Lathe belt splicing

Discussion in 'Horological Tools' started by bkerr, Jul 21, 2012.

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  1. bkerr

    bkerr Registered User
    NAWCC Member

    Nov 29, 2007
    1,231
    1
    38
    Male
    Sales & Marketing Manager
    Canal Fulton,OH
    Country Flag:
    Region Flag:
    I am finishing up my new (new to me) Levin 8mm lathe. Things are comming together well and it is now mounted on a bench and the motor is in place.

    I need to get a belt and I tried those green belts that you use a hot razor blade to make the splice. The belt material works well but I don't have three hands so here is what I came up with to make a good (easy) splice job.

    The concept is that the belt is held on the left side (clamped) and positioned half way in the slot. The right side is snug but the belt can slide with a little pressure applied. Center the ends in the slot, get the hot blade ready and while the blade is in position slight pressure can be applied to the splice and can be continued when the blade is out and the material is still soft until it firms up. Remove the four screws, trim the flashing from the splice and now the belt is ready to use. Well, that is the concept and I'll let you know how well it works later today.

    If this is not the right place to post please fell free to move to the proper place. Thanks
     

    Attached Files:

  2. bkerr

    bkerr Registered User
    NAWCC Member

    Nov 29, 2007
    1,231
    1
    38
    Male
    Sales & Marketing Manager
    Canal Fulton,OH
    Country Flag:
    Region Flag:
    Well the belt is now on the lathe. Tool worked good but, I found out that I need to make the slot a little deeper to allow the heated blade to pass all the way thru the belting material. I still ended up putting the tool in a bench vise as well.
     
  3. Ron P

    Ron P Registered User

    Jan 19, 2010
    51
    0
    6
    IT Manager
    Utrecht, Netherlands
    Country Flag:
    Nice method.
     
  4. Max Phillips

    Max Phillips Registered User

    Sep 12, 2011
    174
    1
    0
    Software Engineer
    Barrington, NH
    Country Flag:
    Region Flag:
    Very nice, thanks for sharing! What material did you use for that tool?
     
  5. cazboy

    cazboy Registered User

    Apr 27, 2006
    1,106
    1
    0
    Retired!
    Prescott Valley, Arizona
    Country Flag:
    Region Flag:
    #5 cazboy, Jul 22, 2012
    Last edited: Jul 22, 2012
    Well done sir! Your shop-made tool seems well made and the principle seems sound. If I may share, I use a simpler but very effective method in my shop. I use one of those "third hand" things that has a base and two alligator clips articulated with adjustable linkages. I place the already-cut green belting in the clips and adjust until the two cut ends meet perfectly. Then I tighten down on one of the clip's linkage so it won't move (or resists moving), and loosen the other one so that it's firm but moveable. Then I double check the belting to make sure the ends meet. Then I just spread the loose arm so the belt's tips are about 5/8" or 3/4" apart - and I just hold a Bic lighter between the tips. If the tips are too close together, they'll catch fire, but if they're just right they will heat up and begin to melt without igniting. Once I can see both tips begin to melt, I remove the lighter and move the loose arm back where it was - and the tips usually still meet in the middle. You have a few moments before the belting cools so you can adjust up/down or back/forth, but once you're happy with the joint just walk away and come back later to razor the excess away. It works great for me.

    EDIT: I forgot to mention I keep a fire extinguisher and smoke alarm in my shop at all times, but I've never had any problems because I'm pretty careful - more like paranoid! :cyclops:
     
  6. bkerr

    bkerr Registered User
    NAWCC Member

    Nov 29, 2007
    1,231
    1
    38
    Male
    Sales & Marketing Manager
    Canal Fulton,OH
    Country Flag:
    Region Flag:
    The material is aluminum (6061 T6) that is very common and easy to source. I have been reading about engine turning or jeweling recently and have another project that I posted that I would like to jewel it. The authorities all state that the material to be jeweled shold have no defects. This piece was sanded with 800 grit wet / dry (wet w/ soap) and then buffed on a cotton wheel. It really came out like a chrome finish. To get a sense of scale th length is 3" and the screws are 3 -56. It was all machined from one block of material. I did cut the material in half withmy bandsaw and then on the mill with a fly cutter. While I had things set up I idecided to make a duplicate. Below is a picture of the jeweled and finished product.

