HOME
What's New

 

Workshop Stuff

Workshop

Moving the mill

Spindle Noises

ShumaTech Digital Readout

ShumaTech DRO Continued

ShumaTech
DRO-350 Repairs


South Bend 9" Lathe

South Bend 405 Lathe Bench

Grizzly Mill Revisited

Surface Grinder Rebuild

Surface Grinder Continued

Grinder April 6, 2008

Grinder April 20, 2008

Grinder August, 2008

Grinder September, 2008

Grinder November, 2008

Grizzly G3103 Mill
Rebuild

Grizzly G3103 Mill
Rebuild - Part 2

Moving the Shop

Moving the Shop 2

 

 

Email Jim


 workshop.gif
DoAll D624-8 Surface Grinder Continued
Updates

Week of November 21, 2008

The grinder is finished.  11 months of work and I'm pretty pleased with the outcome.  The last few months have been busy ones and I haven't had the time to spend to do much more than take some pictures and make some notes on my progress. 

June/July 2008

The lower saddle ways were done.  The grinder had been moved to its new home in the corner of the garage and leveled. The top saddle ways were flat, true and square to the lower saddle ways and the column ways.  Best of all, I was getting closer to having the table ways finished.  One of the last checks involved using my shop made "KingWay" type tool, which was used to ensure that the inverted Vee way was parallel to the flat way.  My tool, having only a single vial, can only check for level in one plane, but this is not an issue if additional levels/vials are used to make sure that the ways are level in the length plane.  To level the table,  I used my box level and a couple of vials I had made with no curvature.  Without a barrel shape or a slight bend in the vial, the sensitivity of the bubble in the vial is greater than the 0.0002" per 10" of my box level.  Actually, they're too sensitive.  Any vibration on the garage floor would put the bubbles in motion, but as long as the bubbles stayed somewhere near the center of the vial, I knew that the table was pretty darn close to being level.  I used the box level to confirm this.

level table
one side


other side
check center



Once I had shimmed the table level at the Airy points, the "KingWay" tool was used to check that the inverted vee and flat ways were flat and not angled toward one end or the other.  The final step was to use my engine hoist to lift the table and set it on the saddle to perform the final scraping in process.  This step took about two weeks of bluing the table or saddle ways, setting the table on the saddle, lifting it off and checking the pattern of high points, and scraping them flat.  Once I had a good patten with the table centered on the saddle, I tried setting the table in different positions - as if the table was sliding right or left - and made my final passes.

Another check I made was to block my 36" granite straight edge, level and square, to the top table pad.  I then used a tenths indicator mounted on the wheel housing to check for any irregularities in travel.  Since the table pad was badly pitted and corroded, this allowed me a true, flat surface to compare the table travel to.  Finally satisfied with my scraping job, I repaired one damaged thread for the coolant return fitting, painted the table, and mounted the rack for manual table travel. 

I was expecting that I would need to make some adjustments in the mounting of the rack, as I had removed a fair amount of metal from the ways.  However, I was pleasantly surprised when after bolting down the rack and trying it against the pinion gear on the saddle, it was perfect.  I applied Prussian blue to the teeth of the rack and ran the rack from end to end in one direction.  I got a good contact pattern on the pressure side of the teeth and no contact on the other side.  I repeated the test for the other direction with the same result.   With the table at rest, there was a small amount of backlash which indicated that the mesh was not too tight.  This is a little confusing to me as neither the rack or pinion appear worn.  I don't know how much backlash this machine had when new, but it would appear that it was more than it has now.  There are dowel pins that locate the rack on the table and they fit without play, so there is only one position for the rack to attach.  I have given this situation a fair amount of thought and the only conclusion I can make is that the machine's designers allowed enough clearance between the rack and pinion that it could be rescraped without having to using up all the clearance between rack and pinion.

painted table
The rack is installed and the table's been painted

With the table on I had a couple more things to do before I would be ready to grind the table pad and chuck.  First I needed a more permanent home for my rotary phase converter (RPC).  I had been testing different circuits of the surface grinder with the RPC parts attached to a prototype board, while the 5 hp motor sat on the floor.  The RPC now needed a dedicated home. 

September 2008
I've done quite a bit of work on DC circuits included designing some low power amplifiers.  I've also done tons of electrical work on cars.  What I had never done was to venture into the realm of 3-phase AC wiring.  There are a lot of sites on the web that go into great depth on how to convert single phase 220 household power into something suitable for powering industrial equipment.  Many of these pages are written by folks who have a much better grasp of the theory and electrical codes than I.  With this in mind, I will leave how I built my RPC out of this article.  If you are interested in building one for your own use, I suggest that you start with the "sticky notes" on the Practical Machinist site "Transformers, Phase Converters and VFD" bulletin board.

Between Ebay for a 5 hp 3-phase motor, some of the capacitors, switches, indicator light  and Grainger and my local home improvement store for the remainder, I spent about $550 for the whole thing.  This is about $150 more than the least expensive 5 hp units seen on Ebay, but a whole lot better quality.  Also, being on wheels allows me to move it to where it might be needed in the future.  Building it was also quite a learning experience and after the research I did, I no longer am completely ignorant about 3 phase electricity.

