# Toolpost Grinder For Sb9a



## ogberi (Jun 25, 2015)

Hi All, 

When I purchased my lathe, it came with a Union Manufacturing 6" 3 jaw chuck.  This chuck uses two piece jaws, but no jaws were to be found in the shop where I purchased it from.  I did find replacement jaws from Shars, but their QC must be asleep on the job.  There is one problem child jaw that throws about .006" runout to the workpiece being chucked.  The runout follows that jaw, so I know it's the wonky one.  I need to grind my chuck jaws.  

Since my knockoff Dremel isn't well suited for this, and because my hobby funds are flat broke, I decided to see what I could cobble together from the scrap bins.  I laid my raw materials out, stared at them for a bit, then tossed a few ideas into the back of my head and let them stew.   The next evening, I doodled a few lines in my project notebook and got started.  

The spindle is 3/4" CRS, about 5" long.  I have a suitable piece of steel bar to make the housing from.  Bearings and motors I have in plenty, so no problem there.   I decided to copy the spindle of my RotoZip, because I have collets and an extra collet nut for it on-hand.  It can take up to 1/4" shanked tools, so it'll be useful. I've had no issues with runout on the rotozip.  

I started by cutting a piece of 3/4" CRS about 5" long.  Grabbed it in the 4 jaw, indicated it, then faced and center drilled it.  Flip the workpiece and repeat.  

Off with the 4 jaw, on with the dog drive plate.  Installed the dead and live centers, slapped a dog on the workpiece, and got it mounted.  



I hogged off most of the material with a tangential tool, and got close to the desired diameter for the spindle shank.  Ran out of time, and the workpiece needed to cool anyway.  



More to follow as the project progresses.


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## ogberi (Jul 2, 2015)

Been doing some more work on this project.   The spindle is finished, threaded 1/2x28 for the Rotozip collet nut, bored for the collet, and the bearings are a 'little bit of hand effort' slip fit on the shaft.  





I worked on the housing.  Got a handful of these cylinders from a friend, and aside from the fact that they're hard as heck, they cut nicely with a really sharp HSS tool.  It's actually easier to face off 1/4" than to cut it off with a sawzall.  

Grabbed it in the 4 jaw, dialed it in reasonably straight.   I knew the entire diameter would be reduced, so I didn't chase zeroes on the DI.  



I love my tangential tool.  Easy to sharpen, cuts facing and turning without moving it, and it can flat hog off some material.  Even on this stuff.  If it gets dull, it takes no time at all to re-sharpen, and it's easy to set on center. 




A quick hit with some sandpaper, and it shines right up.  




The bore came out nicely.  I'll have to heat this in the oven for a bit so I can press in the bearings.  Getting them out would promise to be a pain, though.  

I still have to turn the end that's currently in the chuck, face it, and bore for the rear bearing.   I decided to use two bearings in the front with a thin spacer between, just because I can.  I figure two bearings can take a beating better than one bearing, and it supports more of the spindle shaft than a single bearing.    It's been nice to get into the shop and concentrate on just making chips.


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## Bill Gruby (Jul 3, 2015)

Way to go! I'll be watching this one closely. Great start.

 "Billy G"


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## ogberi (Jul 5, 2015)

Made some soft jaw pads for the 4 jaw chuck.  Simply cut some 1" copper pipe pieces about 1 1/4" long, slit them lengthwise, and spread them open just enough to fit over the jaws on the chuck.  Reversed the workpiece, dialed it in with a DTI and spent the time chasing the zeroes on this one.  

Got the rest of the housing turned, and faced it to length.   Now I'm waiting for it to cool before I bore the recess for the rear bearing.   

Once the bearing recess is done, I'll move to the horizontal mill.  My plan is to cut two areas away above and below the centerline, along the axis of the spindle, so as to leave a 'tab' sticking out which can be grabbed in a toolholder for the QCTP.  I'm still contemplating what motor to use, and how to mount it.  

But one thing leaves me at a loss.    The Atlas horizontal mill has V grooves that run the length of the table for clamping round stock.  However, I'd rather not mar up the finish of the part too badly on the cast iron table.  I can use copper pads underneath the clamps, but I'm not sure how to pad the V groove in the table.  Should I use a piece of soda can (aluminum) between the table and the stock?  Would that still let it register good in the groove, but protect the finish?  I've got a decent amount of time into this workpiece, so I'd really rather not mess it up.  And after cutting away the metal to form the tab, trying to polish it in the lathe won't really be a smart thing to go.  

Pics to come this evening.


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## ogberi (Jul 5, 2015)

Work was paused on account of lightning.  I don't relish the idea of being in a big tin can with lightning hitting all around.  Nope.   After the weather calmed down, I wandered back out to the shop and kept on working.
	

		
			
		

		
	




Housing turned to length, and the rear bearing bore is done.  



The setup to mill this.  The vertical mill is great for this work, but the angles make it hard to see what you're doing.  I found the top of the workpiece, and used an indicator to set the height and my noga-knockoff to watch the depth as I made repeated passes.   The tab ended up being just enough for a QCTP holder to grab securely.  