    Doug, your method sounds like a very good one too. I have thought about using a soldering iron with a thin flat iron to melt he material. I think I have seen them so I'll be looking. I don't like a flame in the shop but I do use a alcohol burner from time to time (I work on watches too so the the burner comes in handy for setting jewels).

    IMG_1877.jpg

    Now if I could just get the spell checker to work!
     
  7. wefalck

    wefalck Registered User

    Mar 29, 2011
    346
    7
    18
    Male
    Paris
    Country Flag:
    As an add-on: once the the two ends of the belt have been pushed together a sort of doughnut of molten material develops at the joint. I first clip this off with a pair of round scissors and use a coarse grinding wheel to smooth down the joint.

    wefalck
     
  8. bkerr

    bkerr Registered User
    NAWCC Member

    Nov 29, 2007
    1,231
    1
    38
    Male
    Sales & Marketing Manager
    Canal Fulton,OH
    Country Flag:
    Region Flag:
    I used a razor blade to trim up the excess but, thinking about your scissors idea maybe fingernail clippers would work also?

    Thanks!
     
  9. wefalck

    wefalck Registered User

    Mar 29, 2011
    346
    7
    18
    Male
    Paris
    Country Flag:
    Anything that cuts closely would work. Using a coarse grinding wheel afterwards really makes the joint almost invisible, which eliminates vibrations.

    Actually, I think your tool isn't a bad idea, because aligning the two ends carefully also helps to reduce vibrations. However, most of my joints lasted for years, so one doesn't need it that often.

    wefalck
     
  10. bytes2doc

    bytes2doc Registered User
    Donor

    Aug 31, 2009
    95
    0
    6
    Physician
    Tennessee
    Country Flag:
    Region Flag:
    I forget what book I found this technique in but one just secures a knife in a vice which serves as your third hand, heat it. Next touch each side of the knife with the belt and d slide the two ends off each side of the knife simultaneously so the the two end meet together. Works like a charm but you may need to trim off the excess melt. Your design may give more consistent results. Nice work.
     
  11. wefalck

    wefalck Registered User

    Mar 29, 2011
    346
    7
    18
    Male
    Paris
    Country Flag:
    I believe there is a respective illustration in Carlè's book on lathes. Incidentally, not having such a nifty tool, I always used a soldering iron with a Teflon-coated cutting-knife for styrofoam mounted in it. I push the ends onto knife and slide them off when well melted, trying to 'make ends meet' precisely. Trimming off the excess as indicated above.

    wefalck
     
  12. bkerr

    bkerr Registered User
    NAWCC Member

    Nov 29, 2007
    1,231
    1
    38
    Male
    Sales & Marketing Manager
    Canal Fulton,OH
    Country Flag:
    Region Flag:
    I think I am going to get one of these tips for my soldering gun. It makes sense to be able get away from the potential fire hazards. That being said I may not splice another belt for several years but, if I do I will have the tool to do the job. LOL

    pd_6110_100 weller tip.jpg
     
  13. KurtinSA

    KurtinSA Registered User
    NAWCC Member

    Nov 24, 2014
    2,224
    25
    48
    Aerospace Engineer (Ret.)
    San Antonio, TX
    Country Flag:
    Region Flag:
    Figured I'd open an old thread!! I've had to repair my belt now 4-5 times in the past month or so. I found out about the process of heating a piece of metal (putty knife) and sliding the butt ends together. I seem to have done it OK in my book, but each time after only 5 minutes of use, the butt joint slowly opens up. I can't keep using it given that it will open up and who knows what will happen.

    I seem to be missing something. I've been trimming the old ends to get new surfaces. My belt is beginning to shorten and I just noticed that the motor on my Levin lathe is not adjustable. I might have to remove things and open up some slots in order to allow for some adjustment.

