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.