New lathe project

Discussion in 'Other metal working projects' started by Petee716, Jun 27, 2018.

  1. dtsh

    dtsh Silver

    Looking good.
    As for HP, your biggest limitation will be the belt; if you bite into anything deep, it will slip. When my belt broke last year I abandoned the leather for a serpentine belt and have been very happy with it. To get a serpentine belt on, some folks cut the belt then superglue it back together, but removing the spindle to slip the belt on/off is so simple with these.
     
  2. Petee716

    Petee716 Gold Banner Member

    I took lathe for a test drive after getting the compound put back on it. The compound works well
    I had extended the frame that the motor and countershaft are mounted to because the belt was dragging on the headstock (post #80) and I needed to elevate the countershaft. The thing was bouncing like crazy so I made an overcenter tensioner for it.

    image.jpeg image.jpeg image.jpeg

    Works pretty good. All made from bits and pieces I had laying around. Just had to buy a couple retaining clips and thrust washers.

    One of my friends dropped me off a bunch of assorted steel shaft drops. Between 1-1/8 and 1-3/4 diameter. Varies from 3 to 6" in length. It's very handy for small jobs. I think it 4140 or similar. It's not hardened, but it's still hard. I had a tough time tapping this 1/2-13 thread with my Craftsman beater tap. I wanted to show the alignment feature on my tap wrench. It's super handy for straight starts and in this particular case I left it on once the thread was started and was very handy for supporting the end while I muscled the threads in.

    image.jpeg




    I also discovered a couple of issues behind the apron. The clutch slips when trying to run the cross feed. It doesn't slip when I run the longitudinal feed, but it skips on the worn out bronze worm. Those components can be seen in post#36. My friend gave me a cylinder of bearing bronze to cut the new worm and he shot blasted the mating parts of the clutch. We'll see how that works out, but meanwhile I turned a mandrel between centers on my South Bend and mounted an aluminum blank to test out the tool I ground for the job. 5 TPI acme thread. I'll post a picture of the tool and my test results tomorrow. I drilled and tapped the mandrel for a set screw that sits just high enough to interfere in order to keep the part from starting to move. It's a good press fit between the parts but I also used red loctite. Hopefully I'll be able to get the worm off the shaft! Well, that's why we practice I guess.

    image.jpeg



    Pete
     
    oldironfarmer and Tobho Mott like this.
  3. Melterskelter

    Melterskelter Gold Banner Member

    Pete,

    I use a very similar tap wrench setup on my lathe. When you say “muscled in” does that mean you cut the thread with the spindle stationary? Or did you hold onto the wrenches bar while the spindle turned? I do the latter being careful to have no pinch potential of my hand. I usually drill a hole a bit larger than the 75% hole recommended in the various tap drill charts. Except in the most demanding circumstances a 65 % hole works fine and is a lot easier to tap.

    Good work!

    Denis
     
  4. Petee716

    Petee716 Gold Banner Member

    I've never tapped under power. Too much of a scaredy-cat. With the resistance I was getting I think the tap would have surely broken. I locked up the back gear. Given the application for the part in hindsight a slightly larger hole and therefore weaker thread would have been fine but it didn't occur to me. Most of my tapping experience is in the #10 to 3/8 range where a 64th a big jump. I do have a bit of a stick-to-the-chart, better-safe-than-sorry approach to everything that could probably use some tempering. I guess being stuck in that mentality can be like driving with my brakes on. (My employees surely think so! Lol.) I think the quality of the tap made a difference though. Although my 1/2"-13 tap has seen little use, its from an old craftsman set I bought as NOS on eBay years ago and is probably better used for chasing than cutting. I have sets of taper, plug, and bottoming taps that I bought from McMaster Carr but only in 1/4 and 5/16" ($) and you can tell the difference straight away from a craftsman or Irwin. Now that I'm thinking of it I broke a 10-24 yesterday tapping for that set screw shown above so I should probably spring for a set of those as well as a new drill bit. Fortunately I had cut just enough thread and the tap broke up high so it was easy to remove.
    Although those round steel drops I described above drill and turn ok as is, I should probably anneal one to see if it makes a difference in tapping.

    Pete
     
  5. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Way to go bringing your lathe back online Petee.....good to see it cutting chips.

    Best,
    Kelly
     
  6. Melterskelter

    Melterskelter Gold Banner Member

    I long resisted buying “premium” taps like those made by Guhring. But for common sizes I am gradually springing for them. For power tapping which I routinely do on my lathe and mill, you definitely want spiral point taps. Ground premium taps are worth the price. I find them on eBay for twice the price of the lower quality ones. They cut easier, leave a shiny thread, and last a long time. On the rare occasion I need to hand tap, the spiral points are great.

