Posts from the ‘Wooden Gear Clock’ Category

Cutting the Wooden Gears – Part 2

Okay so in the last post I covered cutting these bad boys out with the scrollsaw.  In this post I will talk about using a bandsaw to cut the gears and using a scrollsaw / fretsaw to cut out the middle.

Using a bandsaw to cut the gears, is fairly simple to do.  With the pattern firmly affixed to the stock I first drilled out the center hole for the arbor and then made a few holes in the interior waste for the scrollsaw.  I made a rough cut around the outside of the gears to get them to approximately the correct size, having them close makes cutting the gears easier. I started by making V cuts just on the waste side of the lines, taking all of the left hand cuts all the way around the gear and then making all of the right hand cuts.  At the end of the right hand cut I would twist the gear to take out the remaining waste between the two cuts  giving it that curved bottom that is on the pattern.  Like with the scrollsaw this was not an optimum solution as it put a lot of tension on the blade and made a rather sloppy cut that I would have to clean up later.

Once I had all of the teeth cut out I took a scrap piece of mdf, drilled a hole exactly the size of the arbor required for each gear ( there are two separate sized arbors) and the pounded a small piece of brass rod into the mdf creating a jig for the gear.  I speared the gear onto the arbor trying hard to not blow out the back side of the hole.  Then taking gear and jig to the bandsaw, I clamped down the jig to the table the correct distance from the blade and then slowly spun the gear taking the top of each tooth off. I continued to rotate until I had all of the teeth at the correct distance from the arbor.

After doing this once, I thought to myself  “Self, I think there might be an easier way to do this”.

By boring the arbor and then spearing the gear on the scrap piece of mdf before i took it to the bandsaw, I could then clamp the jig down at the drill press and by rotating the jig I could drill out all of the Minute/Hour holes and have them even with each other.  I would also only have to worry about the spacing between the holes instead of both the spacing between the holes and the distance from the arbor.

 Holy Cow!  Did that work well.  So well in fact that I had another “Self” moment, remembering the problem I had with the gullet of each tooth.  On the bandsaw I was twisting the gear to carve out the bottom of the tooth, with only mixed results.  Still at the drill press I set the drill bit to just inside of the waste side of the line on the bottom of the gullet and plunged down, then rotating the gear to the next gullet repeating the process all the way around the gear.

This left me with a gear that had the arbor holes drilled, the Minute/Hour holes drilled and the bottom of each gullet drilled.  Now all I had to do was take the jig over to the bandsaw make a pass around the outside of the gear, bringing it to the correct diameter.  Once done with that I removed the gear from the jig and made the tooth cuts one on each side aiming for the hole I drilled in the bottom of the gullet.  After the second cut the waste popped right out and left me with a fairly clean cut, including the now perfectly round gullet.

Once I had this process worked out I started to gang up gears, doing two of them at a time.  Remember I have six of these to make and any process that was faster while retaining accuracy was a bonus.

The process for the pinions was pretty much the same except I used a drill bit that was exactly the same size as the round part of the gullet. 

Once I had the outsides all done I went back to the scrollsaw to waste out the middle of the gears.

Next time we will start looking at the spacers and all of the odds and ends before we get to assembling the sub groups.

Thanks for stopping by.

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Cutting the Wooden Gears – Part 1

Hello again!

First off let me apologize for the absence of posts lately.  I have had a severe case of Lifus Interuptus and with one thing leading to a BaZillion others I have been unable to sit down and put thoughts to screen, even now my Newfoundland is trying to see how much drool can fit in a keyboard. So sorry and hopefully the posts will be a little more regular for a while.

Sssoooo…  let us begin with the fun part of this project.  Cutting the gears out.

I am splitting this topic up into several posts.  Building six clocks, I tried out a couple of ways to cut the gears looking for the most accurate and efficient way available to me.  I perfectly understand that either a CNC or laser could cut all of the parts for this project in an alarmingly short time with superb accuracy.  Since I have access to neither of these VERY pricey tools, nor the desire to use them, I went with more traditional options.

