without having to change the collet in the mill...ie: need 1/4" hole? Fit 1/4" collet, locate pop mark with pointy 1/4" drill rod, lock the table, install drill bit and go. It should save a little bit of time and will be accurate as I'll need.

When I chucked up the 1st piece of drill rod, I checked the runout and found .0045". YUCK! I took the chuck apart, cleaned, lubed and reassembled it with the rollers in different relative positions but the best I could get was .004". Goodbye old worn chuck!






I checked the runout of the spindle itself without the chuck and it was almost perfect. I removed it and sawed off the chuck nose just outside of the threaded section. It then went into the 4-jaw and dialed in 'til it showed no runout. Fortunately, the chuck portion wasn't super hard and I was able to turn the threaded area down with a carbide insert to leave a nice, smooth surface to fit an adaptor for a replacement chuck. The spindle itself is VERY hard; a file just skids on it. It runs in cast iron with oil grooves and oil cups placed for easy lubing. The system must work because the 50 yr. old shaft shows only light polish marks with little measurable wear.






I ordered in an inexpensive 3" 4-jaw chuck from Little Machine Shop and was well pleased with it. http://www.littlemachineshop.com/products/product_view.php?ProductID=1175&category=566826475 I sketched up an adaptor in TurboCAD using the dimensions on LMS's website. I printed it out and glued it to a chunk of 1/2" aluminum plate. The blank was clamped in the mill and the 4 mounting holes spotted and drilled. It was then rough-cut to a lumpy round shape on the bandsaw and bolted to the back of the chuck. The chuck jaws were removed and the little feller was chucked & dialed into the bigger 4-jaw on the lathe. The adaptor o.d. was turned to size and the i.d. drilled & bored carefully for a push fit onto the spindle. The adaptor was then drilled/tapped 10-24 for the clamp screw and a slot was cut with a slitting saw.






It fit perfectly and has minimal runout. Of course, any runout of the work can now be dialed out easily in the little 4-jaw.






Can't wait to get the new belts in so I can pour in some coolant and begin using it. I think I can also use the 4 jaw to finish grind model engine crankpins and eccentrics. I hope so anyway.


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## PTsideshow (May 26, 2008)

Very nice ;D


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## baldrocker (Sep 14, 2008)

I dont have a valve grinder but I love learning
a new way (for me) to mount a chuck to a spindle
This is what makes this site the best
BR


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## DICKEYBIRD (Sep 19, 2008)

Hi there B/R. Sorry, I'm not really a rude, impolite person and usually respond right away to posts in my threads. I just plain missed your response for a few days.

That was the only way I could figger out how to mount the chuck and it worked surprisingly well. I'm glad you brought that post back up to the top because those pictures reminded me I need to get back to working on that neat ol' machine. The wheel turned out to be too coarse for my tastes so I need to look around for another.


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## MadKad (Sep 20, 2008)

That is [email protected] clever way to mount it, I really wouldnt have thought that would work as the clamp plate is bolted to the chuck, so I wouldnt have thought it would clamp due to the bolts through the plate, if you get what i meen.

Does it close that clam gap up much?

also does it stay on in center?


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## DICKEYBIRD (Sep 20, 2008)

M/K I bored the adapter center hole as precisely as possible. Matter of fact, I stopped at a thou too small. It sprung open a bit when I cut the slot.

I mentioned in the 1st post that the adapter OD & ID was turned with it bolted to the back of the chuck and the chuck chucked (like that sentence structure? ;D ) in the lathe. I removed the adapter & cut the slot. I then clamped the adapter onto the spindle and it's runout was very close to perfect. There is a little slack in the adapter to chuck mount boltholes and I was able to fiddle about bumping the chuck with a lead mallet while checking the runout with a DTI and torquing the mount bolts. 

The chuck OD now measures less than a thou runout and of course the work is further dialed in with the 4-jaw. I probably wouldn't have done it this way with a 3-jaw at 1st thought but it actually came out so close I would do now. If I had it do over, I'd scrounge a piece of mild steel instead of aluminum to eliminate the worry about the difference in expansion rates. So far though, it shows no signs of loosening in use. If it does, I suppose I could mount it with a little blue Loctite.


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