Monthly Archives: January 2011

Aluminum Angle Bundle 14

I bought a bench vise off Craigslist and decided to put it to work bending parts I have been skipping because they are not 90 degrees.  You’ll notice the vise is not bolted down–I’m considering building a smaller workbench for tools.

The bend was 86 degrees–so small it seemed insignificant, but this picture captures it well.

I decided to use SolveSpace some more to draw parts that are presented in the plans at other than full scale and print them out full scale.

Aluminum Angle Bundle 13

Didn’t spend much time actually constructing anything on the airplane this week.  The last part I was working on is the flap detent angle.  This has notches where the flap handle rests at 0, 10, and 30 degrees.  Other people have added a detent for 20 degrees so I decided to give it a try.  I spent far too much time researching other peoples’ designs and noticed some people added nibs to more than just the 30 degree detent as shown in the plans.  Then I noticed a couple people mentioning the flap handle getting stuck in flight and it seemed to be due to the flap lever bending within the detent and getting jammed in–easily solved by modifying the geometry of the detent.  Needless to say I fantastically over-thought the part and decided to go even more extreme and draw it in CAD.

I found SolveSpace, a simple parametric CAD program that is very intuitive, and drew my own version of the flap detent angle.  Then I decided to cut it into aluminum on my wood-cutting CNC machine.  I was trying 25ipm with .03″ passes and it was estimated to take about 20 minutes to cut.  It was obvious I was cutting too fast–the tool was chattering like crazy so I quit and will cut it with the band saw.

I’m not counting all the time I spent messing around this week to my build time :-)

Here’s a video of me creating the part in SolveSpace:

Aluminum Angle Bundle 12

Was starting to feel worried I might end up with a build log without any pictures to prove that it was actually me building the airplane, so my wife helped me by taking some pictures.  Here I am wearing a Los Angeles Sanitation jumpsuit in an effort to keep the house a sterile environment with no exposure to aluminum flecks.  I also try to leave a set of old sneakers in the basement and take them off before coming up stairs.  Seems to be working fairly well.

There are a few things wrong with this picture.  Yes, I am actually using my head to dampen vibration on my band saw.  For some reason the top wheel has a fairly significant vibration that almost totally disappears once I touch my head to it.  The band dangling from my eye protection needs to be trimmed or adjusted.  I’m wearing my fancy ~ $3 Harbor Freight hearing protection–I decided when I finally get to fly the airplane I’d like to still be able to hear other pilots on the radio.

I have cut more parts but have no pictures to show.  I am trying to finish all the parts that don’t require bending and aren’t longer than 12″ for now.  I started preparing to cut the flap detent handle, but read about some people adding an extra setting for 20 degrees.  Also, builders have added nibs in an effort to prevent the handle from accidentally bouncing out of position.  These seem like a good idea, but have caused me to spend an excessive amount of time reading others’ build logs :-)

Aluminum Angle Bundle 11

I read about other people using tracing paper and spray adhesive to trace the plans and attach them to the metal.  For some of the parts without dimensions labeled in the plans this seems to be the most convenient method, so I decided to give it a try.

Here the tracing paper has been glued to the aluminum.  I think a somewhat weaker adhesive may have been better–once the paper touches it is difficult to move.

I was able to remove the tracing paper, flip it around and reuse it to make the mirrored parts.  Yesterday I started using some of the sanding attachments on my dremel tool to finish the edges–especially the inner radii.  This has worked well but it seems I’ll probably go through a sanding attachment just about every evening.  I have a bunch that I was probably never going to use, but I might look into getting something better like small scotch brite attachments.

Aluminum Angle Kit 10

I decided I better start wearing hearing protection so got some $3 earmuffs from Harbor Freight.  While there I also got some step drills.

I used the step drill to cut some small diameter circular cuts from some parts I was working on yesterday and they seemed to work well.

My current work flow is to find parts that don’t need to be bent that I have previously cut to approximate size and finish all the cuts.  One of these days I might figure out how to do the bends and I will add that to my skill set.

Aluminum Angle Kit 9

Snowmageddon 2011 hit and I was unable to buy a replacement blade for my band saw until today.  I bought the same metal cutting blade as before, but not without scouring the internet and a local machine shop.  I was really tempted to get something really nice like a bimetal or carbide blade (these seem to be around $30 online).  The local machine shop offered to weld a bimetal one for me for about $80–they aren’t really set up to do this for customers.  I was too impatient to wait for an online order, so I settled with the Lowes one again.

The new blade cuts just as good as before, but made an annoying clunking sound once per revolution.  I traced this down to a piece of dull metal sticking out in front of the teeth at the weld–this was smashing into my aluminum once per revolution.  I ground this off with my dremel tool and it was working great.

I started going back to parts I cut to size a week or so ago and finishing the more complicated cuts.

The curves were supposed to have a 1″ radius.  I found a conveniently sized container with the same dimension and traced that.  I need to figure out what everyone else uses for these types of cuts.  I did consider cutting out a bunch of circles on my CNC machine.

Its fun after reading other peoples’ build logs to finally be building parts I have seen before.  By the way, I have no clue how that yellow protractor thingy is supposed to help me.  I probably need to see someone who knows what they are doing use it.

Aluminum Angle Kit 8

Cut some more parts. Was prepared to do a lot of band saw work but it wasn’t cutting very well. Yesterday it was cutting like butter and today I had to apply significant force and it was hard to control. Then I remembered yesterday’s adventure. I was so pleased at how well the band saw was cutting I decided to cut through an integrated circuit (PIC microcontroller) for the fun of it. I think I learned my lesson…

Aluminum Angle Kit 7

These are now my longest band saw cuts.  The cut started scaring me with banging sounds.  After I was done cutting I re-tensioned the blade and adjusted the blade tracking.  The second cut had no scary sounds.  I cut just on the outside edge of my sharpie line and was within a blade width the whole cut.

These parts had a nice diagonal band saw cut.  The first part I cut the wrong angle but fortunately I left too much material behind and was able to fix it.  I was able to try out the vixen file on the cuts.  The secret seems to be to be very gentle with it to keep the teeth from catching on the edge.  Its amazing how much material is removed with as delicate pressure as I can apply.

Aluminum Angle Kit 6

My order from Wicks arrived today.  Most of the items are for the Sonex workshop in February.  My favorite item are these Andy aluminum snips–I’ve been referring to them as my man scissors.

Here are the rest of the items in the order with my steel ruler for scale.

Here is the vixen file along with the smaller, cheap file I have been using.  I couldn’t find much information comparing the vixen file to other files I might own, but I figured if its required they must know what they are talking about.  I tried it on some of my band saw edges this evening and it seems fantastic.

I did manage to get a few parts cut this evening.

Aluminum Angle Kit 5

Was losing my marbles this evening.  I dropped the sharpie I use to label the parts and wasted a bunch of time looking for it.  Then I left my cutting schedule that came with the aluminum between two pages of my plans without realizing it and spent a bunch of time trying to find it with no idea if it was on the floor somewhere or stuck in the plans.  I did manage to get some parts cut though.