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Cutoff or Parting Tool Blade Warning

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  • John Stevenson
    replied
    Years ago when I was on HSS parting blades I found that if you went round the cutter sharpening place you could scrounge for free or very cheap long wood planer blades off the 36" and 49" Wadkin planers that had reached the end of their life.
    So I grabbed a big handful and went back to work, Cut them up into 4" long pieces with an abrasive saw.

    Then got a square block of steel, probably 1 1/2" square and on three sides I milled some angles in it.
    One side has a 7 degree taper to do one side clearance which when split would give me 3 1/2 degrees either side. One side held the blade nearly upright so the top and bottom tapers could be ground on and the last side has a compound taper, 7 degrees on the side but tipped down by about 2 degrees to put the side clearance on the front.

    Probably took an afternoon to make the block but then get the block and 8 or so blades and in under an hour on a simple surface grinder with a stick chuck, I can have 8 brand new blades that fit my holder.

    Still got some but I'm mainly on carbide tooling now.
    Still have the block in a toolbox somewhere.
    I'll see if I can find it Sunday when I pop back into work and get a few pictures. At the time it was well worth the effort because of all the scrap planer blades I was able to get.

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  • boslab
    replied
    No great fan of the toolholder stick out on some of these parting tools, way too much I feel.
    I was never lucky with parting tools, I always ran too slow, huge chip load per Rev, dialled it up and much more repeatable reliable cuts, I'm using a Walter blade kindly sent to me by Blackforrest, it fairly zips through, no more cowardly hacksawing, slop in the cross slide wasn't a help either, I have a few sandvick tizzit as well now, very reliable tools, a QC toolpost is still on the list ( the old multi fix was removed, I would like it back but not likely!)
    I won't be buying any Chinese blades if I can help it, perhaps they are designed for wood, or candles
    Mark

    Leave a comment:


  • old mart
    replied
    My 3mm Kennametal and Kyocera blades will plunge 50mm. I bought a 6mm Kennametal blade and ten neutral inserts on eBay for a song, but haven't tried it yet. It looks like it would manage a greater depth, I must look up the specs.
    When I bought my tiny Chinese lathe from an old fellow who was obviously not experienced with machines, I chuckled when I realised that he had the hss parting blade upside down in the holder.
    Last edited by old mart; 03-24-2017, 05:25 PM.

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  • Bigtrev8xl
    replied
    I'm with ya there, parting off under power feed at 1000 rpm, no probs at all

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  • metalmagpie
    replied
    I buy T type cutoff blades from Victor. They have side relief and also have a groove on top that really helps reduce chip binding. They are import but they work great.

    metalmagpie

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  • thaiguzzi
    replied
    I use both HSS and tipped parting blades. I generally prefer my HSS blades (Eclipse), but sometimes a tipped blade is required. I also generally use HSS first for most general turning jobs. The thing is, ALL my HSS is brand name made in the UK/USA. Most HSS made in China or India is vastly inferior to the point of being crap.

    Leave a comment:


  • JoeLee
    replied
    I've noticed that my older T shaped cut off blades had a factory taper ground into them. I recently bought a few new (China) ones that do not.
    My solution was to lay the blade down on the grinder with a .005 piece of shim stock under the bottom edge and put the relief on both sides of the T.
    As mentioned........ carbide inserts are the way to go, but sometimes you may need to cut a groove at a specific width so the blades come in handy for that.

    JL............

    Leave a comment:


  • Carm
    replied
    Rich
    You could have a look at Belcar Products for carbide.

    Leave a comment:


  • wierdscience
    replied
    Originally posted by Rich Carlstedt View Post
    Thanks Weird !
    I was looking for something like your suggestion.

