Cutting, facing and finishing brass tubes and stainless steel rods for clock arbors

Notch

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May 19, 2018
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Hi all,

First of all, I’m here as I went searching for my answer to this current job I have to complete for my wooden clock.

I don’t have any “machines” as such - well not cnc or lathe.

I have a drill press on which I’ve become competent enough to drill my wheel and pinion holes square and centre, a bench grinder with a coarse and medium wheel, grinders/cutters, a Dremel, and the rest is all wood working (saws, hand drills, files and such)

I’m somewhat familiar with the requirements of the rods and tubes I want to make for my clock as I spent many years building model helicopters. Here I worked with prefabricated parts (spindles, shafts, clutches, pinions and gears etc) but it introduced me to the kind of exacting work that you are all familiar with.

So my challenge is that I have a desire to cut, face and finish my clock’s arbors and arbor assemblies as meticulously as possible.

I’ve been cutting the rods and tubes with a variety of tools - a mitre box and razor saw (only good for the brass tubes), Dremel cutting wheels (can’t do longer arbors without making an angled cut due to the tool profile, so parts need to be cut again to square off the face), grinder with cutting wheel - fast and effective if not particularly accurate!

I then take the slightly oversized rods to the bench grinder and attempt to square the face with the guide plates (this creates a somewhat square face with the grinder scores running in one direction.

Then I’ll take the part and use a needle file to trim the dags by hand, chuck it in the hand drill or drill press and use a combination of sand papers to ease the edge, smooth the face and get an initially satisfactory “ground” surface.

I have to reverse the parts in the drill and this leads to a less than ideal mid-section where it’s double polished and sometimes damage from the chuck (attempted to fix by using grease-proof paper to protect the part in the chuck.

Finally I experimented with various cutting and polishing compounds in the drills aiding the buffing with a leather belt or polishing cloth etc.

The result I got with my main arbor - a 3/16” stainless steel rod was quite pleasing - not mirror finish but when I look at the surface with a loupe the result is very fine and probably more than enough to minimise friction in a mechanism like this clock, where the interface between the wheels and pinions (raw wood on wood) will no doubt be the biggest factor.

The 1/8” arbor rods are more fiddly but I’m trying much the same process with these.

The biggest area of annoyance is that the only way I can get a squares off face is to drill a correct hole in a piece of scrap, press the part into it and use a file across the face where the rod projects slightly so it is flush with the scrap.

This will give me a pleasing square end but there is almost no way I can put a regular chamfer or bevel on the edges (say on the drill press with a file or in a hand drill against the bench grinder) they can look ok but will all be different.
(Note that only in a few places will these ends be visible so I’m thinking that a polished square face with edges lightly eased will have to do.)

The tubes are easier to cut and square but have their own challenges.
I’m cutting them as square as possible, using 1200grit on the bench and rubbing the ends to finish, remove dags and burrs. Then I’ll use a round needle file to clean up the inside edges but I don’t know if I’m introducing scores to the inner surface that may interfere with the rods.

By chucking them I’ve been able to spin them and insert a round piece of 1200 wrapped around my needle file.

This seems to produce a reasonably clean finish but again it’s not ideal and the polishing is tricky because they are short.

I guess I’m here to ask you guys what my options are to get as good a result as possible (without investment in machines - time yes and effort) or if I’d be best to take my parts to a machinist and get them “done” - couldn’t be too expensive though I guess even a minimum job will be more than the need demands.

Here is a pic of the set I’ve cut but not finished (some more than others)

I would love to hear any ideas and excuse me for the Long essay! If anyone’s actually read it many thanks in advance! I hope I’m making sense and done a reasonable job with what I have on hand.

66bd6c6e7a6495ed5b72012caba91d7b.jpg
 
I guess the kind of finished look would ideally be something like these:

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Squared off

Or eased

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Your best option would be to look for a small mini lathe.
 
Welcome to the forum Notch. First you have come to the wrong place if you don't want to buy machines.....just kidding, We LOVE machines.
Besides investing in a mini lathe as suggested. If you have a good drill press, you could purchase an x-y table to give you better control. You can do simple turning operations that way.

If you don't already have a jeweler's saw, that would also be a good investment and not expensive. There is a vast selection of blades with fine teeth that work well on thin walled brass tube.

Other than that you can make simple jigs and fixtures to hold / guide the work piece and or the tool, like it sounds that you have been doing.

David
 
If you drill a close fitting hole in a wood block , you could use it as a bearing to steady the rod/tubing. Chuck the rod/tubing in your drill and dress the end of the rotating shaft with a file or Dremel with a stone. You can chamfer the end in this way as well.
 
In a time long ago, before I got my first lathe, I used to face small diameter rods and tubes by chucking them in the drill press and lightly pressing them against a grinding stone that was flat on the table and being moved back an forth. Its a little tricky to get the feel of quill pressure and stone movement but you can achieve fairly accurate length and square with this method. Then pressing the part against some abrasive cloth or paper to achieve the desired polish.
However, a lathe is the best tool for this type of work.
 
In a time long ago, before I got my first lathe, I used to face small diameter rods and tubes by chucking them in the drill press and lightly pressing them against a grinding stone that was flat on the table and being moved back an forth. Its a little tricky to get the feel of quill pressure and stone movement but you can achieve fairly accurate length and square with this method. Then pressing the part against some abrasive cloth or paper to achieve the desired polish.
However, a lathe is the best tool for this type of work.

This sounds promising! Thank you.


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