MAKING A WOODEN GEARED CLOCK #6: Recut One Gear and Made a Sanding Jig

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Blog entry by stefang posted 11-21-2015 05:46 PM 1787 reads 1 time favorited 18 comments Add to Favorites Watch
« Part 5: Escapement Gear, Minute Gear and Idler Gear - Day 5 Part 6 of MAKING A WOODEN GEARED CLOCK series Part 7: Bits and Pieces - Day 7 »

Got a late start today so not much done.

Todays Work
You might remember that I messed up the escapement gear. The sharp tips of the teeth were very fragile and I broke a few out on the tip and back edges. I made a replacement today and found a good cutting technique that preserves the tips of the teeth and I also used a close to zero blade clearance auxiliary table for my scroll saw which maybe helped too.

Improved Cutting Technique
Instead of cutting fragile tooth tips close to the pattern line I angled the entrance and exit cuts away from the tooth tips as shown in the photo below A good reason to leave some extra wood outside the pattern. This worked very well and no teeth were damaged this time.

Sanding Jig
After the completing the replacement escapement gear I wanted to sand it to perfect round and thereby also get rid of the excess tip material. When cutting gears it is a good idea to leave the pattern lines on the very tip to leave a sanding target.

To get accurate sanding, A sanding circle jig was made for my disc sander. If I didn’t have a disk sander I would have used it on my lathe disk sander. The jig is simply a couple of pieces of plywood with the top two pieces cut at an angle of 15deg. on one edge and then glued to the ply base to form a dovetail slot.

A sliding piece was cut at the same angle on each side to fit the dovetail slot and holes are drilled in the slider the same diameter as the holes drilled in the gear center. The drill bit is used as an axel to keep the gear running accurately. It took about 15 minutes to make.

It’s just to mount the gear, shove it into the sanding disk until you just sand away the pattern line on one tooth, then the slider is clamped as shown and the gear is revolved by hand until all the teeth are sanded. Very simple and effective. photo below

A test to Confirm Smooth Running
After sanding the idler and minute gears I mounted them temporarily to a board to see if they would run smoothly. This was a worthwhile test. I could feel a little drag in a couple of places so I marked with a pencil where it was binding and then filed down those areas.Very little filing was necessary to eliminate the drag. I don’t know if this is normal practice, but I thought it was a good idea Photo below

That’s it for today. Have a nice weekend and thanks for reading.

-- Mike, an American living in Norway.

18 comments so far

View shipwright's profile


7094 posts in 2220 days

#1 posted 11-21-2015 06:35 PM

Well done on the DIY “wheel balancer”. I’ll bet it saved you a lot of head scratching later.
This all looks so good it makes me want to build one but I’m a rubbish plan follower, too independant by nature, and I also have way to many ideas for this lifetime. :-)

Looking just sweet!

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fibreglass trees.

View Jim Jakosh's profile

Jim Jakosh

16809 posts in 2527 days

#2 posted 11-21-2015 07:17 PM

Nice going Mike. I’d call them Mercedes gears!!
We area ll learning from you!!

Cheers, my friend….............Jim

-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!

View stefang's profile


15512 posts in 2756 days

#3 posted 11-21-2015 07:18 PM

I can relate to that Paul. I’m not much of a plan guy either, but unlike you I have way to few ideas and especially when it comes to anything like gears. This is what happens when you spend your working life as an office rat with no useful skills for retirement. I am spending the rest of my life as the perennial apprentice. I feel lucky and privileged though to be in the company of so many skilled and creative people like yourself. Some of it rubs off once in awhile.

-- Mike, an American living in Norway.

View stefang's profile


15512 posts in 2756 days

#4 posted 11-21-2015 07:27 PM

Yes Jim, the blind leading the blind. Remember, this clock might not work and then all my tips would be pretty questionable.

-- Mike, an American living in Norway.

View CFrye's profile (online now)


8581 posts in 1262 days

#5 posted 11-21-2015 10:28 PM

Mike, there is no doubt in our minds. It will work and work well!

-- God bless, Candy

View doubleDD's profile


5067 posts in 1465 days

#6 posted 11-22-2015 01:18 AM

I believe your ideas and sanding jig will bet you there. Can’t say what I would do in that case, only experience would tell. Looks like the battery back up mechanism is not needed yet. ha ah. I’m with you all the way.

-- Dave, Downers Grove, Il. -------- When you run out of ideas, start building your dreams.

