Using a drill press for bushing

Peter LoPresti

NAWCC Member
Aug 27, 2019
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Good evening all, I have looked at similar threads and I see many different opinions on this subject. I do most of my bushing repair by hand, but on larger plates etc I like to use a machine. I purchased a make-do KWM machine off of Ebay a few years ago, it was ok but for larger jobs and plates it is completely inadequate. I have used a regular KWM machine and love the work that it does but I do not own one. But also seen where you can use a drill press to do the work, and of course much cheaper. Now I don't really want to focus on cost. If a drill press is not a recommended way to do bushings, I will purchase the machine. So the question is, is a drill press a recommended way to go. Harbour freight has a 12 speed that can go down to 300 rpm, is that sufficient. Should the clamp/adaptor that Timesavers or Merritts has been purchased to clamp the work, or is there another method. I saw one person who uses 4 inch PVC under the work, which I use to hold movements up from my work bench. Any information would be greatly appreciated. Thank you for your time
Pete - From Hickory Springs Clock Repair
 

Elliott Wolin

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Nov 18, 2019
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I use a drill press but it has excellent runout, less than 0.002" if I recall, and the quill runs up and down very smoothly. This is important, as too much runout will cause the bushing hole to be oversized and the bushing will not have a good, tight fit (or it might even end up in the wrong place). Mine is a Delta light industrial drill press, I suspect cheap drill presses may have too much runout. Vibration can be a problem as well, mine has very little.

I doubt you can measure this in the store.

As for speed, mine goes down to 150 rpm, and the cutting action is slow and smooth. All my bushings fit nice and tight.

Finally, I clamp the plate after centering the quill over the correct part of the pivot hole using a KWM tapered centering point. Then I use a very rigid center drill to make a shallow dimple in the plate, just enough so that the reamer doesn't wander (I suspect the reamers are rigid enough that they wouldn't wander, but I guess I'm paranoid, and it only takes a few seconds to use the center drill).
 

Jerry Kieffer

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Good evening all, I have looked at similar threads and I see many different opinions on this subject. I do most of my bushing repair by hand, but on larger plates etc I like to use a machine. I purchased a make-do KWM machine off of Ebay a few years ago, it was ok but for larger jobs and plates it is completely inadequate. I have used a regular KWM machine and love the work that it does but I do not own one. But also seen where you can use a drill press to do the work, and of course much cheaper. Now I don't really want to focus on cost. If a drill press is not a recommended way to do bushings, I will purchase the machine. So the question is, is a drill press a recommended way to go. Harbour freight has a 12 speed that can go down to 300 rpm, is that sufficient. Should the clamp/adaptor that Timesavers or Merritts has been purchased to clamp the work, or is there another method. I saw one person who uses 4 inch PVC under the work, which I use to hold movements up from my work bench. Any information would be greatly appreciated. Thank you for your time
Pete - From Hickory Springs Clock Repair
Peter
It depends on your personal standards and personal demands of your equipment.

For myself personally, I am not happy unless the pivot is accurately relocated back to its original location in a timely fashion in both watches and clocks. Neither Hand bushing, Bushing machines nor a Drill press was able to accomplish this on a consistent basis at least by my hand. However, more importantly, none of these methods offered a practical solution to correct my own mistakes or those of others.

Thus I moved to a Small Milling machine capable of the size of work required. When properly utilized, it resolved all of the bushing issues as well as many other unrelated repair issues. In addition it offers the ability to diagnose and perform accurate depthing without purchasing a depthing tool.

To answer your specific question, The drill press had all of the same issues as a bushing machine but added an additional issue. The inaccuracy of the spindles and chucks increased bushing hole diameter reducing required friction fit of bushings to a uncomfortable able level. At least for myself.

Jerry Kieffer
 
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Paul Statham

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Hi having never worked on a drill press before curious to know how you do the depthing on one.
 

