Been pretty busy...

Greetings all,

  I have not been able to work much on the clock recently.  Between work and going to a blacksmithing convention last weekend and doing a boy scout blacksmithing demo this weekend, not much progress.  I'm hoping to get some work in this week.

Just a quick post...

Unfortunately, due to work and Halo 3 (mostly Halo 3) I have not gotten as much done as I would have liked to over the past week.  However, I am thinking of taking a few days off next week just to get some smithing time in. I have about 1/2 of the teeth cut at this point.

On a note related to that, I am expecting that I will have remake the gear.  I, in many ways, was fully expecting that before I even started.  My experience has shown that when creating a more complex part for the first time, it takes several attempts to get it right and there are a few things about this gear that may not work.

So why am I proceeding?  Quite simple, gear cutting practice.  If I screw up this gear, no problem.  It gives me a chance to really perfect my gear cutting.

First tooth!

  I got a bit of time in with the clock today.  I started by doing some completion work on the chisel that I will use for cutting waste between the teeth.

  This is the method that I am using to cut the teeth.  It starts by cutting the sides of the teeth.  These cuts are about 1/2" deep to give an idea of the size.



This is followed by gently heating the area. I have to be very careful because it would be very easy to burn the teeth away.  After heating, I use the chisel to knock out the waste.  This picture shows what it looks like unheated.  It is hard to tell from the photo but the backside of the chisel is flat so that the bottom of the gap between the teeth will be flatter and need less cleanup filing.



After cutting the first tooth, I went ahead and started cutting the remainder of the teeth.  So far, I have about 10 teeth cuts made.  I hope that by the end of this week, all the cuts will be made and I can pop out the waste.  This is followed up by cleanup filing.  Also notice to the right of the photo is a spot where I popped out the waste material.  It really worked like a charm.



On a final note, as I was marking out the teeth, I did notice a few small problems.  Hopefully it will not cause me problems but even if it is unusable, I am planing on cutting all of the teeth just for the practice.

Gear cutting has started

Today (betwen the many rainstorms) I was able to finish centering up the gear.  I am hoping that everything will be okay.  It looks pretty good but I will not know for sure until it has to rotate against another gear.

After getting everything centered and cleaning up the outer diameter, I decided to start cutting the gear.  I did not have the camera with me due to all of the rain but I will take some pictures during the next session.  This particular gear is going to have 100 teeth.  The start of the process was to use a divider to create 10 equal arcs on the gear.  From there, those were divided in half.  Each of those arcs should contain 5 teeth.  I am able to use the divider to evenly divide this into 5 pieces.

So, after placing a small mark, I use a small wooden pattern to mark the cutout for the teeth.  After scribing a small line, I then took the hacksaw and cut the sides of the tooth.  The waste material is still in place.  If the rain stops and I can get the forge going, I will then heat the gear up a bit and use a chisel to knock the waste material out of the way.

In all honesty, if not for the rain, I probably could have gotten a lot done on the gear today.  Oh well...

On a final note, I did make a minor mistake.  The clock that I am reproducing only had 96 teeth on the main wheel, not 100.  The 96 is probably because it was easily evenly divided to very small numbers which makes it easy to mark for cutting.  I just made a little goof as I was thinking of my original wooden clock.  It really is not that big of a deal.  Extra teeth on this wheel will not hurt me.

Finally setup my new toy...

  Well, last Christmas season I had gotten a new Grizzly belt grinder/buffer.  For those not familiar with them, they are essentially a large vertical belt grinder/sander with a buffing wheel off to the side.  It is used by a lot of people for making knives but it reality it is just a good, all around grinder.  Well, because of some bad stuff and being busy, I never set it up.



  To give an idea of size, the belt is a 72" loop.

  Today I finally got around to putting it together.  Other than some poorly written directions combined with bad illustrations, I soon had it up and running.  The first thing I tried it out on was my gear from last week.

  For the gear, I need to smooth the outside down before I can gut the gear's teeth.  I will also need to true the gear up to be a perfect circle (at least on the outside) when rotating around the arbor.  Up until now, I was planning on doing it with a lot of filing and some work on the old bench grinder.

  I cannot say enough how surprised I was by the efficiency of the Grizzly.  It really smoothed the outside down fast.  It is not trued up to a circle yet, I was just removing some of the bumps.  But this will really be a labor saver.

  For those few that have been following my blog for more than a few months, you know that it is very important to me that I make this clock using mostly traditional techniques.  In the middle ages, the work of the Grizzly would have been done my a traditional grinding wheel.  Although I have one being held by a friend for me, I will still need to make an assembly to hold the wheel and allow me to power it using a foot pedal.  That is a way's off.

  I hope that before the clock is complete, I get a chance to finish one of the gears using the traditional grinding wheel.  But until then, the Grizzly sure is fun...  :)

Things getting a bit hairy...

  I forgot to mention that I did get about 15 strands of horse hair for the clock.  A friend gave them to me last Friday.  These will be used to suspend a portion of the clock that needs to swing freely.

  Anyone know how much weight a single horse hair can hold?  Maybe I will have to google it....  :)

Gear mounted

  On Friday, I managed to get some more work in.  I decided that since I did not have dividers that were big enough to verify the wheel was centered, I put small extensions on the end of the divider and I was able to use this to verify everything was nice and centered.

  I started with bending the tabs over to secure the hub,spokes and wheel together.



This turned out to be a nice tight fit.  Next came the arbor.  Since the arbor is square where the gear attaches, I need to use a square punch.  To line it up, I drew lines down the center of the spokes.  Then the corners of the punch were placed on the lines to properly center it.  This picture shows the placement of the punch.



After placing the punch, I then used that as a guide to tap 4 divots in the hub.  This would allow me to properly place the punch after heating.  The divots marked the corners and I used that to start punching the hole.  A bit more of "beauty shot" is shown here.  This is after the first 2 or 3 punches.  Coal dust has gathered in the punched area.  Look for the darker square in the middle of the fire.



When I had punched the arbor about 25% through the hub, I placed the hub over a bolster plate (flat piece of metal with a hole in it that matches what you are trying to punch) and I was able to easily push the remaining material out.

Finally, after punching the arbor hole, I put the new gear on the arbor to try it out in the clock frame.



If you look carefully, there is a square washer on both sides of the gear on the arbor.  This helps to keep it perpendicular to the arbor.

It looks pretty good.  I need to tilt the gear a bit.  However, the gear does seem to be a lot more centered then my first attempt.  The variance seems to be at a maximum of 1/4" with the average being under 1/8".  That is about the best I can really hope for.

After doing just a bit more cleanup, the next step will be the grinding of the outside to get it nice and round.  After that, maybe I can finally start cutting the gear.

As an added note, in future gears, I will punch the arbor prior to mounting the hub and spokes in the wheel.  I had to constantly restraighten the spokes while I was doing the punching.