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Thread: Low-cost Indexing?

  1. #11
    tired of idiots vz58's Avatar
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    sorry I have been scarce lately. Time has been short.
    The collet that is supposed to be used in mine is unique. We went through the machinists bins and all the odd ball collets were not right. So we made a tool that I can dog to. BUT then I tried the r8 and although not what is supposed to be there it does and admirable job.

    Later

  2. #12
    Gunco Veteran Viper Dude's Avatar
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    Hello hc,
    As you notice there are lots of different types of collets and some have been obsolete for a long time.

    Most lathes use the "MT" or Morris Taper series as do many drillpresses. The MT can have an internal thread, a tang, or nothing else to retain them other than friction. They have been used on some small milling machines too but are mainly for drills and lathes that see little to no side forces that would dislodge those collets/work.

    Many of today's milling machines use the popular Bridgeport R-8 collet series. They too use an internal thread for a drawbar retention. The R-8's look like a small trumpet. They are intended mainly to hold tooling rather than work. They will hold up to about 3/4 inch diameter round bits etc.

    The popular work-holding collets are the C-series such as the C-5's. They are trumpet shape too but fatter than the R-8's and they have external threads that are retained by a tubular drawbar. That system allows work (usually rods, gun barrels ...) to reach through the collet and out the back.

    As far as I know the modest spindex type indexers are not worm-drive but simple direct turned devices that are stopped by a peg and lock-clamp at a desired radial position. They usually use the C-5 collets for small (1 1/8 inch diameter max) rod stock. You could likely make a small faceplate to go on a spindex type indexer maybe even a small 4-jaw chuck to hold odd shape work. However I don't think you can rotate that work and mill at the same time as can be done with a dividing head (those really expensive things).

    Hope this sheds some light on this collet stuff.

    VD

  3. #13
    Happy Camper hcpookie's Avatar
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    When I mentioned worm drive I was responding to a previous comment (yours?) that you could use these things to help cut auger-style worm drive screws. Sorry if that was confusing. About rotating the work, couldn't you use a stop on the Z-axis of the mill to determine a set height, then continually make small cuts at every one-degree increment? It would be SLOW but I think you could do it?

    What I'm really trying to figure out is how to cut those ~ 45 degree angles along the outside circumference, such as the locking lugs on the AK bolt. It strikes me that the way this is done is to orient the indexer at 45 degrees to the table's axis, then lock the work in 1 degree increments (?) to cut that angle with the mill. That's the only way I can think of to make those kinds of cuts. Yes I'm thinking about a US-built bolt! It is more of a "how can I do that" question than anything at this point.

    That is also how, I think, the "auger" style worm-drive of a helix-wound magazine would be cut. Like in the Calico-style or the Russian 9mm Bizon-style magazines. A metal rod chucked in the indexer, set to 30? degrees, and use the table to pull the work as you continually rotate the work in the indexer. I think? I'll try to find some plastic or something else soft to play with while I figure this out.
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  4. #14
    Gunco Veteran Viper Dude's Avatar
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    Hello hc,
    The fancy industrial grade indexing heads will many times have a PTO connection so they can be simultaneously powered in phase with the power-fed mill table. That allows cutting of spirals such as helical gears and cams or Calico-style mags. A spiral cam I believe is used in the HK belt feed rotor to turn the sprocket-cog system. The much simpler spindex types won't do this.

    Very narrow bevel gears can be cut using a simpler indexer with the rotational axis angled as you mention. A verticle mill can do modest gear cutting though production gears were cut on horizontal mills with angle tables.

    Yes, the spindex type indexer can be used doing small incremental cuts to achieve a partial radius. The mill Z-axis is locked as you mention. It is a bit time consuming.

    AK locking lugs (actually the cam lug)... let me get one out to look here...

    A Hungarian AMD-65 bolt is nicely radiussed and appears to be NC or tracer milled on a dividing head. The cam cut follows the radius of the bolt head. The finish is so fine as to conceal any tooling marks (precision grinding ??)

