where to get a hollow point (female) carbide dead center? - Page 2
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  1. #21
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    Quote Originally Posted by ballen View Post
    Those solid carbide boring bars look like a perfect source of center holes. Thank you! I've ordered a 20mm diameter one with a 3mm through hole. If I put it at the workhead side, I can just clamp it in a 20mm collet. For the tailstock side I'll need to get creative, it's too big for an ER20 collet.
    Let us know what arrives in the post. It may be cheaper than a bottle of rather bad wine, but perhaps not even as useful (cooking?)

    Perhaps you both missed the obvious - or maybe I have?

    But when I see a bright, silvery section, then read: "all parts hardened and ground" - solid Carbide being ALREADY hard - it tells me the HOLDER is alloy steel, black-oxide or Parkerize finish, one end & the flat, but same-same alloy underneath, not solid-Carbide nor even Carbide-ended atall. Carbide would not be my first choice of materials in which to mount clamping screws, either.

    Soooo... I'm reading it as the boring-bar it is meant to hold as what is "solid carbide", and so-mentioned specifically largely because those can be harder by far to GRIP without risk of slipping than more readily deformable material.

    I've been wrong before, but at least there's no shortage of wine for cooking..


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    For making this tail you might lathe turn a piece to be the needed taper with having a center both ends to be like a drill taper shank with two inch stick out stub from the tail.

    Might be just CRS, or TS harden it to about 45-48c, (just soft enough to drill and bore).

    After taper and stub stick out is done as a centered part, Then put it into the lathe taper to drill and bore a light press fit to take the the boring bar to 1/4" stick out from the steel.

    Then with a large center in the lath head stock as a center to the bored hole and held between center of the lathe head and tail, tickle the steel OD and the taper. This way it should all run near dead true.

    (x) The corner bevel of the boring bar (or a drill bushing) likely to be 45% so not as good as having a 60* you might grind the with a diamond burr or a mandrel point mount diamond wheel, *so perhaps the cut off cutter would be best.

    With this done, and the carbide bore hole done you can make pull-plugs to fit that hole to be a number if different tail needs such as bell, female, odd shape centers as needed.

    *or just cut off and anneal a drill with having a taper shank and then drill and bore the needed bore.

    *Re: thermite might be right in post 21. If so you may still need find a carbide drill bushing or a cut off centered cutter for this project..and using the above method.

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  5. #23
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    Yes let us know what the business end of these are.
    I see tapped holes for set screws which is way, way expensive in carbide.
    Normally it's a carbide bar with a brazed on steel head.
    Done right you hardly see the seam but the head is hardened steel.

    Do you really need carbide? Prepared to regrind it in place every time it is mounted?
    Bob

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    Quote Originally Posted by thermite View Post
    Perhaps you both missed the obvious - or maybe I have?
    You are right, the holder is steel, intended for a solid carbide boring bar. The seller was nice and let me cancel the order.

    I went through my collection yesterday, and found that I have some 16 and 20mm solid carbide end-mills with very good center marks. Until another solution turns up, I can mount those backwards in a collet in the headstock.

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    Quote Originally Posted by CarbideBob View Post
    Do you really need carbide? Prepared to regrind it in place every time it is mounted?
    I'm not following you. I would like to get a carbide hollow-point dead center because I am finding that steel on carbide runs smoother and is less likely to give issues than steel on steel. Why would a carbide hollow-point center need to be "reground in place every time"?

    Note that I don't assume that centers are concentric. I tweak the swivel table to grind cylindric, use that as zero, then rotate the swivel table for tapers.

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    Quote Originally Posted by ballen View Post
    I'm not following you. I would like to get a carbide hollow-point dead center because I am finding that steel on carbide runs smoother and is less likely to give issues than steel on steel. Why would a carbide hollow-point center need to be "reground in place every time"?

    Note that I don't assume that centers are concentric. I tweak the swivel table to grind cylindric, use that as zero, then offset for tapers.
    THIS.. is why some of us have trouble following your justification of the need.

    "We" use ball-centers, trapped ball-bearings, and such - often on live centres with rather good bearings - for turning.

    Turning USUALLY has far higher loading than grinding. So yes, we appreciate carbide tips, but no, not because hardened steel isn't GOOD enough. The workpiece will ALWAYS degrade before even a cheap ten-dollar-each Chinese-made steel centre goes useless. At those prices, there are spares in the drawer, too. Riten and Stark centres I tend to save for measuring more than for turning.

    Carbide is just less fussy about lube, and tends to last longer. Helpful, certainly, essential not really.

    Not to put "too fine a point on it", but if you are working tapers by set-over? That is not the same as a swiveling or "universal" table where the whole secondary axis is re-oriented with respect to another or "primary" axis.

    For "set over" you don't WANT an attempted mating of right-circular cones arguing with each other - as the old limerick went: "as to whom had the right to do what, with which, and to whom".

    What you want for those cases are a mating of hemispheres that can find circles of agreement, rather than cones of argument.

