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  1. #1
    SIM
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    Default Trunnion for Rotary...1st hand knoweldeg, opinions

    I have been tossed about buying or building a trunnion for our 4th axis for some time. I have a few jobs that I think would benefit if we didn't have to reposition several times.

    Often we make a dedicated fixture...which works perfect, but its dedicated.

    I think about going with a larger, supported fixture for a vise...but not sure if the unit will loose too much rigidity to be useful on most applications. Or if the idea is nice, but every operation becomes an ordeal trying to maneuver around Fixture or Vise.

    Then I think about the time spent fabricating a unit and maybe better to just buy an off the shelf...till I see pricetag and think I can make for a fraction of cost and build to suit my exact needs then I toss the thought back and forth...which is where I am now.

    So...I was hoping to hear what others may have used, made, could recommend, would recommend staying away from.

    This is the one I have seen and received literature on...Hardinge makes one that I know of and I've seen a few others around...

    Stallion Trunnions for use with Haas Rotary Tables - No need for angle and sine plates anymore!


    Thanks for input.

  2. #2
    Ox's Avatar
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    I have a Hardinge 10"/16C indexer, and it is built like a brick shithouse.
    No experience with their trunnions tho.


    Your post brought back a memmory of someone here poste\ing a cpl yrs back about a multi-4th unit that he built himself. It looked good. I think he had a viedo too.

    Kant recall who it was.
    May be able to find if you search long enough?


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  3. #3
    dstryr is offline Titanium
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    Subscribing to this post.... I've been going back and forth on the same issue and looking at the same product. Post up what you find out.

  4. #4
    PaulT is offline Stainless
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    I've also had thoughts of fabbing one up, along the design in the link you showed.

    It seems pretty straightforward to me, a pillow block type bearing mount on the far end and I'd just weld up hefty ears to a hefty piece of flat stock as the center tray.

    The plan would then be to level the ends carefully with shims on bearing holder on the far end and then just face mill the center tray flat right on the machine as mounted and at zero degrees, making it very true and square with the machine table, probably even better than a commercial one.

    Paul T.
    Power Technology

  5. #5
    Ox's Avatar
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    OK, my bad...

    I thought that you meant building the actual 4th and 5th axis'.

    Never heard the term "trunnion" used when not including a 5th axis...

    I have made several dedicated fixtures/tombestones for various parts over the yrs like you are talking about, but not for a vise.

    Yes - I have used 2" pillow blocks on the tailstock end.


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    dstryr is offline Titanium
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    Quote Originally Posted by Ox View Post
    OK, my bad...

    I thought that you meant building the actual 4th and 5th axis'.

    Never heard the term "trunnion" used when not including a 5th axis...

    I have made several dedicated fixtures/tombestones for various parts over the yrs like you are talking about, but not for a vise.

    Yes - I have used 2" pillow blocks on the tailstock end.


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    Lets see some PICS!!

  7. #7
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    Quote Originally Posted by Ox View Post

    Yes - I have used 2" pillow blocks on the tailstock end.
    How tight are those things? Is there internal clearance, and does it affect rigidity? Can you get them preloaded?

  8. #8
    Ox's Avatar
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    I don't think that I have any pics of any of the old set-ups, and I am not posting pics of current ones. If you come here, I can show you personally, but then I'd hafta kill yuh... you understand eh?


    How tight are pillow blocks?

    A) They are tight enough when twisted in position to hold the race from turning when used in a shaft application eh?

    B) I am only indexing for and aft. Never had an issue.


    I have 2 jobs running now that use a tailstock, and they seem good enough, but an act of Congress to adjust if you're after dialing them ratt in.

    The pillow blocks are the polar opposite as they will not be dang near perfect when you first put the setup together, but you can tweak it a WHOLE lot easier! Shim, Grind off the riser block, tap to the side a smidge.... That little tailstock just doesn't want to go for that stuff! LOL!


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  9. #9
    SIM
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    Quote Originally Posted by Ox View Post
    I have a Hardinge 10"/16C indexer, and it is built like a brick shithouse.
    No experience with their trunnions tho.


    Your post brought back a memmory of someone here poste\ing a cpl yrs back about a multi-4th unit that he built himself. It looked good. I think he had a viedo too.

    Kant recall who it was.
    May be able to find if you search long enough?


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    I remember, wasn't that Frank Mari.



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    Seems EZ enough to make...

    ...but to tweak unit to work exactly as needed is the time I am not sure I want to invest...sometimes just better off to buy one that has been perfected and make your money back on the production.

  10. #10
    Brian is offline Stainless
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    I used to build these intake manifolds for Arizona Speed and Marine....



    I built a trunnion type fixture like you linked to, used a Haas indexer on the Fadal mill. At the opposite end we built a right angle plate affair like your website, just went thru a 1.5" diameter hole I bored and honed into the plate, then on the outside end, I added a big aluminum home made pancake air cylinder. When the unit was done indexing, we used a spare M-code and locked the unit in place with the air cylinder. We never had any rigidity problems.... made a very complicated part pretty easy fixturing wise.

    All we did was deck the bottom of the parts, where it went over the lifter gallery and and had a few threaded holes we could use to bolt it to the flat part of the trunnion. Then we machined all the mating surfaces to the heads, the upper manifold, injector ports, distributor hole... all of it in one operation.