The tab is done, and the part cleaned up.     Tomorrow if I have time I'll figure how to mount a motor on it, and do any last machining that has to be done. 




CHIPS! 











More to come.


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## ebgb68 (Jul 8, 2015)

Nice work !!


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## Andre (Jul 12, 2015)

Very nice work!


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## chips&more (Jul 12, 2015)

Looking good!


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## springer (Jul 16, 2015)

very nice work.  anxious to see how you mount the motor on there.  on a side note, i also love my tangential tool holder, you can really hog some material off.  that thing does 90% of my turning.


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## ogberi (Jul 17, 2015)

I'm in the process of making a new spindle, longer so I have more reach and more options for mounting a motor and pulley on it.  Taking video of it, and will post a link to it once I have it ready.
Also going to make an arbor so I can utilise my 3" grinding wheels.  It's an interesting project, and easier than I thought it would be.

Love the tangential tool.  It's my go-to tool for turning and facing.  Only 1 angle to grind, so touchups are literally about 2 minutes, and that's from taking the toolholder off the qctp, to making another cut.

The vertical shear tool is another go-to tool.  Again, easy to sharpen, superb surface finish even on 1018 crs.  Slow, and not for hogging, but leaves a buttery smooth surface.

Stay tuned, should have lots of shop time this weekend.


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## ogberi (Jul 20, 2015)

Made a new, longer spindle.  Spent a lot of time chasing zeroes, and got the tailstock of the lathe adjusted to OCD level accuracy.  The DTI got a workout on this part.  I have some video, but my camcorder delights in loosing its tiny mind at random.  I have to edit it all together.  
Still to be made is an arbor for the 3" wheels, but I have to grind an internal threading tool for that.  The portion behind the collet nut is unfinished because I want to turn it down at the same time as the arbor.   All of the threading was single-point threaded on the lathe, with the workpiece between centers.  3/8x24 for the retaining nut that goes on the right hand side, 1/2x28 for the rotozip collet nut.  

Still on the todo list is the arbor, two pulleys, and a mount for the motor.  

Here's where it's at so far.


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## ogberi (Jul 26, 2015)

Absolutely no progress lately.  I've been busy with family issues. 

I was curious about the runout of my home-made toolpost grinder, so I grabbed the grinder housing by the tab in my knockoff Kurt vise, installed a spacer on the spindle shank so I could tension the spindle, then chucked up a 1/4" two flute HSS endmill so I could check the runout of my home-made spindle. 

It's important to note that the bore and internal taper that the collet seats against were cut after I dialed in the workpiece in the 4 jaw chuck.  I chased zeroes for quite awhile before I was satisfied.  I called it good when I could see moderate hand pressure on the chuck body causing deflection.  I believe I was accurate about to the limit of the 1945 SB9A lathe.  Also, I'm not sure how much runout is caused by the taper on the collet nut.  Rotozip collets are tapered on both ends. 

All in all, I'm satisfied with it.  I think it's passable accuracy for a toolpost grinder.  Especially something home-made.  The runout of the spindle bore is a tiny bit less, but I can't reach far enough inside the bore to check the rear taper. 





A touch more than .0015" runout.   I don't think making another collet nut would help much, but it would be good practice for internal single point threading. 
This project isn't over, but it'll be on hold for two weeks or so.


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## jeff_g1137 (Aug 19, 2015)

Hi
Nice work, did you do a video.
The runout is not important if you true the grinding wheel, after set on the lathe. is it ?????

jeff


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## Mark_f (Aug 19, 2015)

I love this design. I may borrow it to make one ( if I get well enough to get back in the shop   ). This project is really nice and one that is needed often. Very good work.


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## ogberi (Aug 20, 2015)

I do need to get back to work on this.  Haven't been in the shop to work since the end of July, just too much going on.  I need to pick up a vacuum cleaner belt before I can move on with this project.  I might get some work done on it this Saturday, though.  

I still need to figure a way to true the grinding wheel once it's mounted.  Need to buy a diamond tipped dressing tool first, though.  I used to have a carborundum dressing stick, looked like a screwdriver, but loaned it to a friend and never saw it again.  It was handy, and did a great job freshening up the wheels on my bench grinder.  

I have some Norton cup wheels that I'd like to use on this, but have to make an arbor to do so.  I also have a dozen 3" NOS carborundum brand wheels with a 1/2" bore.  Those should work nicely.  A side project to this is a fixture to hold in the 4 jaw chuck to allow me to use the lathe as a tool grinder.


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## ogberi (Sep 13, 2015)

A bit more work on this, only a little bit.  Still lots of family stuff going on, none of it good.  Got in some shop time to help put my mind at ease.

Started with a nice big chunk of aluminum bar stock.  It's crapaloy, gummier than 6061, but still turned decently.
Decided to try out a carbide tipped blade on the sawzall to.  It actually cut very nicely, but I need to either buy a bandsaw or build a power hacksaw. :/



Once I had hacked off a chunk, I grabbed it in the 4 jaw and set about making it look like a pulley.  IE, removed everything that wasn't pulley-like.  No dimensions, just seat of the pants.