R. Croswell

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Hi having never worked on a drill press before curious to know how you do the depthing on one.
The short answer is you don't. You need an indexed table that can move the clamped plate front to back and left to right in increments of 0.001". Yes, you can add this to a drill press but unless you have a precision quality drill press the result will likely leave much to be desired. A small mill comes better equipped for this. I'll leave the explanation to Jerry, he has described the procedure here several times.

RC
 
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Peter LoPresti

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Aug 27, 2019
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Thank you for the answers I have received so far. Much to think about and contemplate. I would imagine that if I went with a milling machine, the quality of it would matter, same as a drill press, as Elliott mention run off and vibration. May I ask what kind of milling machine you have?
 

Jerry Kieffer

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Thank you for the answers I have received so far. Much to think about and contemplate. I would imagine that if I went with a milling machine, the quality of it would matter, same as a drill press, as Elliott mention run off and vibration. May I ask what kind of milling machine you have?
Peter

Of course the quality of any tool is an important consideration before purchase. However, if purchasing a Milling machine for general purpose work ,it is even more important to consider versatility. In other words, can it configure itself easily and efficiently to accomplish a task in an efficient and accurate manner. While not the only Small Mill on the market, I have found the Sherline to be the least expensive and cover all of the basis.

When bushing, the goal is to lock on to the original pivot hole location. Pivot holes are ever so slightly larger than pivots and tend to wear a path that is slightly smaller than the pivot hole diameter per first attached photo. When bushing on the Mill, I install a Gage pin, Drill shank or whatever in the spindle that is a snug fit to the original pivot hole per second photo. The slides are moved per RC`s explanation until the pin will drop into the hole.
At this point the spindle is raised and the desired reamer installed. Since the Mill is very Rigid, the initial part of the reamer becomes a boring bar in effect, until a centered circumference is achieved and then becomes a reamer for the rest of the depth. No filing or hole adjustment is required or desired for this procedure.

A poorly placed bushing will either have no gear tooth backlash or excessive tooth backlash. By placing two suspect arbors next to each other between the plates, excessive friction or other issues can generally be felt or heard when the wheels are spun. To correct the issue in a Mill, the old bushing is removed and the movement with the two arbors are installed in movement holders in the Mill per third photo. At this point, a staking punch, bushing wire or what ever has that a pivot size hole is installed in the mill spindle and setup to engage the pivot in the removed bushing hole again per third photo. You can now move the Mill slides slightly until the two arbors rotate with the least amount of friction as done in a depthing tool.
Once depthing is found, the movement holder is designed so that the lower plate can be dropped and the arbors removed. The spindle can now be raised, next size larger reamer installed and the new bushing hole reamed maintaining depthed location.

In my personal experience, when I purchased my first mill it cost less than all of the tools it replaced as well as out performing those tools.

Jerry Kieffer


18408E0C-56CE-48B6-96CF-0FFFB8DB6477.jpeg DCFD291C-4066-4196-A57B-D4D8DCE4C943_1_201_a.jpeg 35352508-F60F-4EAD-8021-4833ACF29D22_1_201_a.jpeg
 
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Willie X

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Peter,
My answer would also be no. But a drill press can be used to improve the quality of your hand bushing, assuming you have learned how to, mark, file, nibble, or whatever, to center the new hole on the old center.

A drill press is good for is making the new hole upright when hand bushing.

After you have gone just past the point where the hole is round and back to it's original center. Place the plate on three precision blocks or spacers (red wire nuts work well) and make sure the table is properly adjusted.

Using the correct 'D' cutter and a very light touch, you can true up all your pre prepped bushing holes at one time, no clamping is needed.

This only takes a few seconds per hole and gives you a noticeable improvement when fitting your bushings by hand. Any speed around 250-RPM is good.

Most drill presses are strong enough to finish the job by pressing in the new bushings. All you need is a good size nut or washers to back up the plate and a 3" piece of steel rod for the pusher. If your table is flimsey you can back it up with a good hardwood block ...

No matter what you cobble up with your drill press (if we'll adjusted) the results WILL be faster and with some improvement over hand bushing by eyeball alone.

