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Thread: Grinding head Collet types

  1. #1
    Join Date
    Jun 2005
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    Default Grinding head Collet types

    I recently acquired a Rockwell/Delta Toolmaker grinder. It was part of a bigger tool gloat that I may post more about later. Suffice it to say that I had on my someday list to own a small (my shop is way over crowded now) surface grinder as it and a few fixtures seemed like a more universal way to deal with sharpening cutters than a dedicated cutter grinder. This thing is not really a surface grinder per-say, but will probably perform that function adequately for my purposes. It has 6x12" travel.

    It came with most of the cool accessories including the Univise (for grinding single point lathe cutters etc) and the Unihead with indexing collars. This is a universally adjustable rotating grinding/indexing head...and I should be really grateful. However, it takes Brown and Sharpe #9 taper collets which I don't have and which are not very universal today. Fixing the grinder is a someday project, so I am in no hurry, but generally find that it is wise to start looking for the pieces you need for a project and do the in-head engineering in advance of being ready to start work.

    My thinking is that maybe the brightest idea would be to look for a collet holder for some other sort of small collet (perhaps one of the double-angle types) and turn the shank down to fit the B&S taper...making my investment in collets I don't currently own, a little more universal. Another collet holder like this could go in the lathe chuck etc. That has the downside of having tool shanks stick out further when grinding which would not be as rigid...and takes some work, but leaves things intact.

    Plan B is to disassemble the thing and figure out if I could make a replacement spindle that would handle 5c collets or something of the sort. This would mean an even more useful set of collets. That requires quite a bit of accuracy as a milling cutter with even minimal runout will tend to cut with one flute. The current "spindle" appears to be precision ground.

    Plan C is the obvious one....just save my pennies and buy a set of B&S 9 collets that will not get used for anything else.

    I am posting here for opinions as I am sure someone will set me straight

    Paul
    Paul Carpenter
    Mapleton, IL

  2. #2
    Join Date
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    Maine
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    Default

    I opt for Plan C. MSC www.mscdirect.com sells B&S collets. How many collets will you need? Not many. If I'm understanding the need correctly, you'll be using the collets to hold end mill shanks. Just two, 3/8" and 1/2", will likely take care of most of your needs. Add 3/16", 5/8", and 3/4", and you've probably taken care of virtually every end mill you'll ever have.

    You don't need "a set of B&S 9 collets."
    ----------
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  3. #3
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    May 2005
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    Default

    What about another plan. ISTR B&S 9 is somewhere near 4 or 5 MT.
    What about getting a 4MT or 5MT collet chuck, one which takes ER32 or ER40 collets. Then grind (or possibly turn) the MT shank to convert it to a B&S taper.
    You then have a modern chuck with readily available collets.

    I did the reverse with a drill chuck for my big lathe, took a 3/4" Jacobs chuck on a B&S shank & turned it down to 4MT. Worked a treat.

    Tim

  4. #4
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    Jan 2004
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    Taftville CT
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    Unhappy Wish mine had that stuff

    Quote Originally Posted by pcarpenter
    It came with most of the cool accessories including the Univise (for grinding single point lathe cutters etc) and the Unihead with indexing collars. This is a universally adjustable rotating grinding/indexing head...and I should be really grateful.
    I also have a Rockwell T/C Grinder, in boxes, minus the cool accessories. (Unless a photocopy of the owners manual/parts list counts as "cool accessories"). So I basically have a second surface grinder. Re-assembly is on my list of "to do" though not high priority. I won't hi-jack your thread with motor questions and whatever else I will need ask about when I eventually get around to it.

    I would think along the lines of SGW, buy the few collets you need/want as needed/wanted.

  5. #5
    Join Date
    Nov 2003
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    15

    Default

    I have a Unihead, and opted for making a 5C spindle for mine. Although there are a number of different options available such as making an adaptor from a #9 B&S to ER or double taper, etc. The 5C collet system is used in a number of lower cost import grinding and milling attachmnents, so I felt that
    I would base my tooling around the 5C collets. 5C collets can be found in round, square, hex, metric, etc.
    A few years after I had converted the Unihead to the 5C, I picked up a KO Lee 5C workhead which is very nice piece of tooling, but I prefer to use the Unihead.
    If you decide to convert to the 5C, and if I can be of any help, let me know.

  6. #6
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    Jun 2005
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    Default

    Thanks to all who replied.

    I think the plan may be to look for some used B&S collets to get me started with a secondary plan to make a spindle at some point. The MSC price for those collets means that 3 would cost me about what a set would from another place I found. I have a local surplus place that may be hiding a collet or two and I will look for that first.

    The conversion of an ER type collet chuck was what I was thinking of in my initial proposal. Frank Ford did something similar but used an old Erickson collet extension and just cut it short. Tapering the shank could answer my problem. The Unihead did come with an MT2 adaptor, so I might even find some variety of chuck that would fit that, but tolerances add and I hate using a sleeve if it can be avoided. This solution also means the tool hangs out further as well, but in a grinding operation, that may not be a big issue.

    Still, I think the best long-term answer would be to go 5C since they are so common state-side and allow for the largest tool holding ability. My goal is to invest in collets with the greatest universality. As a home shop guy, trying to have several sets of different style collets is probably not realistic. I have some maybe 1.75" end mills with 1" shanks, so 5c could be useful over time. The fact that Lou has done this answers the "is it doable" question. The only question remaining is whether making an accurate spindle is inside the envelope of my skillset I might consider roughing it and then taking it to someone who can grind it to final dimension.

    One could argue that a 5c spin index (import) is about $30...but the Unihead is...well...universal and far more adjustable for angle etc.

    The more I look at this grinder, the more it looks like a potentially very useful tool for a home shop. The round column on the grinder rang alarm bells, but unlike the downside to a round-column mill, it is a "keyed" column and we are only talking about grinding type forces....not a milling head with need for substantial depth changes. I just have a lot to learn about grinding.
    Paul Carpenter
    Mapleton, IL

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