The build went very quickly once I had assembled all of the parts from the different sources.  No horror stories and no problems with balancing the phases.  The one problem I did have was with the wiring for the grinder and I had fortunately read about it, so I was able to fix it in moments.  When I wired up the plug to power the grinder's electrical box, I made sure that the manufactured leg of the power was not on the circuits that powered the step down transformer, but that was about all I took into consideration.  When I fired up the hydraulic pump motor, I had no hydraulic pressure.  After a few choice words and a sinking feeling, I realized that the pump motor was turning in the opposite direction of the arrow stamped on the pump.  Long ago, I had read that to reverse the rotation of a 3-phase motor, you may swap any
two of the wires.  I  reversed the two connections on the plug and moments later, I had hydraulic pressure.

rotary phase converter
Grinder with RPC
Frame for the RPC
Finished RPC at right

The fact that I had run the pump backwards was not the only hydraulic issue I encountered.  Earlier, I had been going through the machine and trying to find the correct hydraulic filter, which for my 1967 D624-8, is a Purolator 572759 ( ID= 1.000/.997, OD = 1.781 max./1.735 min., length = 4.500/4.438,).  I found a comparable filter at Filter Mart, part number 02-0004.  When I removed the bowel that holds the filter, I found that the previous owner had installed a filter that was about a half inch too short.  A filter that is too short is like not using a filter at all, since the oil is able to flow around, rather than through it.  I drained and cleaned the tank, flushed the system and crossed my fingers that I wouldn't have any troubles with it.  I got lucky and it seems to perform quite well, but it was necessary to purchase a hydraulic gauge in order to set the pump output pressure.  I also readjusted the release pressure of the pressure relief valve.  Once I had the pressure set to specifications (300 PSI for the Continental Hydraulics 113620-E Hyd Pump), I noticed that the pump quieted down and the motor wasn't working as hard to spin the pump.  The hydraulic system seems to be in pretty good shape, though I do get a little seepage from the seals on the hydraulic cylinders. 

When the hydraulics are switched on, the Bijur lubrication pump is also powered up.  Since I had already found and replaced the clogged metering jets early in the inspection and repair process in mid-summer, it works like a champ.  I had replaced the 3 size 0 - B2495 and 3 of the size 2 - B2497 metering units.  In the past, I have had very little luck trying to clean Bijur metering jets, so I didn't even try messing with these.  After all of the time I have spent scraping the ways, the last thing I want to do is to run this machine with little or no lubrication.  While looking over the lubrication system, I found it interesting that only the vertical and longitudinal axes, as well as the vertical lead screw use metering jets.  The saddle in/out axis (Z
ways) are lubricated by the excess table lubrication. The run-off from the X axis table ways collects in depressions, then enters the vee ways from holes directly above them.  These ways do get more than enough lube and tend to drip a bit from both the front and rear of each vee way, but it's better to have to clean the drips than to have dry slides.

September 2008
The last thing I needed to take care of before I could give the grinder a try was to get the coolant working.  I had noticed that the pump was locked and wouldn't spin, but figured that I could repair it without much trouble.  This turned out to be correct.  It appears that the impeller just rusted to the housing.  I spent a couple afternoons stripping the tank, pump, filter, and motor down to their basic parts.  I wire-brushed the impeller and housing to clean off the rust.  I opened up the filter to find that just like the hydraulic filter, it was too short.  I wonder what the work looked like using unfiltered coolant.  The filter that was there was a charcoal filter for drinking water purification, but since the tank is made for a double length filter, this single length one wasn't doing anything except maybe slowing down the flow a bit.  This grinder has the "Cool Grind" setup where the coolant is directed to special flanges on the wheel adapter.  The wheels have perforated paper labels that allow the coolant to enter the wheel and be forced out to the cutting edge by centrifugal force.  In order not to clog the wheels, extra filtering is added.  In addition to a new filter from McMaster - a 20" filter # 4411K65, I also added a felt bag that catches sediment as it enters the tank.  This cuts down on the amount of material that ends up in the tank and filter.

coolant pump 1
coolant pump 2


coolant pump 3


I brush painted the 20 gallon holding tank with Rustoleum enamel and let it cure for a week or so before filling the tank with a coolant/water mixture.  I have plumbed in a line-lock nozzle and a valve to switch between the Cool Grind function and the normal flood coolant.  When I initially ran the pump, I got a little seepage from the seal between the impeller and motor, but this sealed itself after it had been run for a while.  It is replaceable, but who knows what pressing the impeller off would be like.

October/November 2008
With everything finished, I set out to grind the table and chuck (see this page).  As I explained in that installment, I encountered some spindle issues.  The taper on the grinder's spindle was worn from use - and probably not tightening the adapter before starting the spindle.  I was somewhat concerned about trying to grind the spindle taper myself on my South Bend 9" using my shop made tool post grinder.  However, I figured I'd give it a try and if I couldn't get the taper close enough to NO run-out, I'd find a machine shop to grind it for me.  I knew that the bearings would need to be replaced as even if they weren't worn, I wouldn't be able to get them out of the housing and back in again without doing some damage to them.  I also knew that they would be expensive.  New Barden 107 matched angular contact  bearings go for over $600 a pair.  I would need two pair.  Ouch!

Next, rebuilding the spindle.