Free 186 More Best Homemade Tools eBook:  
Get 2,000+ tool plans, full site access, and more.

User Tag List

Page 2 of 3 FirstFirst 1 2 3 LastLast
Results 11 to 20 of 23

Thread: Another shear tool

  1. #11
    Supporting Member metric_taper's Avatar
    Join Date
    Mar 2017
    Location
    Marion, Iowa
    Posts
    585
    Thanks
    227
    Thanked 257 Times in 153 Posts

    metric_taper's Tools
    Reading through Tony's original post is loaded with information:
    Shear tools for lathe work.

    186 More Best Homemade Tools eBook

  2. #12
    Content Editor
    Supporting Member
    DIYer's Avatar
    Join Date
    Aug 2013
    Posts
    3,056
    Thanks
    772
    Thanked 1,850 Times in 1,652 Posts


    Thanks olderdan! We've added your Shear Tool to our Machining category,
    as well as to your builder page: olderdan's Homemade Tools. Your receipt:




    2000 Tool Plans

  3. #13
    Supporting Member Okapi's Avatar
    Join Date
    Mar 2013
    Location
    Switzerland
    Posts
    222
    Thanks
    346
    Thanked 132 Times in 76 Posts

    Okapi's Tools
    Thanks for posting that tool, it's the same technology with the use of an particular angle on a radius tool than we use on the shaper for superfinishing ?

  4. The Following 2 Users Say Thank You to Okapi For This Useful Post:

    NortonDommi (Feb 4, 2021), olderdan (Feb 1, 2021)

  5. #14
    Supporting Member DIYSwede's Avatar
    Join Date
    May 2019
    Location
    Stockholm, Sweden...
    Posts
    634
    Thanks
    415
    Thanked 799 Times in 319 Posts

    DIYSwede's Tools
    That's right, Okapi - AFAIK the geometry was originally discovered for shaper finishing tools,
    and for lathe work there seems to be consensus regarding <3 thou DOC, slow speed (<500 spm) and ultra-fine feed.
    Tedious to watch while turning, but then there's always some coffee to drink too...

    Some machinists report not having good results with carbide inserts, as they don't have very sharp cutting edges
    (their rounded-off edges are a design trade-off for keeping up those crazy high speeds & feeds and big DOCs).

    As I want to experience this further by comparing carbide tip and HSS shear tools for small work finishing-
    I just winged this together from a discarded 5,5 mm masonry bit:

    Another shear tool-carbide-hss-shear-tool1.jpg Another shear tool-carbide-hss-shear-tool2.jpg Another shear tool-carbide-hss-shear-tool3.jpg

    Clamp from a 12 mm square hot rolled, drilled and turned in the 4-jaw, slot cut with a hacksaw, a 15 min job.

    Small, easily tweaked for different shear angles and turned over for either HSS or carbide -
    just have to hone their edges before trying.
    Though carbide needs some careful low speed fine diamond grit to hone properly, HSS sharpens more easily, but gets dull faster...
    Compromises, compromises - the fun never ends!

    Cheers

    Johan
    Last edited by DIYSwede; Feb 1, 2021 at 03:19 AM.

  6. The Following 3 Users Say Thank You to DIYSwede For This Useful Post:

    NortonDommi (Feb 4, 2021), Okapi (Feb 2, 2021), olderdan (Feb 1, 2021)

  7. #15
    Supporting Member DIYSwede's Avatar
    Join Date
    May 2019
    Location
    Stockholm, Sweden...
    Posts
    634
    Thanks
    415
    Thanked 799 Times in 319 Posts

    DIYSwede's Tools
    -Well, what do you know?
    Lacking impulse control, I suffered an irresistible urge to take the tool (or the stock, rather) for a spin at work.
    So, with the tool only ground on a greenstone grinder - NO lapping whatsoever - I just gave it a whirl.