Drilled a hole, then got out a teeny tiny boring bar and had at it. 




Once that was done, I removed the big 4 jaw and slapped the Taig 4 jaw chuck on there.  I have an MT to 3/4x16 adapter for that. It's MT2 and needs a sleeve, and I'll order the MT3 to 3/4x16 once my hobby funds aren't depleted.
The lathe looks a bit silly with that tiny chuck on there, but it works just dandy.  The task with that setup?  Parting off. 

Yep.  Parting off.  Deep parting, lots of stickout, in gummy aluminum.  The key is to indicate the tool holder so that you're as close to perfectly perpendicular to the spindle as possible.




Getting there.....



All done.  No chatter, no problems, no issues.  I ran the lathe in it's slowest backgear speed, used WD40 as lubricant, and cleared the chips once in awhile.  Steady, consistent feed is the key.  You want the tool to cut, not rub, but you can't crowd it too much either.




Swapped for the 3 jaw chuck (soft aluminum jaws, won't mar the workpiece, but has about .003 runout, I should have bored the jaws but didn't think to...)
And took care of the other end.



That's it for now.  I still need to drill and tap for a set screw in the shoulder of the pulley, and make the much smaller pulley for the grinder's spindle.  I still need to bodge up a quick & dirty motor mount to see if the little motor I chose for this has the oomph to run the grinder, or if I need to find something a bit beefier.

More progress to come, but I don't know when.


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## mattthemuppet2 (Sep 13, 2015)

Hey ogberi, I have a multi ribbed belt off a treadmill that you can have if it fits. Let me know and I'll dig it out of the junk and measure it. Pretty sure I still have the large plastic pulley too.


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## ogberi (Sep 24, 2015)

Hi All, 

Epic Fail. 


The induction motor I started out with wasn't ballsy enough to keep the spindle speed up, so I tried two different DC motors utilizing the DC speed control from my Atlas horizontal mill.  

Second motor did the trick, spun the spindle up to about 8K RPM, which is good for a small 1/8" shanked grinding stone.  

It left a *beautiful* finish on some turned stock, but after about 4-5 minutes at that RPM, both bearings thoroughly crapped the bed.   The first warning was a sudden howl and the stone wobbled the tiniest bit, then a split second later both bearings came un-stuck internally and the motor threw the belt.  Where before the spindle turned buttery smooth, now it chunks and grinds and barely turns.  

So, the whole mess goes in the 'aww, crap, maybe there's something useful in here' tote.  Minus the DC motor.  That went back in the cabinet, because there's nothing wrong with it. 

Soooo...... I sat down, cracked a beer, and lit a stogie.  And stared at the whole sorry mess.  

Here's my new thought.  

I have my Taig lathe headstock.  Right now it's serving as a vertical head on the Atlas mill.  Being that it mounts on a 30 degree dovetail surface (and I have a 30 degree dovetail cutter), I think it may be possible to machine a plate/mount combo that replaces my QCTP to allow me to use that spindle assembly as a toolpost grinder.  Not a QCTP mountable deal, as the recently-deceased one is, but still useful.   There are T-slots all over that spindle housing, so I'm pretty sure I can dream up something from the scrap pile for it.  

So, this project has had a thoroughly irritating setback, but it ain't over.   I intend to build a toolpost grinder, and I will.  I have the need for one to get my 3 jaw chuck back into usable shape, so dang it, I gotta figure something out.


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## ogberi (Oct 18, 2015)

So, while nursing both a beer and a cigar along, I removed the compound from the South Bend and set the Taig headstock on there.  Frowned, then removed the 4 jaw chuck, and slapped in a dead center.  Put a drill chuck & center drill on the Taig spindle, and moved them up to each other.    A split second later, I was digging through the scrap bin looking for a particular piece of aluminum plate I'd tossed in there awhile back.   A big chunky bolt sacrificed it's head to the cause, some mill work, some lathe work, another cigar (but no more beer) and I have this. 




It's held down by the plate, with some 45 degree dovetails cut in it.  I turned a suitable replica of the tapered knob that is on the bottom of the compound, drilled and tapped it, and bolted the plate to it.  




There is a spigot on top of the dovetailed knob, and a recess in the plate.  That locates them together nicely.  I slip the dovetailed plate into the Taig headstock, and tighten it down.  Then, install it in on the cross slide, 
set the desired angle, and tighten the set screws for the compound down.  

How close is it?  Insanely.  



No shims.  Everything is tight.  It's a teeny-tiny hair below center.  Enough that I'm not worried about it. If need be, I think a doubled over piece of foil under each side of the Taig headstock (between the headstock and cross slide) will do it. 

Next up - A motor mount.   I got a nice 1/4 hp 3600 rpm motor up and running, and turned a steel pulley for it to utilize a flat belt (vacuum cleaner belt, actually)  Given that the headstock is covered in T slots, 
I don't think it will be a difficult thing to whip up.  

So, depending on how much time I have this week, I may be able to get it up and running by this weekend.   

It's nice to have something go right for a change.


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## hman (Nov 5, 2015)

Great save!


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