Results 1 to 12 of 12

Thread: Pulley Turning Tool?

  1. #1
    Registered thudson's Avatar
    Join Date
    Apr 2005
    Location
    USA
    Posts
    91
    Downloads
    0
    Uploads
    0

    Default Pulley Turning Tool?

    Okay, it's been over twenty years since I've done any machining, but I spent most of yesterday turning aluminum 7075 round stock down for the mini-mill belt conversion pulleys on my new little 7x10, and I had a blast doing it.

    Thought I might have a bit of learning to do with speeds and feeds, but I guess it's like riding a bike, you never forget something when it 'feels' right and the chips are coming off properly.

    Now I am trying to remember how to make pulleys. It seems we had this tool where the cutter was almost ninety degrees to the shank, and you would first cut the depth of the v in the center of the groove, and then angle the compound slide and cut the angles.

    But I can't seem conjure up enough google-fu to find this tool name or any venders of it.

    Does it have a name, or does someone have an alternate cutting method?

    Similar Threads:


  2. #2
    Registered
    Join Date
    Jan 2010
    Location
    usa
    Posts
    485
    Downloads
    0
    Uploads
    0

    Default

    I use a tool bit ground into a kind of short cut-off tool shape. I don't have a digital camera or I would post a photo. I'll try to describe it the best I can.

    1. I take a regular high speed steel bit, and grind a front relief and square-up the end at same time.

    2. Grind both sides of the bit giving it side relief and at the same time making it thinner at the back than the front. Kind of like the shape of a dovetail joint in wood working.
    the length of the side grind should be a little longer than the depth of your groove.
    The width at front should bee a little narrower than the bottom of the groove.

    3. Then I put a little top grind on it. Just like a sweeping hollow grind, to get chips flowing while cutting.

    Then do like you said plunge straight in to the depth, angle compound and cut each side to correct width as shown in Machinery's Handbook.

    Hope this makes sense to you.

    cary



  3. #3
    Registered thudson's Avatar
    Join Date
    Apr 2005
    Location
    USA
    Posts
    91
    Downloads
    0
    Uploads
    0

    Default

    Thanks, that makes perfect sense.



  4. #4
    Registered thudson's Avatar
    Join Date
    Apr 2005
    Location
    USA
    Posts
    91
    Downloads
    0
    Uploads
    0

    Default

    Just a followup for anyone else needing the info, I found this PDF which shows the tool I remember. But if you look at the cutting portion it is ground just like packrat explained:

    http://www.green-trust.org/junkyardp...eltPulleys.pdf



  5. #5
    Registered
    Join Date
    Jan 2010
    Location
    usa
    Posts
    485
    Downloads
    0
    Uploads
    0

    Default

    That looks like a forged tool blank they used. Better not let the "experts" on this forum see this. To "them" if you don't use carbide insert tooling, you can't call yourself a machinist!

    Glad to have been some help to you.

    cary



  6. #6
    Registered knudsen's Avatar
    Join Date
    Feb 2010
    Location
    USA
    Posts
    709
    Downloads
    0
    Uploads
    0

    Default

    I thunk it was HSS you needed to cut with to call yourself a machinist

    I saved that pdf. Might not be rocket surgery, but sure seems a lot easier to setup and cut an accurate angle than to measure one and reverse engineer something like a "V" pulley. Thanks for posting that.



  7. #7
    Registered thudson's Avatar
    Join Date
    Apr 2005
    Location
    USA
    Posts
    91
    Downloads
    0
    Uploads
    0

    Default

    So I ground my first HSS lathe tool and cut the smaller diameter of a double pulley (Spindle pulley for X2 belt drive conversion).

    I really liked the outcome, but had some difficulty with the side nearest the larger diameter pulley. Had to take the shield over the tool holder off.

    Lessons learned:

    - I wish I had a better way to grind lathe tools on my grinder, but I'm not ready to build a Tinker or Quorn, thinking of something simpler to set compound angles. I have one of these:
    http://www.harborfreight.com/cpi/cta...emnumber=35098

    - The compound on the 7x really sucks.

    [full on rant mode]
    - I fail to see the logic in mixing fastener standards for accessories on a machine. Every fastener on this lathe is metric, except for the A2Z QCTP tool holders which use 3/32 allen. I started my career at a company that was mostly metric (Michelin Tire), but they had a rule: Metric fasteners on metric machines and SAE fasteners on SAE machines. NEVER MIX.