Willie X
 

James Lucas

NAWCC Member
Aug 25, 2020
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Peter,
My answer would also be no. But a drill press can be used to improve the quality of your hand bushing, assuming you have learned how to, mark, file, nibble, or whatever, to center the new hole on the old center.

A drill press is good for is making the new hole upright when hand bushing.

After you have gone just past the point where the hole is round and back to it's original center. Place the plate on three precision blocks or spacers (red wire nuts work well) and make sure the table is properly adjusted.

Using the correct 'D' cutter and a very light touch, you can true up all your pre prepped bushing holes at one time, no clamping is needed.

This only takes a few seconds per hole and gives you a noticeable improvement when fitting your bushings by hand. Any speed around 250-RPM is good.

Most drill presses are strong enough to finish the job by pressing in the new bushings. All you need is a good size nut or washers to back up the plate and a 3" piece of steel rod for the pusher. If your table is flimsey you can back it up with a good hardwood block ...

No matter what you cobble up with your drill press (if we'll adjusted) the results WILL be faster and with some improvement over hand bushing by eyeball alone.

Willie X
Willie, Please explain the nibble process. I've been using a file but am always looking for a better way.
Thanks,
James
 

wow

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James, Willie is referring to a reamer such as the one below when he mentioned the “D” cutter. It is shaped like a “D” so you can cut on one side only. After determining the direction of the wear on a pivot hole you can cut or “nibble” in the opposite direction of the wear until the hole is round, thus, moving the center of the new bushing to the correct depthing center where it needs to be. Once the hole is round, you cut in all directions (in a circle) until it cuts through the plate. Then you’re ready for the new bushing.
 

James Lucas

NAWCC Member
Aug 25, 2020
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James, Willie is referring to a reamer such as the one below when he mentioned the “D” cutter. It is shaped like a “D” so you can cut on one side only. After determining the direction of the wear on a pivot hole you can cut or “nibble” in the opposite direction of the wear until the hole is round, thus, moving the center of the new bushing to the correct depthing center where it needs to be. Once the hole is round, you cut in all directions (in a circle) until it cuts through the plate. Then you’re ready for the new bushing.
Thanks for the info. I don't understand how the hole becomes round when "nibble" 180 degrees from the wear. In my mind I vision an egg shape hole. What am I missing?
James
 

shutterbug

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You 'nibble' opposite the wear, not to make the hole round but to cause whatever you cut the hole with to center and not follow the wear. Precision equipment of some sort is highly recommended, but some guys have used a broach for years with good success.
 

James Lucas

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Aug 25, 2020
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You 'nibble' opposite the wear, not to make the hole round but to cause whatever you cut the hole with to center and not follow the wear. Precision equipment of some sort is highly recommended, but some guys have used a broach for years with good success.
Okay, got it. Thanks shutterbug..
 

Dells

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Oct 18, 2019
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Okay, got it. Thanks shutterbug..
I followed Jerry’s recommendation and watched I video he done and purchased a small mill and although I am in the uk and Sherline are American I managed to find someone in the uk that sells them and purchased the clock bushing supports and the work a treat, although I mostly work on torsion clocks I do have to bush other clocks sometimes, not only can you bush clock movements on the mill you can do so much more , I think dedicated bushing machines are a ripoff, so much money for something that will only do one job when a small mill can do so much more and for quite a bit less money, my Warco WM12 cost me £750 a new bushing tool is probably twice that.
Just my opinion Dell
 

James Lucas

NAWCC Member
Aug 25, 2020
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I followed Jerry’s recommendation and watched I video he done and purchased a small mill and although I am in the uk and Sherline are American I managed to find someone in the uk that sells them and purchased the clock bushing supports and the work a treat, although I mostly work on torsion clocks I do have to bush other clocks sometimes, not only can you bush clock movements on the mill you can do so much more , I think dedicated bushing machines are a ripoff, so much money for something that will only do one job when a small mill can do so much more and for quite a bit less money, my Warco WM12 cost me £750 a new bushing tool is probably twice that.
Just my opinion Dell
Thanks Dell, I live in Vista CA where Sherline is located. I'll check it out..
James
 

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