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  1. #1
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    Default Drill press run out

    I have one of the cheaper but adequate Hare and Forbes bench drill presses ( D590 - BD-325 Bench Drill - Belt Drive | Hare & Forbes Machineryhouse ) and when I measure the run out slightly above the chuck on the morse taper I get an acceptable 0.03mm (about 1 thou). As I move down the chuck it gets worse. Measuring on a drill bit in the chuck I get 0.18mm (7 thou). My drilled holes are consequently larger than the drill bit and often it doesn't matter but sometimes it does. That told me that the chuck is the problem so I bought a keyless chuck from Carbitec that came with its own morse taper and got pretty much the same run out readings. Timbecon, Carbitec and Hare and Forbes all sell replacement chucks Are they all the same? I'm not after perfect precision but I like it to be slightly better than 0.18mm at the
    drill bit.
    Any personal experiences from people who have bought and are happy with a chuck from Timbecon etc

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  3. #2
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    Default

    I've got a bunch of chucks and FWIW here are some of their runouts in mm, performed in the same manner as you have tested

    DP MT spindle <0.005
    Original Keyed chuck that came with the DP 0.65

    The rest are all keyless chucks from McJing
    MT3:1 0.03
    MT3:2 0.56

    These are MT2 chucks that I use on my lathes. I tested their runouts on the DP by using an MT3/2 adapter which had a runout of <0.01.
    MT2:1 0.45
    MT2:2 0.56

    Except for MT3:1 all the other chucks have had a hard life including repeated use of multigrips to remove stuck bits. I now uses Boa Constrictor Belt Wrench similar to those used to hold pipes or remove engine oil filters.

    With the keyed chucks I've found the runout can depend on which hole is use to tighten the chuck, or if just one hole is used versus if all holes are used AND what order they are tightened. This really shows up on lathe chucks.

    TIP; for when holes are too big. get yourself a set of 0.1 mm bits - I have a set from 1 to 10 mm and they have saved my bacon many times - even with zero DP runout and a brand new drill bit, for a whole bunch of reasons there is very little chance a X.y mm bit will drill an X.y mm hole. The way the metal workers do is is to use an X.(y-2) mm bit and then ream the hole to the size, or on a lathe use a boring bar. With this method you can get holes to within 0.01mm.

  4. #3
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    Default

    Wow! My MT2 chucks at 0.18mm doesn't look that bad now compared to 0.56mm The 0.1mm bits suggestion sounds like a good idea. Thanks for that.
    The drilled holes aren't all that much bigger than the drill bit eg 40mm forstner measure at exactly 40mm delivers a 40.15 to 40.20 hole thereabouts and a 1" forstner bit can sometimes deliver 1.02" or close to it and all these are OK except when working with tight tolerances which isn't often.

    I guess the bottom line is .... should I buy another (better) chuck?

    Don't care about keyed or keyless but sometimes its a lot harder (needing to use other tools) to undo a keyless chuck particularly with larger cutters.

  5. #4
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    Yeah those chucks never recovered after using multi grips to undo bit and the occasional belt with a hammer.

    Buying a new budget level one will be a bit of a lottery with respect to runout.

    New quality chucks like a basic plain bearing Branded Jacobs only have an assured runout of 0.1mm and even their ball bearing chuck are only rated to 0.07mm
    Their High precision keyless chucks are rated at around 0.04mm but be prepared to pay MANY MANY hundreds of $$.

    If you want better than 0.1 mm, forget about 3 jawed chuck, A budget level collet chuck and set of collets will outperform even most 3 jaw Jacobs style chucks. To use these safely you need a metal mill with a threaded draw bar.

    Screen Shot 2019-08-15 at 1.26.59 pm.jpg

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  6. #5
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    OK I'll try Timbecon's keyless and report back. https://www.timbecon.com.au/drilling...ss-drill-chuck
    I guess my bank balance won't be hurt that much. if the run out is 0.1mm or better I'll be happy, if not I'll give up and use 0.1mm drill bits but as I said above its not often I need that accuracy

  7. #6
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    Default

    Often the oversize issue, and drill tips starting out of place is a very sloppy fit between the quill and the head casting, generally caused by a bell mouth created when the head is being bored. Testing for this is fairly simple, grasp the chuck body and feed the quill down about 1/4 of it's travel, and try to move the chuck body side to side and front to back. Any movement available indicates that the quill has corresponding slack in the head casting. Repeat at half and three quarter extension as well.

    The grasp and shake test won't reveal anything with the quill fully extended or retracted against stops because the stop will cock the quill assembly in the casting and effectively jam it into a fixed position, but there is no guarantee that the positions at each extreme will be vertically aligned.

    If a bit can 'walk' across a surface when starting the hole, it can start away from the centre axis of the quill and will then continue to drill the hole in an inclined fashion. This in turn tends to put uneven pressure on the cutting faces of the drill but, and can tend to make for an oversize hole. Of course, an incorrectly sharpened drill bit can do a similar thing as well, for the same reason, uneven forces on the cutting edges.

    I used the grasp and shake test over a couple of years when looking for a drill press years ago, and found that most of the Chinese and some Taiwanese drills under about $1000 retail had the issue. I haven't looked seriously for the past five years as I haven't needed another DP, but I would be surprised if the situation has improved. If you are drilling individual centre punched holes, the bit should pick up the punch mark and carry on from there, but for repetitive drilling using jigs etc to locate locate material and hence holes, it is not uncommon for a poor drill press to have location errors in the order of a couple of mm. This is one reason why many of the older light industrial drill presses hold their value in the face of cheap asian competition, they were accurately machined to retain accuracy over their lifetime.
    I used to be an engineer, I'm not an engineer any more, but on the really good days I can remember when I was.

  8. #7
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    [QUOTE=malb;2152785
    I used the grasp and shake test over a couple of years when looking for a drill press years ago, and found that most of the Chinese and some Taiwanese drills under about $1000 retail had the issue. I haven't looked seriously for the past five years as I haven't needed another DP, but I would be surprised if the situation has improved. If you are drilling individual centre punched holes, the bit should pick up the punch mark and carry on from there, but for repetitive drilling using jigs etc to locate locate material and hence holes, it is not uncommon for a poor drill press to have location errors in the order of a couple of mm. This is one reason why many of the older light industrial drill presses hold their value in the face of cheap asian competition, they were accurately machined to retain accuracy over their lifetime.[/QUOTE]

    This is the main problem with my DP. Its not so bad with the quill unextended so for improved accuracy I try to get the workpiece has close as possible to the bit. Starting some holes with a Centre Drill reduces drill bit itself wandering as well.

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