View hunter71's profile


2696 posts in 2608 days

#7 posted 11-22-2015 03:35 AM

You’ll be making a Grandfather clock soon Mike.

-- A childs smile is payment enough.

View madts's profile


1663 posts in 1762 days

#8 posted 11-22-2015 05:55 AM

Keep up the good work. I like what I see


-- Thor and Odin are still the greatest of Gods.

View stefang's profile


15512 posts in 2756 days

#9 posted 11-22-2015 09:23 AM

If encouragement helps then this clock is bound to be a success. Thanks all.

Doug This is a grandfather clock (made by a grandfather).

-- Mike, an American living in Norway.

View Sylvain's profile


638 posts in 1921 days

#10 posted 11-22-2015 11:54 AM

The pendulum is probably adjusted in such a way that the escapement gear makes one revolution in 60” (or 1’). Then the gear train must reduce the speed to obtain one revolution in 12 hours on the hour indicating gear.
12 X 60’ = 720.
So the final ratio must be 1/720 which of course is easier to do with multiple gears.
Otherwise you would need for instance a gear with 5 tooth and the other one with 3600 tooth. Furthermore, the 3600 tooth gear would have a very very large diameter (in fact 720 greater than the small gear diameter) which is rather impractical.
Sawing the tooth on a 3600 tooth gear is a work I wouldn’t want to do.

-- Sylvain, Brussels, Belgium, Europe - The more I learn, the more there is to learn

View johnstoneb's profile


2105 posts in 1595 days

#11 posted 11-22-2015 01:28 PM

I mounted the gears in their position in the clock frame and ran them against each other and marked with the pencil and filed. This saved me the worry of getting the axle centers the exact distance on a separate board. Your scroll saw abilities make mine look like a beginner. I am enjoying your blog. Looking forward to seeing the clock run.

-- Bruce, Boise, ID

View stefang's profile


15512 posts in 2756 days

#12 posted 11-22-2015 02:00 PM

Sylvain Yes, I think the so called ‘minute’ gear must regulate the hour wheel. I’m looking forward to learning more about how all these gears work together, the ratios and the reason why they are placed as they are and how the idler gear assists the power train.

Bruce Thanks for the tip. I missed the obvious conclusion that the best test would be on the assembled clock itself. The rest of the work is mostly the pendulum and weight parts plus some spacers and axle caps.

-- Mike, an American living in Norway.

View Schwieb's profile


1792 posts in 2883 days

#13 posted 11-22-2015 03:17 PM

Coming along nicely Mike. I’ve had a desire to make one of these since I was a teenager. About time I get my Roundtuit going.

-- Dr. Ken, Florida - Durch harte arbeit werden Träume wahr.

View stefang's profile


15512 posts in 2756 days

#14 posted 11-22-2015 03:38 PM

Ken The parts are actually pretty easy to cut out. I think the main challenge is in the precision of the cutting and also the drilling. I’m not sure if my work is precise enough, but time will tell. On the upside, any parts that are bad can be redone.

Possibly such a project scares some people away because they haven’t got much knowledge of how clocks actually work (people like me). However with a plan, you just have to cut the parts from printed patterns and assemble according to instructions and then you learn how it works after you get it going. It is pretty enjoyable so far.

I remove the areas between the spokes on the gear first so I have something to hold on to. That goes pretty fast. I started out cutting one side at a time on the gears, but that got pretty boring so now I cut out the whole area between two teeth in one go. More entertaining, like the difference between driving a boring straight road for 1,000 miles or a winding road that keeps you alert and active the whole time,

I think that the most essential piece of equipment for a project like this is a good magnifier lamp with a florescent tubular bulb.

-- Mike, an American living in Norway.

View Jim Bertelson's profile

Jim Bertelson

3945 posts in 2586 days

#15 posted 11-23-2015 03:16 PM

I do not focus as close up as I used to, but without my glasses, I can focus on something perfectly without glasses at 12”. Nearsighted, of course. But I bought my magnifying lamp about 20 years ago, I think, and use it with increasing frequency. It is indispensable for removing splinters from hands…............(-:

......I also have my WorkSharp located right next to that lamp.

Very interesting, Mike, and I like your auxiliary table. It closely resembles my circle cutting jig for my band saw. Of course, shop gizmos and me are fast friends from way back…..............

-- Jim, Anchorage Alaska

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