    Thanks...Kurt
     
  14. wefalck

    wefalck Registered User

    Mar 29, 2011
    346
    7
    18
    Male
    Paris
    Country Flag:
    What kind of belt material are you using ? I found that the Chinese Polycord imitations aren't as good as the original one (surprise !). While butt-weld on Polycord may have lasted for years, the Chinese stuff seems to come apart every few months and sometime doesn't even weld very well in the first place.
    Make sure you degrease the belt around the joint. The welding works best, if it is really hot, the belt material must be almost running.
     
  15. KurtinSA

    KurtinSA Registered User
    NAWCC Member

    Nov 24, 2014
    2,224
    25
    48
    Aerospace Engineer (Ret.)
    San Antonio, TX
    Country Flag:
    Region Flag:
    The belt is a clear/yellow piece of rubber band. I haven't been trimming back the old butt joint much...just enough to square things up. If I do much more trimming, the belt will get shorter and I have discovered that the motor is fixed in place, so it can't be moved closer to the bed. I'll need to do some surgery to see if I can correct that. :banghead:

    Kurt
     
  16. wefalck

    wefalck Registered User

    Mar 29, 2011
    346
    7
    18
    Male
    Paris
    Country Flag:
    Wouldn't it be simpler to get some new belting ...
     
  17. KurtinSA

    KurtinSA Registered User
    NAWCC Member

    Nov 24, 2014
    2,224
    25
    48
    Aerospace Engineer (Ret.)
    San Antonio, TX
    Country Flag:
    Region Flag:
    I suppose. But won't the headstock of the lathe have to be torn down? I don't have that much experience working on these. This is a used setup I bought last year. The motor has been sort of kludged to fit on the base.

    The downside of all this is that I was three pivots away from finishing a clock and I could start putting it back together. I need to fix something and/or order a new belt. All which shuts me down on this. Kinda bummed...

    Kurt
     
  18. wefalck

    wefalck Registered User

    Mar 29, 2011
    346
    7
    18
    Male
    Paris
    Country Flag:
    Unless you buy an endless belt, you don't need to tear-down the headstock. That's why there are these fusible belts.
     
  19. KurtinSA

    KurtinSA Registered User
    NAWCC Member

    Nov 24, 2014
    2,224
    25
    48
    Aerospace Engineer (Ret.)
    San Antonio, TX
    Country Flag:
    Region Flag:
    Well my fusing attempts are not working. And since my lathe stand needs some major surgery, I'm back at square 0.

    Kurt
     
  20. Dave Coatsworth

    Dave Coatsworth Super Moderator
    NAWCC Business Donor Sponsor

    Feb 11, 2005
    4,734
    113
    63
    Camarillo, CA
    Country Flag:
    Region Flag:
    You might consider using O-rings. Yes, you do need to disassemble the headstock to install one but, by the time one breaks, it's probably time to tear down and clean the headstock anyway. Sort of serves as a reminder.

    If you are using a lathe that you bought last year and have never cleaned the headstock, I would encourage you to do so. Who knows how long since it has been properly cleaned.
     
  21. dAz57

    dAz57 Registered User

    Dec 7, 2011
    2,008
    25
    48
    watchmaker
    sydney Australia
    Country Flag:
    Region Flag:
  22. KurtinSA

    KurtinSA Registered User
    NAWCC Member

    Nov 24, 2014
    2,224
    25
    48
    Aerospace Engineer (Ret.)
    San Antonio, TX
    Country Flag:
    Region Flag:
    What are sources for o-rings of that size?

    Kurt
     
  23. Dave Coatsworth

    Dave Coatsworth Super Moderator
    NAWCC Business Donor Sponsor

    Feb 11, 2005
    4,734
    113
    63
    Camarillo, CA
    Country Flag:
    Region Flag:
    McMaster-Carr www.mcmaster.com

    I've been using "Buna 70" with good long-lasting results.
     
  24. KurtinSA

    KurtinSA Registered User
    NAWCC Member

    Nov 24, 2014
    2,224
    25
    48
    Aerospace Engineer (Ret.)
    San Antonio, TX
    Country Flag:
    Region Flag:
    Dave -

    What is the "70" you're calling out? Is this the durometer of the rubber? Looks like I'm going to have to order a few dozen as a minimum.

