Lathe Motor and Countershaft Pulleys

Discussion in 'Lost foam casting' started by Al2O3, Nov 26, 2020.

  1. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    As part of the lathe restoration project I started here,

    http://forums.thehomefoundry.org/index.php?threads/dro-mount-for-lathe-restoration.1397/

    and here,

    http://forums.thehomefoundry.org/index.php?threads/lathe-gear-cover.1398/#post-32103

    I converted it from a bench top to a cabinet model with countershaft under the lathe. When I bought the cabinet surplus, I got everything except the 2-step countershaft and motor pulley.

    I temporarily borrowed and installed a 2-step countershaft pulley but only have a single step motor pulley.

    1 Temp Pulleys.JPG

    Seems folks on eBay think the large pulley is worth $150 and the motor pulley $60-$70. With shipping that would be $260+ and that aint happenin for a couple pulleys. I looked/watched for 3-4 months and made offers but apparently the sellers would rather have a part that doesn’t sell so I decided, screw it……..I’ll make them…..after I cast them, it’ll be a good first project to commission the lathe. So I made some lost foam patterns for pulley blanks on my pin router. I need one of the larger countershaft and two motor pulleys. It was easy to make a spare of each pattern since it’s basically all set with only a few minutes of machine time. Here’s the initial pass,

    2 Pulley Blanks.JPG

    After I hotwired the large diameter pulleys to thickness they warped. The large one about an 1/8” out of flat. So I bent them by hand the opposite direction until the they had enough memory to stay flat and then weighted them when I glued them together. Then back to the pin router to finish them up.

    3 Pin Router Detail.JPG 4 Finished Patterns.JPG

    The castings are designed to be about .060” material rich in the OD, faces, and grooves. I may have to do some massaging of the castings to make sure they remain flat enough to turn with the available machine stock……we’ll see about that.

    …sprued them up.

    5 Sprued.JPG

    Coated and ready to be poured.

    6 Pulleys Coated.JPG

    I’m dithering as to whether they will be Zamak or aluminum. -Waiting for weather to improve for casting.

    Best,
    Kelly
     
  2. rocco

    rocco Silver

    Just to sort of quality work we've come to expect from this forum's resident "king of foam"!!

    I'm curious though, what type of cutters are you using, especially the one for the v-belt groove?
     
  3. Your damn sprues look better than my finished castings:(
     
    Tobho Mott likes this.
  4. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Thanks Rocco. For the groove, the first thing I grabbed for was one of the wings off a finger joint bit but the angle was too shallow. I was going to resort to using a straight bit and slightly more elaborate fixture then remembered I had some style and rail cabinet door bits and low and behold, the wing on one was the correct angle of 17 degrees. I just set the fence and depth of cut, clamped that white scrap board in place as a stop, then slid the fixture (board with a pin:D) against the fence and stop with one hand while I spun the foam disc with the other. Then flipped the disc over and repeated.

    7 Groove Bit.JPG

    Think your pulling my crank there Andy cuz I've seen your castings and they are impressive. Happy Thanksgiving.

    Best,
    Kelly
     
  5. rocco

    rocco Silver

    Better to be lucky than good:p
     
    DavidF likes this.
  6. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Aluminum it is. Cast the first two and they looked fine…

    8 Pulleys As Cast.JPG

    So I cast the others and degated and media blasted them.

    9 Pulleys Degated.JPG

    They’ll need to be heat treated but I have some pulley castings.

    The entire morning’s bounty.

    16 Lathe Castings.JPG

    Best,
    Kelly
     
    rocco, oldironfarmer and Tobho Mott like this.
  7. Kudos on successful gating and beautiful work!
     
  8. Tobho Mott

    Tobho Mott Gold Banner Member

    Very nice indeed!

    Jeff
     
  9. Jason

    Jason Gold

    Those look really nice, but dumb question guy here... Why didn't you just turn some new pulleys on a lathe???
    Or is this a which came first chicken/egg thing?
     
  10. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    The larger pulley is 9" in diameter and 1.25 thick when finished. I didn't have a chunk of stock that size and buying one would have been cost prohibitive and machining it on one of these lathes would take forever. I'd probably hog it on the rotary table on my mill and finish machine it on the lathe if I went that way. It'd be more practical for the smaller pulleys which are 4.5" OD.

    The castings will still need to be turned on the lathe and balanced as even though I try my best on the foam patterns, they wouldn't be near close enough to just bore a hole and broach the keyway.....they'd shake like all get out. Now, that's probably the first operation I'll do when I machine them, then make an arbor to mount it and machine the grooves and faces. Then they'll need to be balanced. I can only statically balance them but that should be good enough. Here's a picture of the OE pulley. Look at all the weight removed to balance this one......

    Pulley Balance.jpg

    You can buy these pulleys on eBay but sellers want $150 for the larger and $70 for the smaller ones. I don't think the lathe is worth enough to spend that on two pulleys but on the other hand, I wouldn't sell the ones I made for that......why go to the effort? The same reason a dog licks his......(that one's for you Jason)....because he can. LOL!!

    You can buy single step pulleys more reasonably but then you wouldn't have the large speed range. I have a 3ph motor and VFD but you can still select your happy speed. These lathes still have quite a following amongst collectors and hobbyist thus the parts prices. When they were introduced (not sure when but they were full steam by 1930s) they were a hit with hobbyist because they were relatively inexpensive, portable, and made .001" precision a reality for a home gamer.........but consequently, they are not very rigid and a very light duty lathe.

    By my standards they are a bit of a toy and certainly not the machine I would have bought for myself, but given I inherited (actually two) them and the family history (since 1947), it could be in the family for 100 years when/if it passes to my son.....but I needed to make upgrades like DROs, QCTP, VFD, to increase speed and ease of use or I wouldn't use it as much. As is it will be relegated to small parts and the odd job cuz you can realistically only take .020-.030" per pass on steel......when it sat in my Grandfather's shop it's big brother was a Monarc that sat in back to do the real turning. But if you have skill, it's like my friends at the track used to say.....I'd rather be known as someone who can drive a slow car fast then a fast car slow!

    I have a thread on it over at the Hobby Machinist Forum linked in one of my lathe part threads here. Even mentioning an Atlas/Craftsman lathe at the Practical Machinist Forum will get you banned......no kidding.

    Best,
    Kelly
     
    Petee716 likes this.
  11. Static balancing is certainly good enough for slow speeds, especially if done with a polished shaft on two straight edges.

    I drive slow cars slow, Kelly.

    Yeah, Jason, why do women comb their hair at a stop light?
     
  12. Jason

    Jason Gold

    Yeah that bunch at practical machinist are quite the bunch. I avoid it at all costs..

    Why Andy? Cuz they can?
     
  13. No, because they don't have anything else to scratch...
     
    Jason likes this.
  14. Jason

    Jason Gold

    LMAO... you're bad! I like it!
     
  15. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    dennis, Fulmen and Mark's castings like this.
  16. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Got the pulleys installed. Both pulley combinations tension the same and it seems to run nicely. I’m going to call this one a wrap.

    27 Installed.JPG

    Best,
    Kelly
     
    Michael, Tobho Mott, Mach and 3 others like this.
  17. Billy Elmore

    Billy Elmore Silver

    Nice job Kelly!
     
  18. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Thanks Billy and for the likes guys......tools making tools!

    Best,
    Kelly
     
  19. dennis

    dennis Silver

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