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    Quote Originally Posted by thermite View Post
    THIS.. is why some of us have trouble following your justification of the need.
    In the past year I have had several instances of steel-on-steel (standard 60 degree, not ball) going wonky. Not sure why, but this has never happened with steel on carbide. So I prefer that.

    When I said "offset" I meant "rotating the swivel table". I have edited my previous post to clarify that.

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    Bargain kit (most bargain brands will have .0002 or more run out IMHO.)
    MT2 Live Center Set

    Another bargain brand:
    https://www.amazon.com/Hurricane-Tur...teway&sr=8-171


    Skoda set (used)
    Skoda MT5 lathe live center set model # 310-715 | eBay

    The use of a taper #2 shank drill and made the way I explained in post22 seems best for home made.
    Bored in a lathe head stock it would run very true. Yes then after made used in the #2 tail stock.

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    Quote Originally Posted by ballen View Post
    In the past year I have had several instances of steel-on-steel (standard 60 degree, not ball) going wonky. Not sure why, but this has never happened with steel on carbide. So I prefer that.
    I've used ever-thing from genuine "white lead" thru Never-Sieze Moly on centers. My current preference is pink slime AKA "Cimcool Center Saver"

    http://www.cimcool.com/wp-content/up...ER%20SAVER.pdf

    When I said "offset" I meant "rotating the swivel table". I have edited my previous post to clarify that.
    Noted, thanks. That makes more sense.

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    QT:[steel on carbide. So I prefer that.]

    I have not yet tried this but wonder if having the mating of a center might hit in smaller/not full contact, with having a hollow full of wheel bearing grease..so the fibers in that grease might draw continuing lubrication to the mating parts.

    Still if you can remember to wash you hands....
    Basic Lead Carbonate ('White Lead&apos 4 oz | eBay

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    Quote Originally Posted by michiganbuck View Post
    I have not yet tried this...
    Don't bother, now, then. Doesn't help.

    "Cimcool Center Saver" by contrast, is out of a name you may recall. Cincinnati Milacron.

    I'd wager they've forgotten more about controlling center wear than most other folk have had time to learn.

    Anyway, not only does it JFW for turning, they list grinding ops among the applications.

    Cheap enough stateside, (avoiding MSC, anyway). Don't need a 55 gal drum of it to try it yerself:

    Cimcool Lathe Center Saver 2 oz B00400 00400 CS400

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    How big is the work? For small stuff you could buy a sapphire ring jewel or V jewel and press it into a steel holder.

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    Quote Originally Posted by Conrad Hoffman View Post
    How big is the work? For small stuff you could buy a sapphire ring jewel or V jewel and press it into a steel holder.
    Stock items, synthetic corundel watch and clock pivot jewels. Fragile, too, sadly.

    But NOW we've gone and done it!

    Nothing for it, but our easily compulsivated brother ballen will switch off Carbide in favour of CBN... or maybe a femto black hole magicnetically restrained?

    Wonder what the wear-rate is, steel on celestial wormhole?



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    Quote Originally Posted by michiganbuck View Post
    Bargain kit ...
    These are all links to steel live centers. I am looking for a carbide hollow dead center.

    The use of a taper #2 shank drill and made the way I explained in post22 seems best for home made.
    Bored in a lathe head stock it would run very true. Yes then after made used in the #2 tail stock.
    I'll first try the hollow point at the end of some of my solid carbide tooling, held in a head stock collet.

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    I was thinking you might use a live female so it would run in your tail with having no friction, so a steel female might be OK.

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    Quote Originally Posted by michiganbuck View Post
    I was thinking you might use a live female so it would run in your tail with having no friction, so a steel female might be OK.
    Ok, I see.

    I use live centers on the lathe all the time but not on the grinder, because I get more precision with dead ones. The grinder came with a Gepy MT2 live center that has much less runout than any of my other live centers, but still not as good as the dead ones.

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    Agree one can't beat dead centers for close work.

    OT: for a lathe operation one can/might go through the steps in my post 22 to make a bore for a bearing (with having a knock-out hole at back) to make a very simple and low cost live female lathe tail center. Yes don't depend on the bearing but make a 60* hollow inset to go in the bearing.. and a male point as well... Shouldered points would deflect chips and coolant.

    https://www.amazon.com/dp/B01GYWA29Q...s%20Guaranteed.

    No, I have never made one..just thinking

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    Hi Buck,

    Quote Originally Posted by michiganbuck View Post
    Amazon
    Your Amazon link points to skateboard bearings. What did you mean to point to?

    I agreed that making an MT2 taper fitting with carbide bits inside is fairly easy. It's on my to-do list!

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    Just low priced bearings..If somebody wished to make a live taper end center for a very low price. Use a scrap taper shank drill + $3.00 bearing (or two back to back). anneal the drill then a couple hours work and have a live center.

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    When my accumulation of dead centers can no longer be reground, I had planned on ordering up a set of carbide preforms from MSC, then silver brazing to shank (that's how they're constructed). Those MSC blanks are inexpensive, and are OD ground. I found other suppliers, but never wrote them down-perhaps one of them might stock a female center.
    By the by, folks have mentioned morse tapers for the grinder: I thought most grinders used Jarno taper, at least, my old Norton universal does)


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