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High School 9A Spit and Polish

panabax

Aluminum
Joined
Mar 28, 2015
Location
Dallas, Texas USA
A few weeks back I won a public auction for some machine tools from a local school district. Included in the bunch was a 9A with a 4' bed. For some stupid reason, I did not take pictures of the thing in its "as purchased" state. Let's just say, it was rough.

I bid on it basically because I wanted the large dial assemblies, the cast iron legs and the chip tray. I figured I could part the rest of it out and get my money back and have the stuff I wanted for free. As it turns out, it was in much better shape than I had imagined so I am in the process of cleaning it up. I have finished the bed and carriage. I think the next item on the list is to build the base for it. The legs and chip pan are Logan. The legs are awesome the chip pan, not so much. It's pretty thin and beat up. I have tried to "work on it" but I think I am going to just fab up a heavy chip pan to go with the cast iron legs.

Here are the photos from the auction.

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The bed was covered in a thick layer of grime. After degreasing, it turned out to be in pretty good shape, except for a fair amount of rust at the tailstock end where it had not seen enough oil to grow that thick layer of sludge and dust that was armor coating the rest of the bed. In order to remove the rust without damaging the bed, I created a trough out of 2x4s, lined it with plastic and created an electrolysis bath. Here are some interesting videos of the bed in the trough while the electrolysis is running. You can really see how bad the tailstock end looks, but it is all just surface rust with zero pitting. If you pay attention, you will see that the anode setup changes from one video to the next. The first shows one piece of stainless sheet as the anode. In the next, the entire bed is encircled in angle iron or whatever I had handy. Apparently stainless makes some nasty electrolysis byproducts. The process is also "line of sight" so the only way to get good action on something like this is to have an anode that basically surrounds the piece.

If you watch the videos you can see the bubbles pouring off the bed where the major rust is.

[video]http://www.supermotors.net/getfile/1057252/fullsize/img_1378.mov[/video]

[video]http://www.supermotors.net/getfile/1057253/fullsize/img_1380.mov[/video]
 
Here are more pictures after electrolysis. You can see that all the rust has now been converted (back) to black iron. You can also see what it looks like after just a few minutes of cleanup. I used nothing more abrasive than a superfine 3M pad to clean off the black iron residue that the electrolysis creates. Another nice thing about the electrolysis is it lifted almost all the paint off the bed. The remaining paint was removed with chemical stripper and elbow grease.

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Here is the bed before and after painting. I also totally disassembled the carriage and apron and ran them through a similar electrolysis process. However, for the smaller parts I used a 5 gal bucket with 6 one foot sections of rebar lining the inside of the bucket to envelop the parts. I then totally stripped all remaining paint, repainted and reassembled the carriage and apron with all new felts. I have not painted or polished the traverse wheel on the apron. That is still on the to do list. Also, I went ahead and put the small dial on the cross slide for now since the large dial is on my other 9A. Eventually it will get its dial back. I am really happy how well this has turned out so far. I think the next order of business will be to get the base ready.

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What is the vintage of your lathe (serial number)? The ways seem to be in fairly good shape. It also seems to have escaped the many carriage-chuck collisions that many HS lathes experience.
 
What is the vintage of your lathe (serial number)? The ways seem to be in fairly good shape. It also seems to have escaped the many carriage-chuck collisions that many HS lathes experience.

Serial No. 56123NAR10. Catalog No. is CL744A. It is a 1967. I also have a 1944. The bed on the '44 is in much rougher shape. The bed on this one still has a lot of frosting, albeit on the tailstock ways. Really, I was expecting the bed to be a boat anchor but it looks like it did not get that much use and was well cared for before it became totally neglected. Fortunately it had a good coat of oil on everything except the tailstock portion of the bed before it went into moth balls. That oil, combined with a decade of dust, is as hard as bed liner.:cheers:
 
Here are some additional photos. The parts are starting to come back together now. I am going to switch to building the chip pan/motor mount now and get back to assembly once the base is done and I have somewhere to put all these parts. No reason putting it ALL together on a bench it won't be mounted to. This sucker gets heavy with all the parts attached.

All 5 of the cheese head screws that mount the QCGB and the lead screw bearing were sheared on this lathe when I got it. I ended up getting some low head cap screws from Fastenal. They are 5/16-18 x 3/4". You can see one installed in the third picture. I was thinking about pulling the cheese heads off my 1944 bed for this rebuild, but after installing these screws, I must say I prefer them a lot more than those cheese head screws. I would also venture to guess that if SB was still in business and making the 9A, they would now use these screws (I don't know what Grizzly uses and I'm not counting the "new" South Bend). Here's a link to the screws if you ever need them. Low Head Cap Screws

I do have a couple of questions:

1. My understanding of the paint/don't paint rule of thumb is if it is raw casting paint it, if it is a finished surface, do not. So, is the handle that tightens the tailstock around the tailstock quill a "finished" surface? In other words, is that little handle on top of the tailstock (not the one that tightens the TS to the bed) painted or polished?

2. The bed on this 1967 9A has two threaded holes in the front face of the bed just above the QCGB. They are shown in the last picture. My 1944 9A does not have these holes. I do not recall removing anything from them when disassembling the lathe. What are they for?

TIA

Baxter

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My understanding of the paint/don't paint rule of thumb is if it is raw casting paint it, if it is a finished surface, do not. So, is the handle that tightens the tailstock around the tailstock quill a "finished" surface? In other words, is that little handle on top of the tailstock (not the one that tightens the TS to the bed) painted or polished?

