Centerless Grind Or Turn Down Od

Discussion in 'Turning Work' started by KBLZ, Jun 13, 2018.

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  1. KBLZ

    KBLZ
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    I have 52 different rods of prototype polymer that has been cast into 14mm OD (+/- 1mm) solid rods, ranging from 200-250mm long. I need these ground to 12.7mm OD (+ 0.00mm, -0.10mm), then sliced into "buttons". These buttons are 4.35mm thick (+/- 0.5mm), which should look like mini hockey pucks. All surfaces should have an finish of 3.2 micrometer RA.

    Traditionally, these are centerless ground to diameter, parted on a lathe into buttons, and blanchard ground to thickness. They can be made entirely using a lathe, and filing off the nub with a flat file. The flat faces can be slightly out-of-square, but should be minimal based on processing methods.

    These rods are for material research, and are similar to acrylic. Each rod is a different polymer and needs to be handled on a one-by-one basis to prevent mix-ups, as this would invalidate the data. The labeled portion of each rod can be cut off and remain unprocessed in the bag. Each rod will be individually bagged and labeled, and will need to be cut into buttons and returned in the same bag.

    Please advise the turnaround time and lot price via PM. General questions may be asked via a reply on the forum.

    ***The owner of this request does not authorize this post to be distributed outside of RFQWORK.com. All solicitations must come through RFQWORK.com. Any solicitations outside of RFQWORK.com will not be considered for this RFQ and any future RFQs***
     

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  2. brads precision

    brads precision
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    I would like to give you a quote on your parts. If you could email me at bradsguns@hotmail.com
     
  3. Alex thomas

    Alex thomas
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  4. Where are you at in Virginia? Do you have a durometer range (hardness) on the rods? Have you allowed for some waste on each rod? I think they would drive a grind shop crazy, anyone with a grind shop think differently? I would say stick them in the freezer then turn between centers. This is going to be a tough job to price accurately.
     
  5. Alex thomas

    Alex thomas
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    Shouldnt be too bad. Just turn about 5 discs worth. Then part them all off with a good sharp angled part blade. Then face next part if required.
     
  6. It depends on the condition of the cast material, "cast" means it can be anything.
     
  7. Alex thomas

    Alex thomas
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    Ah
    Ah Okay no worriew. i was just going off the pictures provided. Thanks
     
  8. KBLZ

    KBLZ
    New Member
    Hi Dualkit. We are in northern Virginia. The hardness ranges from 78-83 Shore D. When lathing these, I usually turn down the OD with the rod between 3-jaw and a live center, change over to a 1/2" collet, and trim the remaining gripped "shoulder". Then I use a parting tool to cut the parts into buttons. The cut depth is usually 0.02" @ 30IPM for roughing, and three 0.005" deep 15IPM finish cuts. Spindle speed is usually 1200 RPM until the rod is rotationally balanced, then increased to 3600 RPM.

    All rods can be cut at room temperature as they are similar to acrylic, except these don't melt. "Cast" rods in this case means that liquid monomers were mixed, poured in a closed-end tube, and cured into a solid. Lathe swarf is usually stringy in appearance, but it is more of a powder.

    Let me know if there are any more questions!
     
  9. Just buy a 14mm collet and go from there, it would save time.



     
  10. KBLZ

    KBLZ
    New Member
    Thread Closed. Thanks for your quotes!
     
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