Scraping in all bearing surfaces on my Wards/Logan 10"

Richard King 2

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I see Nelson linked the "Testing Machine Tools" George S book above. Those spec's in there are the ones Connelly based his spec on. The spec's in there are more complete too.
 

Rex Walters

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Rex, looks good. I didn't read it word for word....though.... Be sure to relieve the middle 40% of the slides approx. .001" so they don't rock. Be sure to lock the tailstock down when making the tests, That test bar in the TS quill is a bit long. I would also use some Phenolic between the TS halfs that is glued down. Good scraping :) you must have had a good teacher :);)

Whoops! I relieved the sliding ways in the middle (less than a thou) and I did lock the quill in the tailstock, but I didn’t lock the top half to the bottom or to the bed. I’ll test that today and see how much of I need to correct.

Phenolic sounds like a perfect material. Thanks.

Thank heaven I had a good teacher - I shudder to think of how many more bad mistakes I’d have made with only YouTube and HM to guide me. Following the class(es — in my case — slow learner) with a real project has been extremely educational.
 

Rex Walters

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Do you want to borrow it? I made 2 different sizes.

Nice work! Mag base parts were a clever idea. Were you able to radius the inside edges of the slot in the C foot part? The only way I could figure out how to do that was with a custom ground cutter and somewhat tricky workholding and alignment in the mill.

If you are anywhere near San Jose, I’ll definitely take you up on your generous offer. It’s a fairly small 10” lathe. John York’s large Kingway is too big for my vees.
 

Rex Walters

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If you are anywhere near San Jose, I’ll definitely take you up on your generous offer.

I’ll also 3D print a plastic foot for the ball end in exchange. I think it’s important to average out the bearing on a scraped surface instead of using the point contact of a ball. Seems like individual scrape marks would drive you insane otherwise.
 

Rex Walters

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Be sure to lock the tailstock down when making the tests

Whew!

I just dug out the locking parts and indicated with the tailstock locked down. It did seem to affect the result, but only ever so slightly (about half a division or 0.00025" at the end of the test bar, but in the wrong direction with the test bar tipping down). It's not enough to worry me greatly — I think a heavy stoning will be enough to get it back to perfect, definitely no more than a single scraping pass on the back half.

One other thing I want to run past Rich (and the collective wisdom of the group): since the fit of the step on the base into the channel in the upper half is already a sloppy fit, I used that most precision of tools, a triangular file, to adjust the alignment in the horizontal plane (i.e. the top half spinning around the Y axis). I reasoned the front surface of the steps on the headstock side were the most critical, so I carefully filed away minute bits of metal on the leading edge of one of the bumps until the test bar showed no deviation in the horizontal plane when the top half was pushed firmly agains the headstock edge of the steps.

My plan is to mill off the back edge and then glue in a shim that I'll file or scrape to a tight sliding fit in the upper channel. As long as the headstock edge is already adjusted for alignment, then milling/shimming the trailing edge shouldn't be critical to alignment (just adjust for a tight sliding fit). Does that seem like a reasonable plan?

I was happy to see that McMaster-Carr sells sheets of "Garolite CE" as thin as 1/32" quite cheaply. I just ordered a 1' x 2' x 1/32" sheet (way more than I'll ever need) for ten bucks in case I need to shim up the tailstock as I suspect. Per their website:

"These Garolite CE sheets are often fabricated into parts where high strength is not required. They are made of a phenolic resin with cotton fabric reinforcement, which makes it easy to machine into mechanical parts, such as pulleys, gears, bushings, and washers. Garolite CE is sometimes called canvas-grade industrial laminate, phenolic, and Bakelite."

I saw in an old post of Rich's (elsewhere) that he recommends 3M Scotch-Weld Epoxy EC2216 for phenolic, and 1838 Green for for Turcite/Rulon. The prices for those from McMaster made my eyes water ($54 for a 3.3 oz tube of 2216). Since this is a fairly static way on a hobby machine, I'll likely just use some cheap slow-set epoxy from the hardware store.