The first option and the subject of this post will be using a scrollsaw.  I figured that since the pattern came out of a scrollsaw magazine and all, this would be a good method to start. Now I do not actually own a scroll saw, but my father does and he graciously allows me to borrow his tools… often. Thanks Pop!

Hopefully you have all of your plywood laid out in front of you, separated by thickness. If you are using a pattern from a magazine, like I am, you need to make copies, lots of copies.  Make more copies than you think you need.  It is always better to have more copies than you need than to have one too few, and then late one night as you are plugging right along, in the groove, and just whipping through these gears when suddenly you realize you have forgotten that last pinion or gear and now you have no more patterns.  You come to a screeching halt causing all of that precious mojo you have been building up to go right out the window along with several incoherent sentences worth of swear words. 

Okay so you have your copies and your plywood.  I recommend cutting out the patterns and sorting them by thickness and wood type as the pattern calls for several thicknesses of plywood but also several thicknesses of hardwood, the dials, runners for the weight line, caps, and the pallet, so separation is important. Once done sorting arrange the patterns on your stock trying to fit little parts inside the gears and leaving room around the outside to make cutting easier, Try to put the gears fairly close together to minimize waste.  Because you are cutting gears that have lots of teeth and holes there is a fair amount of waste involved and minimizing this as much as possible is always a good thing.

With a rough layout of the patterns, grab your spray adhesive and with all of the surfaces clean and free of debris, spray both the wood and your pattern.  You do not want the patterns moving on you. Quick Tip – a little mineral spirits and the adhesive will dissolve leaving your parts free of paper when all is done.  After giving things a few moments to allow the adhesive to tack up, carefully place your patterns lightly on your stock.  I recommend doing this for all of your pieces now instead of having to go back after some of the parts are cut.  It makes it a lot easier to keep track of which parts are done and which have yet to be cut.  After the patterns have been laid on the stock press down firmly from the center of each pattern smoothing outward to remove and wrinkles or air pockets, either of which will distort the patterns making fitting the clock together and getting it working all that much more difficult.

Patterned wood in hand, head to either your drill press if you have one or grab your favorite drill, electron powered or meat powered, and drill a pilot hole for your saw blade in each of the blank spaces of the gears. I also highly recommend that while the patterns are still fairly large go ahead and drill out hour, minute, and second holes in each of the gears.  It is easier with them in this state than when everything is cut out.  Just trust me on this one.

Saw blade picked out, I used a #5 crown tooth for the tricky bits and #9 reverse tooth for the teeth themselves.  Patterns affixed, and pilot holes drilled it is now time to find a comfortable position in front of your scrollsaw and start cutting some wood.  If you don’t have a scrollsaw you can use a fret saw, coping saw, or even a dremel I’ve heard.  They all cut pretty much the same way.  If you have a 1″ belt sander, it might be easier for you to leave the lines and come back later and sand to them. I don’t have such a tool so I went straight for the money cut.

Now you will probably break many blades, especially in the thicker material, but the best advice I can offer here is to go slow.  Take your time, DO NOT RUSH, the more accurate your cuts the less fitting you will have to do come assembly time.  I found that cutting the outside teeth first and then the interior pieces allowed me to work with a little more precision.  I don’t know if it was the saw I was using but even with shimming the insert flush all of the interior cuts would interfere with the smooth curves I was trying for on the teeth.  A word of caution: even though the gullets are not friction surfaces they still matter.  I had one gear that for some unknown reason my gullets were too shallow and I ended up filing all of them by hand to get everything to mesh, I had already glued pieces together and could not put it back on the saw.

Although some may see this as tedious, I found that plugging in an audiobook or music and just tuning out the rest of the world to focus on the very precise cuts to be very relaxing and even a little therapeutic.  With a little patients and a lot of attention to detail you will soon see a clock take shape, careful with contact surfaces they are IMPORTANT.

