Will a reamer self center in a worn oval hole???
Bud
original hole is worn in an oval shape. Will the appropriate size
reamer follow the original center of the hole? Should I use a rat
tail file to make the worn hole symetric in the opposite direction
before reaming?
I don't want to spend big bucks on all these fancy bushing machines
but I do have a good drill press and plan to buy specific bushings,
reamer and broach. Hole is approx. .063".
TIA
Frank Adam
wrote:
Reamer will center to it's easiest cutting position. So you'll end up
off center and with a headache without booze.. That's bad.
Yep, to be safe, file it near round, then use your pedestal drill to
drill it to 0.5mms of the diameter needed. Or closer if you are
confidnt in your drill's accuracy. Then touch up to the correct size
with a reamer. A clock bush generally needs a hole 0.03mm under it's
diameter.
--
Regards, Frank
dAz
> I want to install a bushing in a Telechron bearing plate. The
> original hole is worn in an oval shape. Will the appropriate size
> reamer follow the original center of the hole? Should I use a rat
> tail file to make the worn hole symetric in the opposite direction
> before reaming?
yes, use a fine rat tail file to round the hole to its true centre,
otherwise the reamer will as Frank said find the easiest way thru and
you end up with an off centre hole.
>
> I don't want to spend big bucks on all these fancy bushing machines
> but I do have a good drill press and plan to buy specific bushings,
> reamer and broach. Hole is approx. .063".
don't own a bushing machine, never have unless you count the jewelling
press I have for watch work, I just use a drill press or pedestal drill,
you can buy drills in metric steps of 1/10mm eg; 1.20mm 1.30mm 1.40mm
and so on I have a range of drills from 1mm to 10mm in 1/10th mm steps,
you can also buy the intermediate sizes like 1.25mm, 1.35mm, 1.45mm.
the bergeon brass bushes come in outside sizes of 2.00mm, 2.50mm,
3.00mm, 3.50mm and so on, with different pivot hole sizes.
so for example for most american clock plates I use a 3.00mm bush with a
1.00mm hole and either 1.50mm or 2.00mm height, use a 2.95mm drill to
drill out the plate after making sure the worn hole is centred
correctly, then just press the bush in, I prefer a tighter fit than the
recommended 0.03 press fit, I don't ream the plate hole before fitting
the bush so the 0.05mm press fit is fine.
I also prefer to ream the pivot hole to size rather than find a bush to
suit the pivot, because half the time the outside diameter of the bush
can end up too large and look quite bad.
Steve R.
"dAz" <dazb@zipDOTcomDOTau> wrote in message
news:4768be66$0$25819$afc3...@news.optusnet.com.au...
My method is a bit different from the above. I use centre drills, or stub
drills of suitable size. There is always part of the hole opposite the wear
that is still true. This can be used to properly align the centre drill. Use
only the pilot of the centre drill, which is quite rigid. Choose one with a
pilot that is bigger than the original hole plus the worn area. With the
plate clamped rigidly on a mill-drill or a lathe, drill through, taking care
not to engage the tapered part of the drill in the plate.. The hole will be
more accurately centred than possible with a file. The operation is also
faster. Now you can ream it out for a standard bushing, or turn your own in
the lathe. These days, a drill press (pillar drill) may have too much slop
in the quill for accurate work.
A stub drill can be used in place of a centre drill. They are just a short
rigid drill, and cannot wander like a longer "jobber" length one.
Steve R.
--
Reply address munged to bugger up spammers
dAz
> My method is a bit different from the above. I use centre drills, or stub
> drills of suitable size. There is always part of the hole opposite the wear
> that is still true. This can be used to properly align the centre drill. Use
> only the pilot of the centre drill, which is quite rigid. Choose one with a
> pilot that is bigger than the original hole plus the worn area. With the
> plate clamped rigidly on a mill-drill or a lathe, drill through, taking care
> not to engage the tapered part of the drill in the plate.. The hole will be
> more accurately centred than possible with a file. The operation is also
> faster. Now you can ream it out for a standard bushing, or turn your own in
> the lathe. These days, a drill press (pillar drill) may have too much slop
> in the quill for accurate work.
>
> A stub drill can be used in place of a centre drill. They are just a short
> rigid drill, and cannot wander like a longer "jobber" length one.
>
a grandfather clock plate is a bit big to swing in on my myford :)
actually I wouldn't mind buying a milling machine, they can be picked up
for quite reasonable prices these days and would be more accurate than
the drill press plus having the x-y bed.
I know a couple of guys in the trade that use a milling machine with
great success.
Steve R.
"dAz" <dazb@zipDOTcomDOTau> wrote in message
I too have a Myford! large clock plates can present a problem. My solution,
was to put the tailstock chuck in the headstock taper. I made duplicate
spindle nose on a number 2 morse taper. This let me mount a small faceplate
on the tailstock. It was usually possible to clamp a longcase clock plate in
position to drill out worn pivot holes. Note that it's best to use a drawbar
when the drill chuck is used in the headstock.
How I made the duplicate spindle nose:
In Canada, Busy Bee Machine Tools sell morse tapers with a soft, machinable
nose, and hardened taper. The soft nose had to be turned down a bit. I bored
out a piece of 12L44 leaded free machining steel to a tight force fit on the
nose of the morse taper. This was , of course, pressed on to the nose of the
morse taper. The part was then held in the headstock taper with a home made
drawbar, and machined.
Kettering
machining but never this small stuff.
I need to ask another question. Let's say I have a bushing with a
pivot bore hole at .061 and I need to enlarge is to .062. There are
no reamers this size that I'm aware of. Do I use a cutting broach??
I see in the timesaver catalog that cutting broaches are spec'd up to
___ in size. Does that mean they are slightly tappered. Do you
broach from both ends? Won't that result in a slightly houglass
shaped bore hole? Or does it even matter. The only reamers I've ever
used are adjustable up to the bore hole size you need but this is for
larger sleeve bearings
TIA, I'm just trying the understand the general approach.
The Baron
broach from both ends are not, it won't matter.
"Kettering" <n...@spam.com> wrote in message
news:kljjm3hoejpg4jocv...@4ax.com...
The Baron
called a rose cutter. It is like a mill with a center pilot. Most of
these have different diameters of pilots. I ground one down to use in
place of a KWM #3 reamer.
"Bud" <dav...@gmail.com> wrote in message
news:7ea5a10c-e18a-4de4...@i12g2000prf.googlegroups.com...