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Daily Shop Improvement

The shaft bearing block design on my lathe was bugging me so I picked up some bronze bushings from PA today. The feed rod and the switch shaft are both 3/4" OD and the lead screw end is 20mm so I got bushings that are 3/4 ID and 7/8" OD and 1-3/8" long. The OD of the bushing measured .880" so about .005" over 7/8" so I bored all 3 holes to .879" for a .001" interference fit. They fit the two 3/4" shafts with .003" clearance so I bored the lead screw bushing to the same clearance spec. I shortened them to 1" long so the oil passage would not be blocked by the bushings. I had to extend the oil passage to the bottom bore as it was only connected to the top 2 bores originally. The factory drilled passage entry was filled with bondo so I dug it all out to expose a nicely bored hole that that fit a 10mm ball oiler after I was finished with the long drill bit. It turned out well and should last forever.

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Nice job beautiful pictures
 
Cast iron is pretty high graphite’s and as such is classed as “self lubricating” to some extent. Adding oil to the mix will give you a nice slippery surface. As the lead and feed are relatively slow turning an oiled cast iron will work quite well. Do a google on cast iron lubricity
 
My Southbend spindle has been running in cast iron for over 50 years and Is still fine.

I have a theory about that (and I have been known to be wrong about many things). In principle, if the shaft is aligned to the machined CI bearing block & adequately lubricated like a good old school N-Am machine, they should run together for a long time. Unless the shafting has been heat treated CI is typically harder so the shafting will wear first. The question is, what is easier/less costly to replace when the time comes. A simple pinion shaft is easy to make. You might be able to re-bush the end of a lead screw, or maybe not depending on the assembly. And something like a leadscrew or splined 4 ft shaft is a typical PITA component to replace if the machine is getting on in age. OTOH, after 50 years who cares unless its a family heirloom.

Enter the offshore machines where they semi-adopted this configuration. Now you have the potential for some degree of shaft/hole misalignment or ratty hole finish or slightly bowed shaft or maybe poor choice of lubrication. Now the seemingly same recipe is a future problem in the making. My power feed shaft was pretty much textbook example. The shaft was unobtanium. I ended up getting it straightened & making a new bushing block using bronze similar to John. Its been running very smooth since then.

If I was modding a machine I would put bronze in every hole! lol. The PA bushings (also available at most bearing shops) are great value if you can utilize them as-is or a bit of turning like John did. You are paying for the shell, not a solid rod of bronze. Now those become the wear point & more readily replaced year 51. It also gives you a chance to correct bad geometry if one inherits a factory problem as the the block can be re-bored.
 

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I never liked the fact that the only off switch for my band saw was a tiny little switch that might be hard to safely get at in a quick emergency. I'm surprised that these are sold with out an emergency stop switch.
20200506_114656.jpg20200506_114605.jpgSo I put one on myself. Its maybe not quite "right" as it doesn't kill power to the entire machine and the coolant pump still runs when it is hit but it kills the motor. And its easy to get at.
 
One of the plastic head wing bolts that locks the belt tension adjustment on my drill press broke. I machined a couple of new ones with steel wings and extended the left one to prevent interference with the slide handle. I have also been annoyed by the short handle on the table height pinch bolt so I machined a longer one to round out my drill press improvements yesterday.
The original wing bolt was hard to reach.

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The new parts.
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Welded wing bolts compared to the originals.

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Much better access.

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Original pinch bolt with 3" long handle compared to the new 6" long one

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Wishing for a new welding table. Actually any welding table. I thought this one was interesting with the lazy susan in the middle. The three John's have a welding table project... it's stalled.



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2.7M views on this one! I hope the author made some money.

 
Hey John,

I watched the build video - there are a few things the same as the one I built - with the side table for the saw - I made mine removable.

Some thoughts: The thin metal for the table top I was not keen on - needs to be thicker in my opinion to try and stay flat and to absorb abuse - also I sometimes tack jigs in place and always nice to be able to grind them off.

The gap around the lazy suzan could be a problem - lots of sparks, grind etc will fall down onto whatever you have below

The permanent turn table in the middle might drive me nuts after a while - would be nice to move it at times, not have it at times, I think the idea of the rotary part is cool but might be better as a separate table you could place onto the bench

I have extension arms you can mount and pull out to length - also vice is detachable so you just have a flat surface to work on - nothing in the way of a frame.

It has potential

I have an AutoCad I did up of a table prototype I can send you if you wish - it is not dimensioned but is to scale and you could develop from there if you wanted
 
I was using the universal dividing head yesterday to space the 10 holes and one slot in the brass disc for the old safe. I was tilting it from horizontal to vertical and then back again. It was very hard to move - it had been doing this since I got it. The dividing head was made by the NEWS Yamatokoki MFG. CO. in Tokyo, Japan, in 1968 (inspection certificate is dated 9.9.1968). Today I decided to find out what was wrong. I had figured that it had to do with the tilt locking mechanism. There are two bolts through the casting that each have a brass “shoe” that engages the operator side dove tail (much like gib locks on straight gib lathes and milling machines) except the shoes are pulled onto the dovetail vice being pushed by bolts.

Disassembly revealed some decades old swarf that had found its way into the bottom of the casting - it was mostly aluminum.

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Here are some more parts

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What was concerning was the deformation of the rotating body and the worn clamping shoes

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I stoned and removed the worst of the deformation on the casting. The brass parts were also cleaned up so that they would be a sliding fit into their bores again. I was considering making new shoes - turns out that they were cut in situ during the original milling of the curved dovetail. So I decided against it.

Here was the original problem (a design flaw). When the bolts are tightened to lock the tilt, they slightly rotate in the bore, taking the shoes with them. This results in the brass shoe jamming in the dovetails. After unlocking the bolts to tilt the head, the shoes jam further when trying to further tilt the head (It is like a tapered gib - the harder you push, the more it locks). I was able to duplicate this jamming over and over again. It would explain the deformation as attempts to free the shoes requires a very large force. Also, since the shoes are not making good contact with the dovetail while canted, more force was used in the past to lock the head - another possible reason for the deformation.

The solution: prevent the bolts and shoes from rotating while being tightened. Enter the Scotch Key (anti rotation pin)

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I used a 3/16” end mill to make the 1” deep hole for the brass pin. I was concerned that a drill might wander off because it was drilling half cast iron, half steel and half brass. Worked great.

Dressed the original brass shoes to fit the dovetail nicely and reassembled. Testing revealed that there is no more jamming and the shoes release every time, making tilting very easy. You can just see the little brass anti rotation pin on the bottom lock (below the gear)

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Sorry for the sideways pictures. Not sure what’s going on...
 
Nice TLC & mods, Rudy. I've often wondered how they locked.
Is the spindle nose threaded for chuck mount? And does inside have a standard taper?
 
Thanks Peter & John. I was lucky, it came with the mill. All change gears and the inspection certificate!

Some dividing heads, like Walter, have a slot in the base casting and the tilt locking happens by squeezing this slot closed with bolts on either side of the rotating member. I think that is a better design still as there in 360* surface clamping contact.

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Yes, the nose is threaded, 21/4”-8TPI. The bore has a B&S taper - not sure which one.

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Rudy you're a tough act to follow, I'm happy if I get parting to work. Speaking of parting, I successfully made collars to keep my lawnmower wheels together and they actually parted off well.
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Then thanks to Brent H I made up table covers for my mill, a bit of hardboard and some left over arborite worked nicely.
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