Using a press drill for bushing - Reamer dimensions question

Discussion in 'Clock Repair' started by uzi_i, May 10, 2020.

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  1. uzi_i

    uzi_i Registered User

    Aug 25, 2013
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    Hello everybody!
    I plan to use my bench press drill for bushing. My compact press drill is equipped with a chuck that can hold maximum 6mm bit.
    Can someone please tell if this can hold Bergeon or KWM reamers?
    thx, uzi.

    reamer.jpg
     
  2. David S

    David S Registered User
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    KWM reamers have a 4 mm diameter shank.

    David
     
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  3. Willie X

    Willie X Registered User

    Feb 9, 2008
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    Probably, I can get you the exact measurement.

    Note, you will ALWAYS HAVE to center the worn hole by fileing or nibbleing. Only then will your drill press be able to finish the job with reasonable results.

    I would doubt that a 1/4" drill press would have the low speed that is necessary. The reamer doesn't take that much torque if fed slowly, as it should be. RPM needs to be around 120 or 150.

    Willie X
     
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  4. roughbarked

    roughbarked Registered User

    Dec 2, 2016
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    It is so easy to ruin everything with a drill press.
    Also, I ruined a good drill by "running it too slow", according to my electrical repairer. "wasn't designed to run this slow continuously". Even though the variable speed control would allow me to set it there.
     
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  5. R. Croswell

    R. Croswell Registered User

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    KWM and Bergeon reamers were intended to to be turned slowly by hand is a "machine" that holds them perpendicular to the plate. If you use them in a drill press under speed and power you will likely find that the reamed holes will be larger than the size of the reamer, depending on the condition and precision of your drill press, the speed, and how long the reamer is allowed to run at full depth.

    RC
     
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  6. MARK A. BUTTERWORTH

    MARK A. BUTTERWORTH Registered User
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    We have used our table top Craftsman drill press for 30 years with no problem. We have it set to the lowest belt speed. The pivot hole does need to be re-centered first by filing.
     
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  7. roughbarked

    roughbarked Registered User

    Dec 2, 2016
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    I suppose if you re-determine what may pass for what can be called a drill press. Accuracy is important.
     
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  8. disciple_dan

    disciple_dan Registered User
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    I've been doing it this way for a year or so with great results. Care must be utmost when doing it this way.
     
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  9. uzi_i

    uzi_i Registered User

    Aug 25, 2013
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    Hi everybody,
    thank you so much for the valuable information. I'm not a clock specialist...clocks and watches are my hobby.
    Even though, I do care very much about the details and do a thorough study on every item before I'm starting. In this case, I don't mind doing few experiments with my bench drill - after all the dedicated bushing tool is quite expensive for my hobby.
    I will try to follow the guidelines you've listed above. I will keep you posted.
    thank you again, uzi.
     
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  10. disciple_dan

    disciple_dan Registered User
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    Hello, uzi. What I do is, file my bearing hole to oblong and then broch it back to round and then finish it with the reamer in my drill press. That's a little time consuming but my hands get cramped up when I try to do it all by hand. My drill press is a Wen and has very little run out. I was surprised at the quality of the drill for the money. I hope that helps, Danny
     
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  11. shutterbug

    shutterbug Moderator
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    I think a drill press with a belt speed control might be better able to weather the constant slow speed setting.
     
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  12. uzi_i

    uzi_i Registered User

    Aug 25, 2013
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    Hi,
    I will probably use one of the following compact press drills which I believe will be good enough for this task:
    Proxxon tbh PROXXON - TBH
    Proxxon tbm 220 PROXXON - TBM 220

    but I'll be happy to examine other alternatives for compact press drills.
    (the reasons why I insist using press drill over the bushing tools are 1) press drill is much cheaper. 2) press drill will be used for other purposes)

    thx, uzi.
     
  13. shutterbug

    shutterbug Moderator
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    That second one sounds pretty tight. It would likely make a good bushing machine.
     
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  14. David S

    David S Registered User
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    To be really helpful the X-Y table would be a good addition. However if you add stuff up how close will you be getting to the Sherline mill?

    David
     
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  15. Simon Holt

    Simon Holt Registered User
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    I have the TBM 220, and while it has high rotational accuracy, I found some issues with using it for bushing work:

    1. The collet system only goes up to 3.2mm - too small for Bergeon reamers and centers
    2. Although you can use a Jacobs chuck instead of the collet system, the maximum speed is (I feel) a bit too low for milling. I tried it once and ended up with an odd-shaped and over-sized hole.
    3. The minimum speed is too high for reaming

    I have the Proxxon mill (PROXXON - MF 70), which I use for finding centre and then milling a hole at centre. I then use a big old drill press at its lowest speed (600 rpm) for reaming (no need for accuracy as the reamer will find centre) and then pressing in the bush.

    Simon (still on the learning curve so take it all with a pinch of NaCl)
     
  16. tom427cid

    tom427cid Registered User
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    So true.
    tom
     
  17. uzi_i

    uzi_i Registered User

    Aug 25, 2013
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    Hello Simon,
    thank for sharing your observations. Few notes / questions:
    1) English is not my native language so I find it difficult to understand the difference between milling and reaming.
    2) I also was looking at MF 70 but I'm wondering why don't you install Jacobs chuck on the MF 70 and then use it also for reaming?

    one more question to Mark
    Can you please elaborate what do you mean "re-centering by filing"? I do understand the necessity of centering is to ensure that after bushing, the pivot will "seat" on its original location. but what is "filing"?

    thank you again all for the time and patience

    thx, uzi.
     
