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Collets Blocks Redux (long post)

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  • Collets Blocks Redux (long post)

    Smokedaddy this is for you. If tou haven't researched anything on 5C collets go to the Hardinge Work Holding website and peruse the catalog The wide range of tooling, fixtures and workholding solutions for 5C collets has made them almost universal for a lot of applications. While they are not perfect they are extremely versitile. One of the uses is in the common 4 and 6 sided collet blocks. Another is in index and dividing heads. But for odd sided collet blocks you have to make your own. I have never seen them commercially available. One thing you need to know if making you own odd sided is the angle between the coresponding sides that you are indexing off of

    As theCAD drawing above suggests some odd sided blocks are sore readily made than others. The Ageless Engine people actually suggest that some one building one of their engines start with the 9 cylinder as it is easier to set up the parts for machining
    If one is attempting to make one of these collet blocks one will need some of the following items

    The two 45D angle blocks are the resting surface for the 1.250" diameter bar stock. Also shown are a machined 5 sided block and a blank. In the mill the set up for the first side is as shown

    After this side is milled (we want around 1" finished dimension to the centerline) it is indexed so that the machined surface is postitioned up against a 36D solid angle

    Machine this surface to the same dimension as the first and index so the surfac you just machined is againt the solid angle. This is the last surface.

    After the main surfaces are machined and everything is deburred place the block on one of the surfaces and take a cut to break the corner

    The following links are from when I was checking the overall difference between the five sides.
    If one is carefull the parts can be held much closer, but these will wind up gettin gropund anyway.
    And this is for Evan. The shots in the mill alot of them the cutter was running at 1500 RPM and the camera (an old Panasonic floppy/superdisc type stopped the motion pretty good. I was really suprised)

    [This message has been edited by Spin Doctor (edited 12-11-2004).]

    [This message has been edited by Spin Doctor (edited 12-11-2004).]
    Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.

  • #2
    Cool, thanks for taking the time to put this together. For a complete novice, like me, it looks like an interesting and useful project. I’ve never bored a thing in my life, although I think I have everything I need. A couple of questions for you …

    1. What material would you suggest using?

    2. Is the bore in the collet block a standard I.D. size for all collets?

    3. What's the significance of the cylindrical stock going through the center of the collet block in the vise?

    4. Are the (2) 45 degree resting blocks type parallels something you made or can you purchase them? Do they have a specific name? I think I’ve seen something like those on eBay.

    5. It isn’t crystal clear to me how you would actually measure the flats, width and depth, therefore making them all symmetrical?

    Hey, I’m stupid,


    • #3
      The blanks were made out of 4140 Shafting (35RC) material from a shaft that got relace in one of our filtration units at work. When they replace a shaft I'll cut up the old one for projects.
      The bore is 1.250 which is the body size for 5C collets. Other collet sizes have different dimensions. The Hardinge catalog should ahve all of the major collet types listed
      The round stock acts as a locator for the blocks so all of the cuts are made with the centerline of the bore at the same height
      The 45D solid angles are something that I made up along with a variety of other angles (30,25, 20, 15) There are comercial versions out there but I'm cheap.
      To measure from the flats one could use a dpth micrometer or the head end of a dial caliper. For this I just cranked the mill's knee up to the same number on the dial. Each side wa three cuts. Two of .100 and one of .050"
      I hope this is a little clearer now. Remember there are no stupid questions except those that don't get asked.
      Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.


      • #4
        Great article, thanks I plan on making some. this will be invaluable help.



        • #5
          Must be nice to get that "scrap" every so often - lucky bugger! Nothing like being a pack-rat and on your toes when opportunity knocks, eh?


          • #6
            <font face="Verdana, Arial" size="2">Originally posted by Thrud:
            Must be nice to get that "scrap" every so often - lucky bugger! Nothing like being a pack-rat and on your toes when opportunity knocks, eh? </font>
            Dave, at least I am concious of the need to use scarp material for government work (for those who don't understand the term it come the constitution "of the People, by the People and for the People" aka "Swiss Navy Jobs"). However we do have over a 120 people in the shop on three shift covering the whole facility. So I suppose some virgin stock gets used once in a while. I do try to keep my projects to noon but the work flow is always in kind of a sine wave. Up to your ass in aligators one week and the next is slow. That's how maintenence shops go. Our boss would rather see guys busy with a project of their own when things are a little slow as the big shots don't know the difference when they walk through.It must be true of management in all places, the Peter Principle always applies

            Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.


            • #7
              Great information on the kind of tooling that can save time in low volume work.

              I have used this style of collet blocks in the past including the type with a small lever type closer, but have always wondered why the only collets that are used are the 5c collets. I have always thought that since the most use from these devices is in a mill and since most mills have a rack of R8 collets next to them, wouldn't it be handy if they were available for the same collets that the tool you are using them in used?

              I have not seen any but for the 5C, has anyone seen one that would use a milling collet, or even anything other that the 5C?

              I do not have a set of 5c collets in my home shop, but do have several sets of R8 collets. I wonder if the availability of 1/64" increment collets off the shelf for the 5C's and the ability to use an emergency collet, turned in a lathe for any size up to an inch is the reason?

              I may just have to make a set for my mill collets, thanks for the information/inspiration


              • #8
                Actually, it's because 5Cs are hollow. You can clamp a workpiece longer than the collet itself. With an R8, you'd be limited to a piece only a few inches long.

                Also, the 5C has a greater OD capacity than the R8. I believe R8 only goes to 7/8", while a 5C can go to 1-1/4" or 1-5/16".

                Between those two, the 5C is simply a better choice. Doesn't mean you can't make some R8 collet blocks (it's an interesting idea) with a short drawbolt to clamp parts.

                Doc's Machine. (Probably not what you expect.)


                • #9
                  The largest size that will go through 5C collets ia of course 1" and sometimes not then unless you give the threads on the back end a light hone. I think the reason we don't see more HSMers using 5C's is the fact that their lathes have small through holes so they frelly can't take advavtage of them. I am actually thinking of making some that take 3J collets as we do have a couple of lathes at work that use them or possibly Jacobs Rubberflex due to their muh larger opaerating range. And that is the big drawback with 5C collets is their limited clamping range
                  Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.


                  • #10
                    I would kill to work in a shop like that - you lucky bugger! Kiss the boss for me!