New lathe project

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

  1. Robert

    Robert Silver

  2. Petee716

    Petee716 Gold Banner Member

    Thanks for that link Robert. That was quite a write up. The poster is quite an ambitious fellow and did a really nice job on that machine. All or nothing I'd guess. The independent power feed really got my attention. The former owner's machine drive solution with the 3-speed transmission was really quite ingenious although it was poo-poo'd as being Appellation. I guess the wiper motor solution was...Silicon Valley?
    You're right though, there's some real food for thought there. My goal at this point is to get the machine back into running condition and clean enough to not cause further issues. Anything beyond that I'll take as it comes (although that independent feed motor interests me quite a bit).
    I've made some progress with the position of the countershaft mounting by adding another 6" of angle iron to the mounting brackets so I could elevate the cone to an acceptable level to keep the belt from rubbing. (See the belt photo in my post#54.)
    I've got my feelers out for a treadmill.
    I made a pretty encouraging find regarding my compound slide. It appears that the Craftsman/Atlas 12" cross slide has a similar mounting configuration to mine. So if I get a whole Atlas cross slide assembly I can open the hole in the base a bit and it should fit right on. Their mounting hole is 1.5 inches and mine is 1.75 inches. The holding profile on my machine's round cross slide mount is a simple wide groove as opposed to the 60 degree dovetail found on South Bends and others (see photo in my post#33) , so I believe it's within my capabilities to successfully make the modification. The overall height of the assembly may be an issue so I have some further research to do. Anyone with a 12" atlas that could lend some specs to me would be greatly appreciated.
    My other alternatives would be to cast an iron slide to fit my base, or to machine from a block of steel or CI, both of which I've never done but am not afraid to try, but I think the needed accuracy of the mating surfaces would be a bit more than I can handle. So in this case I think modifying a factory made assembly is the way to go.

    Pete

    Edit: should have said "So if I get a whole Atlas compound slide assembly..."
     
    Last edited: Jul 21, 2018
  3. Petee716

    Petee716 Gold Banner Member

    image.jpeg
    The patient has arrived...
    It starts, stops, and accelerates as it should. Any tips or pics on how I should harness this to the lathe? I'm not sure if the countershaft bearings are really designed to run any faster than 1750rpm so I'm wondering if I should remove the countershaft and just run the flat belt directly from the DC motor to the smallest pulley on the spindle and call it done.

    Pete
     
  4. There's a commodity KB brand 180V speed controller unit that show up on Ebay all the time. They have all the nice features you would want in a DC speed control. Personally I think a small three phase motor/VFD combo will be a better option if you have the budget for it. The treadmill motors are built to a low price point and I have seen problems from shorted windings, shorted commutators from carbon dust and other problems. If you can score a nice 90 VDC Baldor motor for cheap then it might all be worthwhile.

    These are available in 120V and 240 V versions:

    https://www.ebay.com.au/itm/PENTA-KB-POWER-KBIC-120-SCR-SOLID-STATE-VARIABLE-SPEED-DC-MOTOR-CONTROL/292008167866?hash=item43fd0b09ba:g:AtgAAOSwA3dYhkga&_sacat=0&_nkw=KB+speed+control&_from=R40&rt=nc&_trksid=m570.l1313
     
  5. Petee716

    Petee716 Gold Banner Member

    Yeah I think I'm overthinking this deal. I have the 180VDC that I won't be confident in until I spend $150 on a the proper drive, and the treadmill motor that just doesn't seem like the right gun for this particular battle. But I also have a 1-1/2hp 120VAC motor just sitting in a corner collecting dust. Hmm. The answer seems pretty clear.
    I found a nicely restored Seneca Falls lathe here that shows the pulley ratios the restorer used. I have no idea how accurate they are to original recommendations, but they seem reasonable.
    http://www.lathes.co.uk/senecafalls2/
     
  6. Greg

    Greg Copper

    That lathe is a good buy . There is a lot of work to do , but be patient and be careful as the cast iron that was used in making this machine is very good but will break easy .
    The other thing with these lathes is the bed is a soft and if used in the area near the chuck it will be worn.
    This means grinding and scraping the bed.
    I am a fitter and turner and a marine engineer If I can help you out with advise I will help you
    I have other experiences also .
    Welding cast iron can be very tricky but I may be able to advise you with this process
    Good luck with the project.
    I have no experience in casting but hope to learn from this forum
    Greg
     
  7. Petee716

    Petee716 Gold Banner Member

    Welcome to the forum Greg and thanks for the offer of support. There's plenty of help and encouragement here and every bit is appreciated.
    I haven't made any further progress on the lathe as time has been short as of late. House, family, work, etc. I just got a brand new asphalt driveway put in a few weeks ago as well (happy dance!!) so lots of backfilling and landscape stuff too. Boy I'm sure not going to miss plowing snow over millings this winter.