    A Romi bolt is a bit rougher and seems to be ground on simpler machinery. The cam lug appears to be angle ground with little or no rotation about its' firing pin axis. There is a somewhat flat area where the cam angle is ground. Interesting !!

    Those radiussed areas of the AK bolts are not vital to operation. They are rather cosmetic IMHO.

    Firearms bolts are usually hardened then have a ground precision finish.

    One last item... A spiral cam rod can also be made by twisting square (key) stock in a powerful lathe at extremely low RPM. The 4-jaw chuck holds one end of the stock and a vise at the tail end locks down the other end on center of course. The turning is done at perhaps 2 or 3 rpms.

    VD
    Last edited by Viper Dude; 04-26-2009 at 08:30 PM. Reason: bevel gear should read helical gear

  5. #15
    Gunco Maniac sjohnson's Avatar
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    It was done for aesthetic purposes on a door knocker, but I heated square key stock in a forge furnace until it was uniformly bright red, then twisted one full turn in it using a smooth-jawed vise to hold one end stationary and a crescent wrench to "spin" it. I don't know if I was lucky but the spiral was very uniform and no need for a powerful lathe.
    I have a daughter. I tell her, "911 is what you dial after you're raped. 1911 is what you should have before they try."

  6. #16
    tired of idiots vz58's Avatar
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    thanks guys, I gave up on my worn out keyless lathe chuck and ordered one with backing plate for 69.99

  7. #17
    Happy Camper hcpookie's Avatar
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    I got my indexer and 1" collet yesterday. Overall the quality looks acceptable for a Chinese-built device. About on par with the rest of my stuff.

    Now the *FUN* is going to be how to figure the increments for the indexing wheel! Does anyone know of a quick-reference chart? I was surprised that at the "zero" mark, the pin uses the #9 retainer slot. I had expected it to be at the "top" slot.

    I was also surprised that the base is solid, and has no provision for the T-slot retainers! That was a surprise. I have the clamping kit so I'm OK, but I thought I read these used T-slot retainers. I guess for a $40 indexing head I shouldn't complain!

    I am still looking for a good, inexpensive rotary table WITH indexing. The 4" model on Grizzly.com seems to be the best deal at $150, plus a chuck puts it just over the $200 mark. All the NICE ones on Ebay are WAY too expensive for my needs, since I have no plans to make muzzle brakes or other indexed gizmos to compensate for the price of tooling.
    Gunco Member #10

    http://pookieweb.net


    The "original" Boltcutter Rivet Squeezers:
    http://pookieweb.net/AK/rivet/boltcutters/boltcutter.htm


    Project Pink - the Pink and Blue AK-74:
    http://pookieweb.net/pink/pink.htm

  8. #18
    Happy Camper hcpookie's Avatar
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    Here's a nice indexing head with a chuck - $85 shipping from Poland. That's worth it since it has a chuck with it. Half tempted to buy it myself!

    Bison Dividing Head model 3575-6 ” – M 6.25" SMOOTH

    Bison Dividing Head model 3575-6 ? ? M 6.25" SMOOTH - eBay (item 310141996563 end time May-20-09 08:48:26 PDT)
    Gunco Member #10

    http://pookieweb.net


    The "original" Boltcutter Rivet Squeezers:
    http://pookieweb.net/AK/rivet/boltcutters/boltcutter.htm


    Project Pink - the Pink and Blue AK-74:
    http://pookieweb.net/pink/pink.htm

  9. #19
    gunco irregular moleman's Avatar
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    I have a bison 3-jaw chuck on my 9x20 lathe. It seems to be much better quality than the chinese 4-jaw chuck I have.

  10. #20
    Gunco Veteran Viper Dude's Avatar
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    Polish tooling is decent stuff as is Czech and Yugo tooling.

    VD

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