    Kurt
     
  25. Dave Coatsworth

    Dave Coatsworth Super Moderator
    NAWCC Business Donor Sponsor

    Feb 11, 2005
    4,734
    113
    63
    Camarillo, CA
    Country Flag:
    Region Flag:
    Yes, I believe that is the durometer value.
     
  26. Firegriff

    Firegriff Registered User
    NAWCC Member Donor

    Feb 22, 2013
    662
    15
    18
    Male
    Country Flag:
    Has anybody used the spring type belting I have received a couple of them in ebay lot buys are there special ends for them or do you cut them and bend the ends and snap them together??
     
  27. praezis

    praezis Registered User

    Feb 11, 2008
    314
    3
    18
    Germany
    Country Flag:
    Region Flag:
    I made the same experience as Kurt with the knife method (recommended by Bergeon and others): does not last. Since years I just melt both ends in a flame and press together, carefully avoiding a shifted step. The bulge around the joint I cut away. Now the joints last!
    I also tried o-rings, but found they are not endless but also welded - not lasting.

    Frank
     
  28. glenhead

    glenhead Registered User
    NAWCC Member

    Nov 15, 2009
    883
    35
    28
    Telecom Engineer
    Williamson County, Texas
    Country Flag:
    Region Flag:
    They're called "garter springs". Yes, I tried one, and it doesn't work for beans. It slips like mad under even the slightest torque. To answer your other question, though, you bend the ends and loop the resulting hooks together.

    Glen
     
  29. karlmansson

    karlmansson Registered User

    Apr 20, 2013
    2,162
    16
    38
    Doctor
    Linköping, Sweden
    Country Flag:
    I’ve found cutting polymer belts at an angle creates both a better join and a lesser bump when run. Bigger surface area.
     
  30. disciple_dan

    disciple_dan Registered User

    Mar 10, 2016
    22
    0
    1
    Male
    Builder/ Clockmaker
    Plant City, Fl.
    Country Flag:
    Region Flag:
    What about using leather shoe string and stitching the ends together?
     
  31. glenhead

    glenhead Registered User
    NAWCC Member

    Nov 15, 2009
    883
    35
    28
    Telecom Engineer
    Williamson County, Texas
    Country Flag:
    Region Flag:
    I've never tried it, but for a good reason. Unless you could stitch the ends together so there was no difference at all in the surface, you'd have a "bonk" every danged time the joint hit the pulley. On a watchmakers lathe, that kind of thing translates to a huge thumpthumpthump that throws your cutting down the toilet. That's why people are so fanatical about removing the molten globules that result from melting the ends together. I have to admit, welding belts is my least-favorite part of using a watchmaker's lathe. I've tried every technique mentioned here, and the only thing that helps is a large excess of swearing. One of these days I'm going to take the time to rearrange all my mountings to go to o-rings.

    Glen
     
    karlmansson likes this.
  32. disciple_dan

    disciple_dan Registered User

    Mar 10, 2016
    22
    0
    1
    Male
    Builder/ Clockmaker
    Plant City, Fl.
    Country Flag:
    Region Flag:
    Yeah, I just got my first watchmakers lathe and it came with a leather belt. I have never turned it on because I want to tear it down and clean it all first.
    I ordered some belting from China of course so I'll be back to this thread when I get ready to splice my belt.
    Thanks for the help.
    See ya, Danny
     
  33. Hudson

    Hudson Registered User
    NAWCC Member

    Jul 19, 2010
    140
    3
    18
    Retired
    Spicewood
    Country Flag:
    Region Flag:
    part-timer likes this.
  34. sharukh

    sharukh Registered User
    NAWCC Member

    Oct 10, 2011
    299
    5
    18
    Doctor
    Mumbai, India
    Country Flag:
    Danny,

    I'm usually not a China basher (though as an Indian, I can be said to have an ulterior motive) but I would suggest you avoid the chinese made belting. It just doesn't weld well enough, the joint is weak and will separate in a short time. And this is not from lack of trying. I've used all the techniques that have been suggested -- using a hot knife, open flame, roll it on glass etc. I've also ordered from 3 different vendors on that big bad auction site.

    I moved to jointed o-ring material. I stick the ends with CA glue. The joints hold well but I have now started using o-rings. It gives me a reason to dissemble the headstock to clean and lube as well as change the o-ring.

