From: Robert Bastow <teenut@hotmail.com>
Newsgroups: rec.crafts.metalworking
Subject: Re: Anybody have tips for drilling/reaming 1018 CR?
Date: Sat, 24 Jun 2000 11:33:42 GMT

Todd wrote:
>

> 5)
> a) spot drill
> b) drill with 31/32" two flute 118 degree HSS drill (600 rpm)
> c) drill with 63/64" two flute 118 degree HSS drill (200 rpm)
> d) follow with 1.000 right hand spiral flute HSS reamer (200 rpm)
> Result was better but not good enough.
>
> What am I doing wrong?  Do I need TiN coated drills and reamers?
> I tried boring the hole but my lathe can't hold  the required 0.002"
> accuracy.
>
> Any hints will be greatly appreciated.
>
> thumbunny@home.net

Skip the 63/64" drill Todd..give the Reamer a bit more to "Bite" on.

Us an EP cutting oil rather than a soluble oil.

Speed is about right..increase feed.

All assuming your reamer is sharp!

teenut

From: Dave Baker
Newsgroups: rec.crafts.metalworking
Subject: Re: chucking reamer technique
Date: 04 Aug 1999 21:49:57 GMT

>From: Brian Evans <brian@uunet.ca>
>
>I've only ever used hand reamers.  I've ordered a chucking reamer to
>help me fix my rocker shaft problem, and I want to double check how to
>use it.
>
>My plan is to indicate in the work piece on the mill, put the reamer in
>the mill using a collect chuck, run the mill at about 75% of drill speed
>for the diameter (.636") and feed slowly using the table feed.  Am I
>close to right?
>
>Thanks, brian


The reamer speeds shown in textbooks etc tend to be optimised for production.
i.e. maximum output with reasonable tool life. Even then only up to about 50%
of the drilling speed would be used. For the DIY machinist just run them as
slow as you dare. I generally use 100 rpm regardless of reamer size and just
use a light but steady hand pressure on the quill handle to feed down.

You can get a load of cock ups with a reamer from spinning them too fast
(chatter and oversize holes mainly) but very few by spinning too slow. When I
started machining years ago (self taught mainly) I tried to make some bronze
valve guides. Last op was to ream in the lathe at 600 rpm or so and I got holes
up to 10 thou over !!! and awful chatter inside. Cocked a goodly number up
before I twigged the problem. Nice and slow and on long holes keep clearing the
swarf or they jam up. vertical reaming is better for holes more than 2 x D so
the swarf falls through.

Don't let the reamer dwell in the hole though if you want a good fit. Keep it
feeding and as soon as you are through the job, back it out fast and have a
measure. You can achieve quite a variety of tolerances on hole size when you
get a feel for how each reamer cuts. Run it through twice and another half thou
comes out without too much trouble usually.

Tip for a really tight fit with a reamer. Play a flame on the workpiece for a
few seconds before reaming and expand the metal. After reaming when it
contracts you lose a few tenths.

BTW - brand new reamers often have miniscule burrs on the flutes where they
have been ground which cause them to cut a tad oversize for the first few jobs
until the burrs wear down. (Especially when you are reaming aluminium or other
soft stuff) I give them a very light dress down the cutting edges with 1200
grit or similar or just run them through a few bits of scrap to test the
cutting size and bed them in a bit.

Ain't no big thing when you get the hang of it.


Dave Baker at Puma Race Engines (London - England)  - specialist cylinder head
work, flow development and engine blueprinting. Web page at
http://members.aol.com/pumaracing/index.htm

From: Robert Bastow <teenut@hotmail.com>
Newsgroups: rec.crafts.metalworking
Subject: Re: Precision Ground Dowels?
Date: Mon, 03 Jul 2000 16:01:59 GMT

peter michaux wrote:
>
> <raweich@my-deja.com> wrote in message news:8jppni$983$1@nnrp1.deja.com...
> > In article <TfV75.25421$NP5.716836@newsread2.prod.itd.earthlink.net>,
> >   "Gary Hallenbeck" <compressorguy@earthlink.net> wrote:
> > > There are taper reamers and straight reamers.  You want a straight
> > reamer of

> Thanks Richard.
>
> Do I hold the reamer in a drill chuck, a collet or do it by hand. They don't
> mention the shank size for "dowel pin reamers" in catalogues.
>
> Peter

Ref. Parallel Reamers.

"Hand" Reamers..the ones with a square shank, have a slight taper over the first
inch or so of flutes.  They are designed to be held in tap wrenches and cut on
the SIDES of the flutes, with a shearing action.

"Chucking" reamers have straight or morse taper shanks.  They have no lead in
taper but cut directly on the very end which has a small bevel.

Chucking reamers are held in collets, chucks, taper sockets or..best of all..in
a floating reamer holder.

Don't try to hand ream with a chucking reamer.  Be very careful "machine
reaming" with a hand reamer.

"Taper" reamers come in both persuasions..hand or machine shank.  They are used
for such taper applications as taper pins, Morse taper sockets, rifle chambers
and the like.  For best results use a floating holder.

"Bridging" reamers have a parallel section with a substantial lead in taper.
They are used to align holes in steelwork, prior to inserting "fitting" bolts or
rivets..a "Bodging" tool..used by hand or with hand held power tools.  One step
up from bashing a tapered drift through to align two holes.

Keep your fingers out of the holes!!  ;^)

teenut