  18. Simon Holt

    Simon Holt Registered User
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    Hi Uzi

    I'm not in any way an expert here - I trust others will join in to help you. Also, searching the message board for posts on this subject - especially those by Jerry Kieffer - will give you far better guidance than I can.

    But in the meantime, here is what I have found:
    Milling is used to create a hole directly centred where you positioned the tool. It will not deviate from that centre provided the mill is accurate and the plate is locked. But you have to find centre first, by using a tapered tool in the mill and lowering it while the plate is free to move, then lock down the plate. The tapered tool will have found the centre of the original hole.

    Reaming can be used to create a hole of the required size when the original hole is not perfectly round. So if you don't have a mill, you can file the mis-shapen pivot hole so that the wear on one side is replicated on the other side, then use the reamer to create the right size of hole to take the new bush. But the filing requires using judgement, while using a tapered centre finder in the mill doesn't.

    In my case, instead of filing, I usually mill a hole to (say) 2mm, then use a (say) 2.97mm reamer to accept the bush. A 3mm mill would create too large a hole, hence the need for a reamer.

    Reamers are meant to be used at a low speed, and the lowest speed of the MF70 is way too fast.

    Simon
     
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  19. roughbarked

    roughbarked Registered User

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    If the reamers provided by KWM, Bergeon and others are turned slowly enough, no pre-filing for centering is required. If one notes, they are parallel reamers or cutters to be more precise,.
    They are not twist drills.
     
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  20. MARK A. BUTTERWORTH

    MARK A. BUTTERWORTH Registered User
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    I use a file to cut away metal opposite to the direction of wear and cut an equal amount on the unworn side so the opening on both sides of center are equal. Then the bushing reamer (KWM or BERGEON) will self center in enlarging the hole to the proper size.
     
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  21. fbicknel

    fbicknel Registered User

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  22. uzi_i

    uzi_i Registered User

    Aug 25, 2013
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    Hi Simon,
    thank you very much, you made it very clear.

    Hello fbicknel,
    WOW this is very impressive!
    two questions please :)
    1) what brand/model is your press drill?
    2) why don't you attach the reamer directly to the chuck but using the handle adapter?
    thx, uzi
     
  23. fbicknel

    fbicknel Registered User

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    It's a Harbor Freight 10" drill press.
    For control. The motor spins everything too fast and it's just too little control over the process. I'm reaming, not drilling... there's a difference, I think.

    Also, there's an adapter (I use the KWM system, I'm guessing Bergeon has a similar adapter). This lets you chuck up the adapter, then quickly change tools as the job progresses.

    Here's the adapter:
    upload_2020-5-13_8-25-15.png

    Here's the adapter chucked up with the centering tool:
    20200513_082334.jpg
    With the III size reamer:
    20200513_082259.jpg
    With the anvil, aka: pushy thingie:
    20200513_082322.jpg

    Rinse, Repeat.
     
  24. fbicknel

    fbicknel Registered User

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    #24 fbicknel, May 13, 2020
    Last edited: May 13, 2020
    Also, what Mark said above regarding removing the same amount of material on the opposite side of the wear is critical. Reaming will take out a precise amount of material, but it will center that removal on an average of where the hole is you are reaming. If your hole has wear on one side, then the resulting hole will center on a place midway between the center of that wear and the center of where the hole was designed to be.

    By removing material on the opposite side of the wear, you put the new center for the reaming operation back where the design center for the pivot should be.

    There's a whole bunch of information here that will be of use to you. Especially pertinent to this conversation is this article (listed in the How-to-do-it articles from that first link), which lays out what I just said in great detail. Instead of broaching by hand, however, I'm reaming with the KWM reamers. It helps a lot with understanding why you're doing all this filing before reaming stuff.

    I admit I don't do all the scribing and layout work here. About the best I can do is look at where the pivot lands when it's in the "wear" position, then observe the direction opposite that. I'll usually mark that on the plate (the direction), then file a bit in that direction to compensate for the wear. The detail in the article does help you understand what's going on, though.
     
  25. David S

    David S Registered User
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    If your drill press is rigid enough you can eliminate the hand filing operation.

    I use my drill press with a 6" x 8" X-Y table as a mill and do all my bushing on it. I use the KWM system for bushings. Once the original centre is found, Lock the X&Y axis remove the centre finder and insert a Ø2.5 mm 3 flute centre cutting end mill and mill through the plate. I follow with the #3 KWM reamer by hand with tap follower and reamer holder that I made.

    plate mounting fixture.jpg centre finder and worn spot.jpg per drill with endmill.jpg reamer in tool with tap follower.jpg

    David
     
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  26. shutterbug

    shutterbug Moderator
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    Yes. If you have the plates very firmly positioned and are sure that they can't move, you don't need to file. But you do need to "nibble" the unworn side of the hole slowly so you don't force movement of the plate which would cause the new hole to lose center.
     
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  27. uzi_i

    uzi_i Registered User

    Aug 25, 2013
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    Hi,
    well, it took me a while to digest the excellent information you guys shared. thank you.
    Now that I understood the meaning of "file of worn hole" I have a question:
    In my case, the pivot hole (while measuring the pivot using micrometer) is 0.76mm. is there such a tiny filing tool to file the hole?
    thx, uzi.
     
  28. roughbarked

    roughbarked Registered User

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    Yes. There are tools to hand start what others would prefer to be hand finishing.
     
  29. Simon Holt

    Simon Holt Registered User
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    This is what I use for pivot holes that small:
    Round (3021) Vallorbe Swiss

    Simon
     
  30. uzi_i

    uzi_i Registered User

    Aug 25, 2013
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    Thank again Simon. This is first time I see that tool..

    I plan to post a new thread with a proper title to address few more questions I still have. thank you all!
     

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