    Sharukh
     
    disciple_dan likes this.
  35. Thomas Hammond

    Thomas Hammond Registered User
    NAWCC Member

    Apr 17, 2010
    34
    1
    8
    No one seems to have mentioned my favorite belt for watchmakers lathes, milling spindles, small drill presses, and the like. After trying pretty much all the other options, I have been using Gates 3M or 5M (the numbers indicate the width in millimeters, and the numbers following the 3M or 5M indicate the circumference, also in millimeters, like 5M500) "Polyflex" vee-belts. I first encountered them on a Taig lathe, where a 3M belt easily handled the power of a 1/6 HP motor. I have them on six different machines in my shop -- two Rivett lathes, Levin 3C lathe and Levin drill press, a Schaublin milling spindle, and a home-made pinion mill (from the Hemingway "kit"), and they are completely trouble-free, lasting for years and years. As with O-rings, you do have to disassemble the headstock to install them, but as has been mentioned, that is a good opportunity to clean and relubricate the bearings.

    They are widely available on eBay, and many bearing shops can obtain them.

    Hope this helps,

    Tom Hammond
     
  36. wefalck

    wefalck Registered User

    Mar 29, 2011
    346
    7
    18
    Male
    Paris
    Country Flag:
    The pulleys on the watchmakers lathes are designed for round belts and to my knowledge the Vs have different angles for the different types of belts. You would have to get a V-belt with just the right angle.

    Another issue I would have with V-belts, though they are mechanically for efficient than round belts, is that they require near perfect alingment between the pulleys. If you use a speed-reducer transmission, it is likely that in certain combinations you will have some off-set. I also use idler pulleys on the milling machines that re-direct the belt at right angles in different planes, which can only be done with round belts.

    I agree with Sharukh comment on the weldability of Chinese-sourced round belts. They are of lower quality than the original green Polycord® belts, as I wrote already earlier, I think. The problem I have is to find a detail source for the belts, as the importers seem to sell only large quanties and with a minimum order value of 70€ or something like this. Would last me a couple of life-times at least ...
     
  37. gmorse

    gmorse Registered User
    NAWCC Member

    Jan 7, 2011
    8,380
    125
    63
    Male
    Retired from Xerox
    Breamore, Hampshire, UK
    Country Flag:
    Region Flag:
    Hi wefalck,

    Tony Griffiths at lathes.co.uk sells all kinds of belts, including genuine Polycord® round belting, by the metre.

    Regards,

    Graham
     
  38. wefalck

    wefalck Registered User

    Mar 29, 2011
    346
    7
    18
    Male
    Paris
    Country Flag:
    Didn't know that Tony was selling also Polycord® belting ... but looking at the prices, I am almost better off getting it whole-sale ...
     
  39. Thomas Hammond

    Thomas Hammond Registered User
    NAWCC Member

    Apr 17, 2010
    34
    1
    8
    Wefalck wrote "The pulleys on the watchmakers lathes are designed for round belts and to my knowledge the Vs have different angles for the different types of belts. You would have to get a V-belt with just the right angle.

    "Another issue I would have with V-belts, though they are mechanically for efficient than round belts, is that they require near perfect alingment between the pulleys. If you use a speed-reducer transmission, it is likely that in certain combinations you will have some off-set. I also use idler pulleys on the milling machines that re-direct the belt at right angles in different planes, which can only be done with round belts."

    I have been using the Gates 3M and 5M belts on my watchmakers lathes for well over 20 years; neither pulley shape nor alignment seems to be an issue. And I have a Gates 5M belt on my Levin drill press, where the drive comes up from the motor on the baseboard, and goes over idlers to reach the spindle pulley. All I can suggest is that anyone who is not satisfied with other belt options try the Gates belts. My guess is you will never go back.

    Tom Hammond
     
    part-timer likes this.
  40. part-timer

    part-timer Registered User

    Jun 27, 2017
    7
    0
    1
    Country Flag:
    ^^^^^ THIS is the answer. I've been using O-rings from this source for years, and I have NEVER had one split.

    I also use the small V-belts referred to by Tom Hammond - they work extremely well. The angle may or may not be ideal, but they just work.
     