    The problem with the inserts is DOC.
    Sometimes I get pretty deep into the material and HSS cutoff blades allow deep penetration
    I also do many odd widths , so I have an assortment of HSS 3/8" tool-bits ground to sizes, like .040 and.050, but they are limited to .500 DOC

    I am confused -if you don't mind helping out
    The spec shows .75 max DOC, and the holder shows .125" min width, yet the inserts go down to .060 ??
    Is the thinner insert a shorter DOC ?
    Rich
    Rich,the thinner inserts will not work with those holders as the support blades are a fixed width.The widths you mention I am not sure can be had in a deep grooving insert holder.As you probably know once you get past 4x the width on a grooving tool you are in uncharted waters.The last time I did any deep grooving in the widths you mention I cheated and used the rotary table and jeweler's saw in the mill

    Even though these won't be of help for the narrower grooves,they are still worth having.They handle 90%+ of all parting chores and makes the task almost effortless.I find them on sale in MSC and on Ebay fairly often $50-60 will often times land a holder and a pack of inserts on Ebay.

    Leave a comment:


  • Rich Carlstedt
    replied
    Originally posted by wierdscience View Post
    Good luck,I bought some CTD ones $40 that were made in Mexico,poor grind and magnetic right out the box.Also bought some Latrobe,also imports,but from Bosnia,those were pretty good,but still cost a fortune for what they are.Your best bet are NOS on Ebay.

    Like several others though I went to inserted parting tools years ago. I am particularly fond of Widia Manchester CNC styple parting tools.-

    http://www.pdqtool.com/binder/a/at4a.html

    Both the top clamp and anvil are replaceable and a variety of parting inserts are available.
    Thanks Weird !
    I was looking for something like your suggestion.

    The problem with the inserts is DOC.
    Sometimes I get pretty deep into the material and HSS cutoff blades allow deep penetration
    I also do many odd widths , so I have an assortment of HSS 3/8" tool-bits ground to sizes, like .040 and.050, but they are limited to .500 DOC

    I am confused -if you don't mind helping out
    The spec shows .75 max DOC, and the holder shows .125" min width, yet the inserts go down to .060 ??
    Is the thinner insert a shorter DOC ?
    Rich

    Leave a comment:


  • alanganes
    replied
    :
    Originally posted by PixMan View Post
    Not really.

    Reason to own a carbide insert cutoff and never have to deal with such problems again.
    Originally posted by Doozer View Post
    Thumbs up!--D
    Can't I have both??

    PS - before I got done reading the OP, I KNEW PixMan would chime in on this. And I have to agree. He set me up with some good info on the whole parting off thing, and it made a world of difference for me. He's right...

    Leave a comment:


  • LKeithR
    replied
    Originally posted by PixMan View Post
    ...Reason to own a carbide insert cutoff and never have to deal with such problems again...
    Absolutely!!

    Leave a comment:


  • wierdscience
    replied
    Originally posted by Rich Carlstedt View Post

    The company that I use to purchase from in Michigan has folded up, so I am looking for decent blades.

    Rich


    Good luck,I bought some CTD ones $40 that were made in Mexico,poor grind and magnetic right out the box.Also bought some Latrobe,also imports,but from Bosnia,those were pretty good,but still cost a fortune for what they are.Your best bet are NOS on Ebay.

    Like several others though I went to inserted parting tools years ago. I am particularly fond of Widia Manchester CNC styple parting tools.-

    http://www.pdqtool.com/binder/a/at4a.html

    Both the top clamp and anvil are replaceable and a variety of parting inserts are available.

    Leave a comment:


  • PStechPaul
    replied
    Even my cheap HF mini-lathe parting blade has tapered side relief, as well as a bevel on the bottom to lock it into the toolholder. But too bad the blade slipped back into the holder and it broke, but the blade is still OK.



    Leave a comment:


  • Black_Moons
    replied
    Originally posted by Rustybolt View Post
    Any body else remember the good old days when that's how they came and you had to grind the relief yourself.
    Never owned one that came with relief ground in. Besides, you have to grind down the sides of the cutoff blade to have proper relief anyway, how far you do that determines how far you can stick the blade out, and how much you will have to cut off when it wears and you sharpen past the unreliefed section.. or it snaps.

    Leave a comment:

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