    Chucked a 15 mm coarse-turned piece of hot rolled, spun it at 450 rpm,
    0.04 mm/turn at the lowest available feed, and a 2 thou cut lubed with 50-50 waste oil and kerosene:

    Another shear tool-start-carbide-cut.jpg

    Turning the Carbide from right to left with a 10-ish deg shear angle acquired a "nearly ground" finish on this POS.
    Did a repeat cut at a mere half a thou DOC with amazingly good result, given the worn-down lathe.
    Swarf is very fine, wisp-like, and stuck in the oil film at the very fine cut.

    Then, turned the tool end over end to see how the HSS would improve the finish further
    (as per my previous experiences & reports from other, REAL machinists):
    First a Carbide close-up:

    Another shear tool-carbide-finish.jpg

    Then the HSS over the already good, previously cut Carbide finish:

    Another shear tool-hss-carbide-finish.jpg

    The result speaks for itself - in stark contrast to my and others' experience...
    The carbide (though even NOT honed) cuts nicer than the HSS does - EVEN with a smooth starting finish...

    Bliss! Yet another day of counter-intuitive results! I've experienced and LEARNED something even today!

    Maybe some here can find this piece of info interesting or useful!

    Cheers

    Johan

  8. The Following 4 Users Say Thank You to DIYSwede For This Useful Post:

    flyfr8rs (Feb 1, 2021), NortonDommi (Feb 4, 2021), Okapi (Feb 2, 2021), olderdan (Feb 1, 2021)

  9. #16
    Supporting Member DIYSwede's Avatar
    Join Date
    May 2019
    Location
    Stockholm, Sweden...
    Posts
    634
    Thanks
    415
    Thanked 799 Times in 319 Posts

    DIYSwede's Tools
    Oh, well...

    Home from work, no "next of kin" around, so I tested a few more materials in my "Walk-In Closet Shop"
    after honing the shear tool's edges with a 1000 grit diamond lap.

    First (left in pics below) a rough CCMT 10 thou cut at 900 rpm and medium feed;
    then 250 rpm w fine feed @ 2 thou DOC for Carbide (center) & "HSS" tip (right) @ 2 thou DOC.
    No cutting oil, and a shear angle of 13 degrees.


    Al 6082 (CCMT and Carbide hardly distinguishable, "HSS" inferior):

    Another shear tool-al-6082.jpg

    Hot rolled (Carbide excellent, "HSS" inferior to the CCMT):

    Another shear tool-hot-rolled.jpg

    Gas Spring Cylinder (Machined hotter than hot rolled (Carbide somewhat better than CCMT, "HSS" inferior):

    Another shear tool-gas-spring-cyl.jpg

    Mystery But Free Machining Stainless (Amazingly good and cool CCMT cut, equals Carbide, "HSS" sucks again):

    Another shear tool-mystery-stainless.jpg

    Conclusions: Masonry bit shank NOT from HSS - cutting edge got completely deteriorated on stainless and tool steel.
    Cheap CCMTs from BangGood were very fast and amazingly successful in giving a good finish on "the usual suspects".
    Carbide, when properly honed did darned well, but really takes its time to achieve it. YMMV.

    I'd better be careful with my assumptions in the future, when comparing these with a REAL HSS shear tool.

    Hope someone can find some useful info, inspiration or "Schadenfreude", patiently staying with me this far.

    Cheers

    Johan

    A few bonus pics:
    Another shear tool-carbide-hot-rolled.jpg Another shear tool-shear-swarf.jpg
    Last edited by DIYSwede; Feb 1, 2021 at 12:19 PM. Reason: Added info & pic

  10. The Following 3 Users Say Thank You to DIYSwede For This Useful Post:

    Home-PC (Aug 23, 2022), NortonDommi (Feb 4, 2021), Ralphxyz (Feb 1, 2021)

  11. #17
    Supporting Member Ralphxyz's Avatar
    Join Date
    Dec 2016
    Posts
    1,564
    Thanks
    2,378
    Thanked 279 Times in 228 Posts