How machinable is phenolic? Can it be scraped?
 

Rex Walters

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How machinable is phenolic? Can it be scraped?

Whew, caught it in time. Found someplace where Richard specifically recommended NOT USING ANY PHENOLIC UNLESS IT IS "linen grade" (which can be scraped). I just changed my order to Garolite LE (vs. CE) which is linen for only a few pennies more. I'd still like to find a cheaper glue than the 3M 2216 Rich recommends (I wonder if even a thick gel-type CA glue would suffice?).
 

Richard King 2

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You can use any 2 part epoxy with a 8+ hour dry time. I did a lathe in Oklahoma last fall and we used J D Weld that I bought in a Auto Store. ( I brought brand new Tri-Star Epoxy, but TSA said it was hazardous and took it) Be sure to either bead blast or sand paper the shinny side of the Phenolic. Also clean with Acetone or fast dry brake cleaner or electrical contact cleaner. On the 3M products I think both would work on either product, but 3M info line recommended those for the different materials.

I wish you had asked about the between the halves key as I would have never filed a perfectly good surface to correct an issue on the ways. I would have first used some shim stock between the bottom and the way to get the bar alignment and then scraped off the opposite side of both ends. You may have had to set scrape the complete bottom to get the top of the bottom half so it runs parallel to the cross-feed travel.

If I were you I would put it on a mill and indicate in the front 1/2 (the one you filed) and then kiss that side to be sure it is straighter then a filed surface, Then go to the other side and mill out the back end then mount a piece of square key stock and cap screw bolt it down. I wouldn't glue some shim on the one you filed or back side.
 

Richard King 2

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If you want, bring it with next week and we can figure it out (for those who don't know, Rex is assisting me teach the Vacaville CA class. He has attended 2 of my classes and I have a lot of confidence in him and his skill. Also I sent a vintage used Challenge brand 36" plain (no angle) camel back that will need to be touch up out via UPS, so your club has it for the next lathe bed.
 

Rex Walters

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If I were you I would put it on a mill and indicate in the front 1/2 (the one you filed) and then kiss that side to be sure it is straighter then a filed surface,

Yup, that was exactly what I just decided - thanks for the confirmation. It was far enough out that I knew I wanted to mill it eventually, the filing was just a quick and dirty way to get it aligned horizontally enough to make reading the tip in the vertical plane easier (so I could just sweep along the test bar instead of continually having to find the top via maximum deflection).

The fit was pretty sloppy regardless. I know at least some of the slop was my fault, but none of the mating surfaces between the two halves had been precision ground even at the factory, just rough milled. I was kind of shocked at just how out of flat the top half was to begin with.

I should have taken the time to do it right, of course, but I reasoned that way is just used to (VERY infrequently) adjust the tailstock way set over for cutting tapers (or not). Like most people, I usually set the tailstock for zero taper when cutting between centers and avoid setting over like the plague.

For the rare occasions I did want to cut a taper longer than my compound travel, I even built a GHT designed tapering jig quite a while ago expressly to avoid adjusting the tailstock off zero once I had it dialed in! Basically just a dead center with an adjustable offset and an MT2 mount.

Found that McMaster also recommended a slow cure JBWeld epoxy for their “Garolite” material. Much more reasonably priced, so I ordered some along with a 1’x2’ sheet of Garolite.

Anyway, I’m definitely bringing the whole lathe with me next week. Looking forward to getting your advice on the more critical components coming up. I’ll hold off on doing the actual glue up and final scraping of the phenolic until the class. I’ll do the preparatory milling etc. tomorrow.

Thanks!
 

astjp2

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Nice work! Mag base parts were a clever idea. Were you able to radius the inside edges of the slot in the C foot part? The only way I could figure out how to do that was with a custom ground cutter and somewhat tricky workholding and alignment in the mill.

If you are anywhere near San Jose, I’ll definitely take you up on your generous offer. It’s a fairly small 10” lathe. John York’s large Kingway is too big for my vees.
Built a small one and a large one, and USPS is only $8 away
 
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