After completing my first set of gears this way, with perfect hindsight and the experience of the other methods, this was not my favorite method.  Granted I do not do tons of scrolling and my technique could definitely use some work, I found that even paying close attention to my lines I still ended up with a lot of variation in my teeth up to a 1/32″ sometimes and I then had to file until everything fit.   But that said it was a lot of fun and had that free hand feeling that is hard to get with power tools.

Next time… the bandsaw!

Making Plywood – Wooden Gear clocks

In the last post I mentioned I had decided to make my own plywood.  I initially had two reasons; one was that I a fairly large pile of Red Oak and Ash in my shop, and the second was that the thicknesses called for in the article, mostly 3/8″ plywood, was not readily available locally.

So I started by making a couple of test pieces.  To see how easy the process was and if I was going to have enough time to complete all six clocks.

  First I cut a board to about 3′ in length, flattened one face, and then one edge.

After I had a square edge from which to work, I then went to the band saw to start re-sawing these boards into 1/8″ thick veneers.

Then back to the bench to re-flatten the sawn face.  Back to band saw to cut another piece, back to the bench…  I think you get the picture.  It was about this time that I realised the Ash I was working with an absolute pain in the butt to work with hand tools, the grain was switching back and forth most of the time and I would have to plane one half of the board in one direction and the other half the other.  When you are trying to get everything to a consistent thickness, this is…  frustrating.

Any way, eventually I had enough pieces for one test piece in Oak and one in Ash, neither was much fun and took a lot longer than I had anticipated. Just to get the veneers!

Since I was aiming for a 3/8″ thickness I was going to use 3 veneers for each piece, alternating the grain perpendicular to each other for each ply.  I was not sure what the best glue would be for this application so I tried the two kinds I had in my shop.  Standard yellow glue and West Systems epoxy.

Doing a mock-up of the first 3 plys I came to the conclusion that there was no way I had enough nor deep enough clamps to really get good pressure across the entire surface.  So I made a press of sorts, I took two 2×6’s and cut them in roughly thirds, I also had some small pieces of 3/4″ mdf lying around so I ripped them to about 12″ wide and cut them to 30″ long.  On the bottom piece I screwed 3 2×6’s to one side with one on each edge and one in the middle, the middle one being the longer of the three.  For the piece that was to become the top I planed a slight arc to one edge of all three 2×6’s and screwed the bowed side to the mdf.  What this gave me was one really flat surface and one surface that had a bow in the middle allowing me to clamp my plywood in the middle using a total of six clamps and getting perfect pressure from the center out.

So I set my first ply down on the bottom platform and covered it in glue, also covering one side of the perpendicular pieces.  Then laying the glued faces together and tapping a small brad in each of the four corners and snipping it off just above the second ply, I applied glue to the other side of the perpendicular pieces and the bottom of the remaining veneer.  Setting the top ply in place and pressing it into the brads, keeping it from sliding around.

I then set the top platform on top of the stack and starting clamping the center 2×6’s together, trying to ensure that the pressure started at the center and pushed any excess glue out to the sides, not trapped in the middle.  I then put the outer clamps on.

After letting it percolate for twenty-four hours I took it out of the clamps and made my second test piece with yellow glue and Ash.  The epoxy seemed to work better and was a lot easier to spread, making less of a mess and a better bond. I then proceeded to flatten both faces and edges bringing it to a consistent thickness and size.

This whole process took a total of about three days when all said and done, and I came to the conclusion that it would take me too long to complete all of the plywood for the six clocks I was planning on making.  It also was REALLY work intensive without a thickness planer or drum Sander. Had I had either of those, I probably would have continued to make plywood for all of the clocks.  Instead I made enough for one clock, so it would look consistent.  My plywood could not be mistaken for the box store stuff I ended up purchasing.  That is also something I came to regret, poor glue bonds between plys, but we will get to that later.

I hope this was informative and in our next post we will start to look at the various ways I came up with for cutting out the gears.