Okay, so I got off my lazy butt and searched through some threads with pictures and it seems the don't paint anything but raw casting rule holds true on this handle. To the bench grinder (polishing wheel that is) it will go.

Baxter
 
The bed on this 1967 9A has two threaded holes in the front face of the bed just above the QCGB. They are shown in the last picture. My 1944 9A does not have these holes. I do not recall removing anything from them when disassembling the lathe. What are they for?

I believe that a control was once mounted there.
 
2. The bed on this 1967 9A has two threaded holes in the front face of the bed just above the QCGB. They are shown in the last picture. My 1944 9A does not have these holes. I do not recall removing anything from them when disassembling the lathe. What are they for?

Micrometer carriage stop bracket for using the stop close to the headstock.

Hole spacing should be 2-1/8" center to center.

Steve
 

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Serpentine Belt Drive

Okay, so I am making a little progress on the stand and the drive system. Here are a few pictures of the progress so far.

The chip pan is 1/8" plate. The two pedestals for the lathe feet are two (2) 1/2 pieces of plate (hot rolled). I would have preferred a 1" thick slab of 1018, but the cost was more than I could bare. The left hand plate is larger than the right hand plate in order to accommodate the drive system as well. Eventually, the chip pan will have angled sides.

The serpentine drive is setup to use a 32.5" k belt, easily available from your local auto parts store. The large step on the countershaft step pulley is 5" diameter. The whole thing will now fit within the boundaries of a 24" table. In fact, it could be even thinner if I cut if off closer to the front of the lathe. Basically, with a 32.5" belt, the center of the countershaft is about 10.5" behind the center of the spindle bore. If you add a 2.5" radius for the large step, that puts the outer boundary (not counting the belt thickness, at 13" behind the center of the spindle bore.


Baxter

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I am continuing to make slow progress on my new 9A. I am currently working on the serpentine drive system. I need to finish the drive system so I can finish the bench so I can paint the bench so I can have somewhere to assemble the new lathe so I can finish the new lathe. It is about 90% complete now, but I can't really assemble it until the bench is done.

Attached are photos of the new countershaft driven pulley. It has had the grooves cut, but the groove peaks still need to be radiused. It is 5" in diameter which is the same diameter as the large step on the countershaft step pulley.

The bulk of the space savings for this drive system is a combination of the closer relationship between the countershaft pulleys and the spindle pulleys (about 10.5" between bore centers) plus the reduction in diameter of the driven countershaft pulley. The original pulley is 12-14" in diameter. Obviously 1/2 of any reduction in this pulley diameter equates directly to space savings at the rear of the bench. In order to maintain, approximately, the same ratio between the motor and the countershaft, I am using a proportionately reduced motor pulley. The reduction in pulley sizes is made possible by the much greater power transmission capabilities of the serpentine belts.

The poly-v groove is 40 degrees. I am using K belts which have a 3.56mm distance between grooves (groove pitch?). I've also attached a photo (but not a very good one, sorry) of the parting tool I am using to cut the grooves. It has a 40 degree point on one end and a concave radius on the other end to radius the peaks of the grooves. These pulleys are actually a lot easier to make than I original thought they would be. Basically you set the compound at 20 degrees, cut the first groove to the proper depth, retract the compound, move over 3.56mm, and cut the next groove. Repeat this process until you have cut the number of grooves on your belt, then radius the peaks. The setup is simplified by the cheap DRO on my current 9A (igaging). It took about 20 minutes to do the grooves on this pulley.

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I finished the countershaft driven pulley. Here is the nearly completed drive system. The shaft and both pulleys are keyed. I will let the step pulley "float" on the shaft to allow it to automatically align itself (to make up for any deficiencies in engineering and/or manufacturing which are sure to be present). The driven pulley still needs to be drilled and tapped for a set screw to keep it from moving laterally on the shaft.

Next order of business is the motor mount. I am planning to use a 1/4" plate with a long collar to allow it to rotate around the same pin as the countershaft mount rotates around (currently a piece of all thread which will be replaced). I will then use a thumbscrew or some such to make tension between the motor mount plate and the countershaft mount. That will take up any slack in the motor belt and allow the motor and countershaft to pivot as a unit when tension is released to change the belt from one pulley to another.

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I am one step closer to finishing the drive system. Here is a picture of the motor mounted on a swiveling plate. The plate pivots on the same bar that the countershaft assembly pivots on. That is a 29" 6 rib K belt on the motor. There is about 3/8" below the motor plate to apply additional tension to the belt, as needed. I have not yet decided how I will make the tension. My original thought was to weld some bar stock to the motor plate perpendicular to the plate so that it comes up to where the cross member is on the countershaft assembly. I could then drill and tap that cross member and run a thumb screw through it to create a moment force which will rotate the motor plate down. Then, the countershaft and motor mount will move as a single rigid unit when tension is applied and relieved on the drive belt.

However, it would be easier to run a tensioning bolt from the base of the lathe bed mount. The only negative to that is that the motor mount and the countershaft assembly would not be one pivoting unit. The last idea I had was to simply run some type of spring from the motor plate to the lathe bed mount so that the motor mount is always under tension but is never rigidly coupled. Actually, a torsion spring wrapped around the pivot bar and tending to rotate the countershaft assembly and the motor plate away from each other would be ideal. Any suggestions on a pretty stiff torsion spring with a 1/2" diameter hole?

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Since the drive system is basically done, it is time to finish the table. I am mounting the lathe on the cast iron legs it came with, but I made a very heavy chip pan to go between the legs and the lathe. There are two blocks 1" thick where the lathe feet mount. One has extra depth to secure the pivoting drive system. Here it is with its first (still wet) coat of paint.

Baxter

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