    Now I have to keep two sets of allen wrenches near the machine, which also means double the guessing of the size. Unfortunately, I never mastered the skill of my father "Hand me the 5/16ths."
    [Rant mode off]

    Last edited by thudson; 04-25-2010 at 12:39 AM. Reason: clarification


  8. #8
    Registered knudsen's Avatar
    Join Date
    Feb 2010
    Location
    USA
    Posts
    709
    Downloads
    0
    Uploads
    0

    Default

    I've done all my grinding on a pedestal grinder. Actually on one or two of the 5 or 6 I have (I know, I have a grinder problem). There is some good info in the 3rd and 4th threads here: http://www.chaski.org/homemachinist/...0c259f4d2e589a

    I have a grinder like yours, but it's yellow I just use the slow speed wheel for knives on that one, never used the dry wheel yet. Ironically, the cheapest, smallest, $30 HF baby grinder is my favorite for finishing HSS: http://www.harborfreight.com/cpi/cta...emnumber=43533 I never used the flex shaft and don't even know where it is. That fiber wheel is great for deburring, but not sharpening.

    The compound is the weak point on the 7x. I've got a Tormac QCTP and it's metric. If it really bugs you, maybe drill/tap for metric? It would bug me. My pet peeve is go to take something apart and there's 9 Philips and one slotted screw I have to admit, though, I've used inch screws on stuff I make for my metric mill and lathe. Soooo much cheaper and I have the stuff on hand.



  9. #9
    Registered
    Join Date
    Jan 2010
    Location
    usa
    Posts
    485
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by knudsen View Post
    I thunk it was HSS you needed to cut with to call yourself a machinist

    I saved that pdf. Might not be rocket surgery, but sure seems a lot easier to setup and cut an accurate angle than to measure one and reverse engineer something like a "V" pulley. Thanks for posting that.
    You would be surprised at the experts that seem to think that for cutting you need the latest and newest to do a job. This stuff, machining, has been around for a couple of centuries now, there are a lot of things that have changed but the basics.

    Tool materials have changed but to use the newest your machine has to be up to the same standards. A mini lathe isn't built with insert tooling in mind.
    Hobby machining doesn't have to involve the latest and greatest.

    About all you need for engineering and making gears, pulleys, screws and other machine parts is a Machinery's Handbook. And like tooling it doesn't have to be the latest edition, The basic principles and standards don't change.

    cary



  10. #10
    Registered thudson's Avatar
    Join Date
    Apr 2005
    Location
    USA
    Posts
    91
    Downloads
    0
    Uploads
    0

    Default

    I guess the tool holders are not that bad since they are mostly set and forget. I just don't have enough of them. And it just so happened that the 3/32 allen was the one size I couldn't seem to find.

    Cary, I know what you're talking about. I was fortunate to receive training from a very old-school French company. They started us out with a vise, a surface plate, a hack saw, and a set of hand files. The only machine we used for the first six months was a drill press. We made parts that were flat, parallel and square to less than a 0.1 mm.

    I've honestly been searching in vain for a set of the files we used. They weren't flat, they had a bump about three quarters from the handle, where the taper changed, that allowed you to file high spots on a flat surface.



  11. #11
    Registered
    Join Date
    Jan 2010
    Location
    usa
    Posts
    485
    Downloads
    0
    Uploads
    0

    Default

    Sounds like my machine shop instructor in High School. Had to make a set of jaws for a "parallel clamp" that way as a first project. Most places today don't teach a real trade, mostly "machine operators".

    Best (most interesting) job I had was a "job shop" never knew what would come through the door. Did everything from experimental Nuclear reactor parts (for Babcock-Wilcox) to refacing car flywheels.

    cary



  12. #12
    Registered knudsen's Avatar
    Join Date
    Feb 2010
    Location
    USA
    Posts
    709
    Downloads
    0
    Uploads
    0

    Default

    I guess the tool holders are not that bad since they are mostly set and forget. I just don't have enough of them. And it just so happened that the 3/32 allen was the one size I couldn't seem to find.
    I violate my own rule and put two different fastener types in:

    You can really torque down on those socket cap heads without them rounding out. the smaller setscrews in the middle are usually not needed, unless using a very short tool. Also the thumbscrew, sized to fit a human thumb, as opposed to whatever creature could grip the crappy original, is a nice upgrade:



    Thumb screws are the same diameter, so there is no trade-off, just easier to use.



Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


About CNCzone.com

    We are the largest and most active discussion forum from DIY CNC Machines to the Cad/Cam software to run them. The site is 100% free to join and use, so join today!

Follow us on

Facebook Dribbble RSS Feed