  11. #11
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    I have a couple of home made ones that work just dandy. My outboard support is nothing more than a upright with a bronze bushing in it. Believe it or not my outboard pivot is just a 1/2' dowel pin. Chatter is not a problem and I have been running the piss out of it for a year now. If I was doing some real heavy work I would go with a 3/4" pin.

    I do need to build another one that will accept a vise like the ones on Stallion Trunnions for use with Haas Rotary Tables - No need for angle and sine plates anymore!





    Oh.

    Here is one of mine.

    Nothing fancy. Certainly not in the same league as the Nikken table.
    Last edited by ARB; 02-16-2012 at 06:14 PM. Reason: Added pic

  12. #12
    PaulT is offline Stainless
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    I like it Arb, quick and simple to fab up but it looks like it works well.

    For small jobs it looks like you could fit one of the low buck 4" CNC vises right on that plate, you can get these on ebay for around $140., they're not for heavy usage but work ok for occasional use on smaller parts.

  13. #13
    Jon Bohlander's Avatar
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    I built a trunnion/tilt plate (not sure of the correct term???) for the 4th axis about 6 months ago. IIRC, I used a 6"W x 12"L x 1-1/2" AL that I found on the shelf. I pressed in steel pivot pins (also bolts/dowels through a flange). Skimmed top & bottom with it in the 4th and put in a grid of 1/4" reamed and 1/2 tapped holes. (that pattern fits some other shop-made fixturing) I'm supporting the outboard end with the tailstock. In hindsight, I would have made the pins hex, so I wouldn't have to indicate it flat each time I set it up.

    I've been very happy. Being able to combine operations or doing angles easily has made my life much easier. Not ridgid enough for hogging but good for general work. I am currently making another at home for my manual mill/dividing head.

    I've been meaning to ask, how ridgid are the half-bushing A-frame supports like Haas sells? They have more support but what stops any forces pulling up on the fixture?

  14. #14
    John_B is offline Cast Iron
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    I just got one of the Stallion trunnions late last year and finally finished the project I got it for this past Wednesday. It worked well, but I am kinda not impressed with the item. Granted the table is a cast piece which adds to rigidity, but it was supposedly machined to match the 4th axis faceplate I have (I was asked specifically which unit I had so they could match the pattern) yet it doesn't have all the mounting holes in the correct places. Additionally it is supposed to be made for a Kurt 6" vise, and have the keyway pre-cut - and it is there it just wasn't the correct size for Kurt vise keys.

    It's still on the machine, I'll try to get a picture Monday.

    Also, ARB I'm jealous of that Nikken on your Hardinge!


    Regards,
    John B

  15. #15
    kuraki556 is offline Cast Iron
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    I'm building a tailstock/trunnion for a Haas positioner, and from the replies here I'm going a little heavy on the tailstock. I was going to use 3" thick grade 50 and two 2" tapered roller bearings

  16. #16
    John_B is offline Cast Iron
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    Quote Originally Posted by kuraki556 View Post
    I'm building a tailstock/trunnion for a Haas positioner, and from the replies here I'm going a little heavy on the tailstock. I was going to use 3" thick grade 50 and two 2" tapered roller bearings
    Doesn't sound crazy to me, sounds nice and stout.

  17. #17
    Jon Bohlander's Avatar
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    Yeah, too rigid of a trunnion would be like too pretty of girl or too fresh of sushi, no such thing. With the one I made I had a budget of $0 and had to use what I could scrounge.

    I was skimming the one I am making at home last night and getting some chatter. I will have to make an A-frame some time.

  18. #18
    Ox's Avatar
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    Quote Originally Posted by Jon Bohlander View Post
    Yeah, too rigid of a trunnion would be like too pretty of girl or too fresh of sushi, no such thing.

    No experience with sushi, and would prefer to keep it that way, but I will dissagree with the too rigid comment.

    Available trq of your indexing unit is in competition with your fixture. I came to this comclusion after crashing a taping head and other toys a few times.

    Dateline 1993, I had a 3 (2-1/2) axis mill and wanted to doo 4th axis location for a fixtured part(s). I had ran a sister part in my other mill with a big rotary, with a short fixture mounted rigid (no outbours support) that held 5 parts I think. Now I needed to tool up for higher volume, and bout a used VMC with a toy changer, and then bought a new Haas 5c indexer. ... no ... wait .... I had that Haas unit already for some small parts - that's right....

    Anyway, I made a fixture that held 20 parts, and put a 2" pillow block on the other end. That little indexer didn't have hardly any trq, and occassionally it would git stuck due to a slight alignment issue once indicated sqr. And it would simply not finish the index. In my case, it was not a monitored action, and was only allowed a dwell time to complete the opperation. (no return M code installed)

    Eventually we ponied up for a rotary table and never had this issue aggin, but the lessen is still there, that the bigger and more rigid the fixture, the more bind that you could be puting on your indexing mechanism. Not saying that I would expect an issue, and I haven't had a rotary get stuck since - even on apps where the fixture is very large, just pointing out that the more rigid the setup - the more perfect needs to be the fixture.


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  19. #19
    John_B is offline Cast Iron
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    Quote Originally Posted by John_B View Post
    It's still on the machine, I'll try to get a picture Monday.
    Here's a picture of how the holes don't line up...


    100_7345.jpg

    The one in the center is too low to get into the slot.

    and a bad picture of the whole thing...

    100_7346.jpg

    Rgds,
    John

  20. #20
    Ox's Avatar
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    It looks to me like it was built for either 45* and 60* tables.


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