    I decided to mount my spare 1hp 110V motor instead of the treadmill just to keep the project moving. That'll be enough power to get me going and may well be enough moving forward. I can change the motor voltage to 240v if I want. Would there be any advantage?

    I had a step pulley in my parts pile which I had to open up on my South Bend 9 to fit the 5/8 shaft of the new motor. I cut a keyway into it by mounting it in the 4-jaw chuck, locking with back gears, and moving a high speed tool ground to the right profile through repeatedly. When it was working it peeled a nice chip but it took a long time and I restarted a couple of times. Between the material (zamak), probably the tool profile (I'm a total novice), and the light duty nature of my little lathe, once it started to bite it didn't want to move. I ended up with a nice keyway but it took an awfully long time. I ended up getting a good final fit with a file.

    I've been debating on whether to just mill a new tool holder/compound out of steel and dispense with the slide action, but an experienced machinist friend has convinced me to make it from cast. He said he would help with the dovetails. He made a statement much in keeping with what Mark's castings has been implying, that protecting the spindle bearings is the most important thing and anything downstream should be breakable within reason.. So the thin design of the (broken) tool holder mount makes a little more sense.
    It looks like I will indeed be casting some iron. I've made a floating appointment at my buddy's junkyard and got a few lbs of ferrosilicon from BCS so it looks like I'm on my way!

    Pete
     
    Tobho Mott likes this.
  8. Tobho Mott

    Tobho Mott Gold Banner Member

    Oooohh, casting iron! This ought to be interesting!

    Jeff
     
  9. Great project!

    The only advantage to going to 240v is half the amperage if you have any voltage dip when starting on 120v. With 1 hp I doubt you'll see any problem unless you have a long run of 14 ga wire. 1 hp may very well power the lathe nicely and is also a safety valve against breakage on the other end. I don't mind stalling out my 9" South Bend.
     
  10. Melterskelter

    Melterskelter Gold Banner Member

    On the other hand.....:rolleyes:

    I think that lathe looks like it can handle a fair bit more than 1 HP. One horse will do you fine for turning smallish parts. But, as the turned diameter gets up around 3 or 4 inches in steel, you will appreciate more power to peel off a larger chip. So, I think the idea of hooking up an available 1HP motor is great to get started. But set aside a coffee can to slowly stuff with ones until you can buy a 3HP 3-phase and a VFD to go with it. The soft start, reversing, and on-the-fly variable speed afforded by the VFD are so sweet. I am running a 3 VFD's in my shop and love them. I can make some brand recommendations if you are interested. All run off 110 or 220 60 cycle. I would hate to go back to constantly dealing with step pulleys and hard starts.

    I am only guessing about the 3 HP sizing, of course. But that looks about right for that lathe.

    Denis
     
  11. Greg

    Greg Copper

    A 3 Hp motor . This depends weather you want to rip into the turning or just Machining.
    Also this lathe would have used High speed tool steel . If you use carbide tools then this could be a mistake as the speed is higher and the load is greater.
    Also I beleave the head shaft bearings would be brass or white mettle.
    The bearings can not handle high loads and fast speeds .
    This should take into consideration the above befor punching a mother
     
    joe yard likes this.
  12. Melterskelter

    Melterskelter Gold Banner Member

    Hard to say the exact right power. If turning a 6 inch part at 100 SFM you would be turning at 150 RPM. HSS likes about 100 SFM and a healthy chip. One horse won't allow much of a cut and, if there is much to remove, will take forever as you take 20 thou cuts. (Carbide might be three times the RPM and probably a little less chip than HSS.) So, while saving up for a VFD and 3-phase of whatever power, it may become more apparent what the ideal motor size might be. Maybe that will be 1 HP or maybe more. Whatever size, a VFD and 3-phase is mighty nice.

    I just hope you get a lot of satisfaction from fixing up that lathe and enjoyment using it to its fullest. I'll be following and vicariously cheering you on.

    Denis
     
  13. Petee716

    Petee716 Gold Banner Member

    I was planning to put the 1 horse on just to at least get the wheels turning. Although this one may not have originally come with a motor I think the ones that did had 1-1/2hp. I'll be looking for a top speed of about 700 rpm. There's a pretty nice write up http://www.lathes.co.uk/senecafalls/ that speaks of the spindle running in the cast iron headstock so it'll have to be fairly low speed operation so it will probably see mostly HS tooling. They made these lathe with foot treadles too!
    I have a couple of VFDs running 3ph motors on my table saw and mill, mostly for purposes of phase conversion, but I use a pot on the mill. Very convenient and pretty cheap. They're rated for 3hp but I think my 2hp table saw motor is underpowered. Probably a function of "cheap".