    Ralphxyz's Tools
    I have gotten some really good results with Aluminium and HSS, I have some carbide tools coming to try them.
    Ralph

  12. #18
    Supporting Member tonyfoale's Avatar
    Join Date
    Nov 2016
    Location
    Spain
    Posts
    1,549
    Thanks
    679
    Thanked 2,628 Times in 705 Posts

    tonyfoale's Tools
    Johan,

    Not all carbide is equal. I am pleased that what was in a masonry worked so well but it might be worth trying others. The tips in those drills are compounded for toughness with sharpness and the ability to hold an edge of secondary concern. On the other hand the carbide for turning aluminium is compounded with a fine structure which can be sharpened to a keener edge and retain it longer.

    The shank of masonary bits is certainly not HSS. That would lead to a lot of broken bits. HSS is very brittle.

    Thanks for reporting your tests, very interesting.

    BTW. On aluminium I found no visually obvious difference between HSS and a sharp carbide insert. Same on mild and free machining steel but as you would expect the HSS did not like hardened steel but the carbide worked.

  13. The Following 2 Users Say Thank You to tonyfoale For This Useful Post:

    DIYSwede (Feb 1, 2021), NortonDommi (Feb 4, 2021)

  14. #19
    Supporting Member DIYSwede's Avatar
    Join Date
    May 2019
    Location
    Stockholm, Sweden...
    Posts
    634
    Thanks
    415
    Thanked 799 Times in 319 Posts

    DIYSwede's Tools
    Thanks again, Tony.

    The masonry bit was really just a quick find and "suck it and see" thing.

    Possible avenue of coming tryouts:
    Given the low rpm (over 100 sfpm I get chatter) and the slooow feed: 1 ipm,
    I wonder if perhaps having a steep angle (<15 degrees) would be advantageous?
    I've experienced better finish, less strain on the lathe, less noise and cooler turning
    when going in with a steep shear angle (contrary to most machinists on the Interweb that swear by 25-40-ish degrees).

    My thought, and a piece of vector algebra:
    Most of the (small, indeed) cutting force will then work "more horizontally" in the bed's longitudinal axis,
    where the leadscrew pushes against it,
    instead of the force trying to deflect the tip mostly downwards (and less to the tailstock) as in ordinary turning.

    I also consider that having a steep angle would equal a smaller nose radius on a conventional tool.

    At least my mini lathe lacks some rigidity in the cross- and compound slides,
    so deflecting that load off them seems to improve finish,
    and also makes even tiny-teeny DOCs possible (if one only could get that carbide crazy sharp).

    Any reflections on this are most welcome!

    ATB
    Johan

  15. The Following User Says Thank You to DIYSwede For This Useful Post:

    Okapi (Feb 2, 2021)

  16. #20
    Supporting Member Okapi's Avatar
    Join Date
    Mar 2013
    Location
    Switzerland
    Posts
    222
    Thanks
    346
    Thanked 132 Times in 76 Posts

    Okapi's Tools
    It takes a time to read and understand all when english is not your mothers'tongue, but all you wrote is similar as what I've experimented in workshop, using a lot of material with no provenance certified, I've made a lot of try with different cutting material too etc…
    And as you said it's not easy to give a permanent solution for finishing, using specific powder cutting steel from Ifanger as specific steel like which named Supercoup here used specifically for cutting with a good surface finish on the lathe, and different carbide tools, I can't have a permanent solution and at each time it need some proofing, just as you said Hss is generally not the better choice, just on small diameters where it is very difficult to have a tool making a minimal force on the turned part.
    The use of the tool sharpened like for the shaper with a radius cutting head with an inclination angle of 40-60° makes generally good results for me, but on parts with different diameters is difficult to use on all the length and you have to make a radius cut at the end.
    Thanks for making all this testing and pictures, it's need a lot of time and you take it for us!!!

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Bookmarks

Posting Permissions

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