  41. kevin h

    kevin h Registered User

    Apr 9, 2015
    237
    27
    28
    Male
    cambridge md
    Country Flag:
    I am glad someone else had trouble with the chinese belts ! I thought it was me , out of desperation I ordered a singer sewing machine belt and have just installed it -it is a little thick but works great , the other option I liked was gmorse's suggestion , they have all kinds of belts . They also have hollow belt with metal butt connectors I would like to try . thanks
     
  42. Firegriff

    Firegriff Registered User
    NAWCC Member Donor

    Feb 22, 2013
    662
    15
    18
    Male
    Country Flag:
    This is what I have been experimenting with for belt splicing took several tries but I finally got a belt to stay connected. 25 watt soldering with changeable tips and a hobby knife made for cutting plastic made for soldering irons both bought at "Hobby Lobby".

    Belt splicer.JPG
     
  43. disciple_dan

    disciple_dan Registered User

    Mar 10, 2016
    22
    0
    1
    Male
    Builder/ Clockmaker
    Plant City, Fl.
    Country Flag:
    Region Flag:
    Sharukh[/QUOTE]

    [QUOTE=I moved to jointed o-ring material. I stick the ends with CA glue. The joints hold well but I have now started using o-rings. It gives me a reason to dissemble the headstock to clean and lube as well as change the o-ring[/QUOTE]
    Thanks for the info. I have a lot to learn and I appreciate all your help. Danny
     
  44. Dushan Grujich

    Dushan Grujich Registered User

    Jun 20, 2003
    505
    4
    18
    Male
    Watchmaker
    Bondi
    Country Flag:
    Region Flag:
    Quite right!

    According to the Levin, the US maker of high precision watch and instrument maker's lathes the V-groove angle for a round lathe belt should be 53 degrees of arc. At the time this would have been related to the round leather belts, however, nothing should change when considering use of textured polyurethane belt.

    ?temp_hash=2139a2a6455e48edda0ce44278fc0fa8.jpg

    Cheers,

    Dushan

    Pulley Grooves Angle.jpg
     
    disciple_dan likes this.
  45. wefalck

    wefalck Registered User

    Mar 29, 2011
    346
    7
    18
    Male
    Paris
    Country Flag:
    Checked my Lorch, Schmidt & Co. and Wolf, Jahn & Co. lathes and the angle is 70°, while on the WJ&Co. and Dixi millers the angle is 60° ... remember now that I cut some idler pulleys for the millers with a 60°-threading tool ...
     
  46. Firegriff

    Firegriff Registered User
    NAWCC Member Donor

    Feb 22, 2013
    662
    15
    18
    Male
    Country Flag:
    The big thing with the soldering iron with a exacto blade they are very sharp and i did jab my arm on it bled like a stuck pig.
     
  47. Coalbuster

    Coalbuster Registered User

    Aug 22, 2017
    28
    3
    3
    Male
    Retired
    Country Flag:
    Region Flag:
    I noticed on the McMaster site that their fusible, textured 4mm polyurethane belting specs a minimum pulley size of 36mm. This is smaller than the pulley on my drive motor and a lot of motors I see online. Could this be the cause of the premature belt failure? The smooth belting doesn't have a minimum pulley size.
     
  48. wefalck

    wefalck Registered User

    Mar 29, 2011
    346
    7
    18
    Male
    Paris
    Country Flag:
    I gather you meant that your motor-pulley is smaller than the minimum diameter specified ...

    There are two effects:

    - if the pulley is smaller, the belt my be too stiff to lay on the pulley and then you grip and transmission power

    - if you force the belt around, you are tightening it too much and its internal working will damage its structure with time (apart from not being good for the pulley/lathe bearings

    This essentially applies to any type of round belt. Some belts may be softer than others and therefore would accomodate smaller pulleys.
     
  49. Coalbuster

    Coalbuster Registered User

    Aug 22, 2017
    28
    3
    3
    Male
    Retired
    Country Flag:
    Region Flag:
    Yes, I meant that my pulley and maybe most motor pulleys were smaller than the minimum recommended diameter and whether turning a textured belt around a tighter diameter than specified leads to weld failure.
     

Share This Page