    Pete
     
  14. Melterskelter

    Melterskelter Gold Banner Member

    Ya, I really like the convenience and good service I have gotten from Automation Direct on their VFD's. I like the fact that they actually will get on the line and talk (in English as a first language) about any questions or problems you may have and their printed and nicely bound documentation/user manuals are the exception nowadays. The removable remote keypad control is a huge plus and is much simpler than setting up your own remote switching and pot to control the VFD. (I did my own once at no real cost saving and spent several hours time when I could have just plugged in the AD control unit and been ready to go in a minute or two. Never again will I do it from scratch...)

    Denis
     
  15. Keep in mind also that horsepower is the rate of work done, so if you have a 3 Hp motor and run it at half speed, it becomes a 1.5 Hp motor, the rate of work done is halved, i.e. horsepower. So if you fit the larger 3Hp motor it will still have usable power at lower RPM's. It's the same reason AC motors of a given horsepower get larger as the rated RPM drops.
     
  16. Petee716

    Petee716 Gold Banner Member

    I got distracted and this is what happens! I bought these items locally on EBay. They came from Buffalo State University, the same place I bought my mill, drillpress, and table saw a few years ago. The saw is shown in the midst of disassembly for a good cleanup and oil change. It's a mid-70s model Delta Rockwell 14" metal/wood saw. The grinder needs a new cord and is missing the right hand tool rest (another casting job).
    The saw came with the factory motor: 1/2HP 3ph which I removed. I don't want to buy another VFD for it and its position in the shop won't be conducive to sharing power with my other 3ph equipment. So the 1Hp motor I was going to put on the lathe has been diverted to the saw. I changed the 1HP over to 230V so I could still use the same contactor setup that came on the saw. I'll post the pics of both machines once I have the both back together and running.
    So the question is, in light of the previous discussion here, would the 1/2HP 3ph be too small to mount to the lathe? The power is available because I plan to share the VFD from the table saw which is right next to it, but will the upgrade in phase make it a viable option, or am I reaching a bit too far? The original lathe was offered with a 3/4 motor back in the day just for reference.




    image.jpeg image.jpeg

    Pete
     
  17. Melterskelter

    Melterskelter Gold Banner Member

    "So the question is, in light of the previous discussion here, would the 1/2HP 3ph be too small to mount to the lathe?"
    Yes. Buy a bigger motor. You can always use it at a lower power than its nameplate amps, but you can't use a low power motor effectively at higher than its rated amps. I can not imagine a time when you find yourself wishing for a lower power motor, but I think with a 1/2 horse motor you are going to be needing more power a lot of the time. 6 months from now you will have forgotten the money you forked over for the larger motor, but with a smaller motor you will still be wishing you had more power. ;-)

    Denis
     
    Last edited: Sep 9, 2018
  18. I would put the 1/2 horse motor you already have right on and then figure out for yourself whether it is worth putting more money into it. Depending on your use you may find 1/2 hp adequate. Not your only lathe is it?
     
  19. Looks like Buffalo State University is divesting itself of all those nasty dangerous tools: a local university over here banned maintenance staff from using a drill press until they could provide qualifications to prove they could operate one. My milling machine came from a technical college: I visited the campus to look for a manual for it and found the trades section had been shut down and the buildings are used for training hair dressers and child care workers..... /Rant off.

    In answer to your question about motor sizing: motors vary a lot. Older motors tended to be greatly underrated, modern ones not nearly so much as it allows for greater efficiency and lower cost. A locally made brand: Brooks Crompton Parkinson, used to wind the exact same motor: a single phase cap start, cap run motor and sold it as a 1Hp, 2Hp and 3Hp motor just by varying the size of the integral overload breaker.
    They stopped doing that sometime in the 1980-1990's and people found the identically rated replacement motor kept popping it's breaker as their older motor was actually running way past it's rated Hp. My old 1950's-1960's lathe has a 5Hp motor built in a frame more suited to a 10Hp motor, I'm sure it could provide way past 5Hp for short periods of time.

    You should fit a 1/2Hp single phase motor or a 1Hp three phase ( to allow 1/2Hp at low speeds on a VFD ). Motors are easy enough to come by at the scrap yard and refit with some new bearings to run like new and you'll need a few over the years for various projects anyway.
     
    Last edited: Sep 9, 2018
  20. Petee716

    Petee716 Gold Banner Member

    I finally got a motor on this beast and made my first chips today. Single direction only for now. I tested on aluminum and it ran fine. I chucked up some 4140 rod and the compromised compound slide gave out almost right away. So we wait till it's warm enough to cast some iron.


    image.jpeg

    Pete
     
    Mark's castings likes this.

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