    I think very few manufacturers would drill for a 75 % thread unless specifically called out as such on a print. I am not recall the last time a I had a thread fail. Must be many many years ago.

    Denis
     
  7. Jason

    Jason Gold

    I have terrible luck with Irwin from blowes. Too brittle. Now I pony up the money at a local tool shop. I'm finding they are allowing me to grow some thick hair on my balls. Worth the 25bucks a 1/2"-13 costs.
     
    joe yard likes this.
  8. You guys are going to make me buy expensive taps, aren't you!:cool:
     
  9. Petee716

    Petee716 Gold Banner Member

    I've made some progress on the new worm project described a couple of posts above. I made a mess of my first aluminum trial. I miscued with the thread dial but I've got that sorted now. I'm still a threading neophyte so I give myself a pass! I cast a new blank out of aluminum, successfully threaded it, and cut the key way notches with a broach ground from a broken tap.


    The broaching procedure also gave me a good reason to make a new quill handle. I never had one with this machine and this project would have been impossible without it.
    Oh yeah, I almost forgot! I reassembled the part into the lathe and it fit and worked perfectly! Now I have to cast a bronze one and do it again for realz.
     

    Attached Files:

  10. Jason

    Jason Gold

    You know why they are expensive? Because they are worth it!:p
     
  11. Melterskelter

    Melterskelter Gold Banner Member

    I really like McMaster Carr as a source for taps. American made almost always and of very good quality. I also keep my eyes open for Emuge taps on Amazon---they simply cut better. Even I can tell the difference. I recently made a bunch of heavy duty Tee-an nuts from 4140 steel that I hardened and tempered. The 5/8-11 Emuge cut the threads shiny and smoothly an inch deep on my mill. No way would that job have gone smoothly with a crappy tap. The Emuge quickly paid for itself in time and trouble saved.

    Denis
     
  12. Jason

    Jason Gold

    I wish I knew the brand of the taps I get from my local supply house. Somehow cutting out the middle man on this one seems kinda wrong. They've saved my ass many times so I just pay the money and remember it helps keep local guys working. (something of a rarity these days!)

    I'm seeing an issue country wide as I travel. Many many businesses are closing, closed or seriously limiting service because they all tell me the same thing. Their employees aren't coming back to work because they are making more money sitting on their duffs at home collecting a check ON MY TAX DOLLARS! WTF!:mad::mad: Case in point, a BBQ joint I frequent in Louisiana is now closed so I have to drive 30mins to their second store. I asked them whats going on and BINGO, lazy asses don't wanna work. I know if my butt is on the ground for more than a week, I'm going apeshit. Despite someone's opinion here, I get paid well and like to earn it demonstrating my skill as competent aviator. You have to have balls of steel tempered with a chicken shit heart.;)
     
    oldironfarmer likes this.
  13. Peedee

    Peedee Silver

    One thing I learned from my dealings with China, Malaysia and Taiwan was that a reply of 'Yes' just meant they had heard what you have said. So when it came to suppliers the fact you had specifically said I want virgin ABS, they said yes and made it with re-ground shite. The same goes for steels. I really wish we had a good supplier of tool steels here now that didn't cost the earth but I guess it's becoming more and more of a niche market.

    As for aviation stuff, don't start me on the price of an sp13 4BA washer............... Sorry, as you were ;)
     
    Jason likes this.
  14. Petee716

    Petee716 Gold Banner Member

    Since the aluminum part and thread-cutting test worked out, I cast a couple of turning blanks in bronze to do the real deal. I just used a 5 inch length of PVC packed with greensand for the pattern. I rammed the drag solid in greensand and bedded the pattern. Actually, I dug a cavity out of the greensand and filled it with a layer of petrobond and then bedded the pattern. Before filling the cope I faced the pattern with Petrobond as well. It worked out really well for what I was trying to do (prevent the sand sticking to my turning blank. I didn't care so much about the sprue and gating). At shakeout, the burnt petrobond just ran out of the otherwise hardened greensand, so no mixing of the different sands.

    Pete
     

    Attached Files:

  15. Petee716

    Petee716 Gold Banner Member

    Finished, fitted, and functional!
    20210529_182700.jpg

    Onward.
    Hey Jeff, your tip for placing the photo worked great!

    Pete
     
  16. Clay

    Clay Copper

    Nice work, that's what it is all about.
     
    Jason likes this.
  17. Melterskelter

    Melterskelter Gold Banner Member

    Cutting acme threads isn’t the easiest task. Well done!

    Denis
     
  18. Tobho Mott

    Tobho Mott Gold Banner Member

    Looks great!
     

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