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Fester D Krepid Tutorial (WIP) Part 1

27K views 119 replies 24 participants last post by  niblique71 
#1 · (Edited)
As promised, I've begun work on a Tutorial for "Fester". I'll get as much of it done as quickly as I can. Fortunately for our forum friends I happen to be slow at work right now. So, over the next few days, hopefully I can have a more or less complete tutorial, or at least have the mechanism part completed.

NOTE: I will be updating every post as I find issues or grammar errors.

Here's the parts list for "Fester" as described in the 2011 prop Challenge

Vent Motor $2.99 Motion
12V Wall wart $.75 (Garage sale) Power supply
2" Foam scrap $.42 Hand carved Skull
Scrap 1 X 4 wood $.02 Motor Mount
Scrap 1 X 6 Wood $.06 Base
1/8 X 1/2 Aluminum flat $.81 (5") Crank arm/Linkage
3/16 round bar $1.25 (18" of 36") Pivots
Scrap 2 X 2 $.04 Main Lifting bars (Used 1' and Cut down
4 Yards CHeese Cloth $2.22 Clothing, Skin
1 5/8" Deck Screws @ .05 $.45 (Used 9)
Tiny Eye Hooks $.36 (Used 6 from an 200 pc assortment pack)
Small Extension Springs $.28 (Used 2 from a 100pc assortment pack)
Fishing Line braided $.20 (Used approx 4')
#8 washers $.46 (Used 10 from a pack of 100)
1/2" Cpvc $1.12 ( Used 40" froma 10' section) Arms
Ultra tiney wood screws $.07 (Used 7 from my own stock Price is a guess)
thin strip 1" scrap foam $.01 Teeth
Automotive Vacuum Line $.33 (4" off a 50' roll, had in stock) Retainers
3m Adhesive $.25 a few squirts here and there
Meduim Ceiling Hanger wire $.84 12' For Guards, Joints, Hands
4" wide Duct tape $.40 (Used 4') Hands
Latex Liquid n $.75 (Used about 1 oz, 40% sale at Micheals)
Cotten Balls $.15 (Used 15)
Scrap $1 store eyes $.17 (Cut one in half at 6 for $1)
10-24 machine screw $.10 (One from my own stock)
10-24 Lock Nuts $.14 ( 2 from my own stock)
1/4 20 bolt $.11 (One from my own stock)
1/4 20 Locknut $.11 (One from my own stock)
Small self Tapping Screws $.20 (4 from my own stock)
1" Pipe insulation $.04 (1" section for neck)
Soaker hose used $.15 ( used approx 1.5' ) X .03 rule
Sample can wood stain 2.33 Used approx 1/3rd (Price guess, High?)
Various Spray Paints $2.50 Less than 1/2 can total

Total--------------------$20.08

3/16" Rod-
First, a word about the 3/16th" rod. There are two kinds of rod that are considered 3/16", Hot rolled and Cold rolled. I use Hot rolled. It looks less shiney than the cold rolled and has an actual dimention that is larger than the cold rolled rod. Cold rolled steel is exactly what is sounds like. When they made it they let it cool and then rolled it as it was cool. This decreases the dimention of the rod and will not work for this tutorial since several pieces are "Press fitted" into the wood. Cold rolled steel is also harder, but more brittle. I ran into problems with this discrepancey when I did the NJ/PA MnT build of the One Armed Grave Grabber . So use the "hot rolled round rod found at HD or Lowes. It's NOT the shiney stuff.

Wood parts-
You can use any wood you want for this build, but I recomend Oak or some other hardwood for the main moving parts. When I originally built Fester, I took an old piece of scrap square 1-1/2" oak molding and cut it to the dimentions I wanted. It was tedious and Dangerous. I recomend finding some square oak pieces at a good lumber yard that measures 3/4" X 3/4" for your moving parts. If you are good with a Power Mitre saw, then you can make your pieces from a 1" X 4" oak stock. It happens to measure 3/4" X 3-1/2". I just cut it in 4 sections Longways, to make 3/4" square stock. Feel free to upgrade to aluminum square stock or Channel stock which can be found at HD or Lowes. For now I will stick close to the original build and use wood (Oak) since there would be many modifications needed to use aluminum for the moving parts AND it would be Much more costly.

Ok I started by cutting these pieces of 3/16" round stock to these dimentions (HOT ROLLED, NOT the shiney stuff).


Then I chamfered the edges to allow better insertion into the various pieces of wood, ESPECIALLY the press fitted ones.




In the Picture above there are a few things to Note: The wood shown isn't 3/4" square stock. it's 1/2" BUT the dimensions are correct otherwise. Use 3/4" square stock.

The two tiney pieces of wood are identical, I just turned one upright so you can see the two predrilled holes to mount them to the base plate.

The other pieces have a few extra holes for adjustment in case you get the geometry wrong. They also include some adjustment holes for your "Assistance springs". Fester is VERY weight dependant and a heavy fester won't work well or last very long. I needed to use a spring to help in the lifting motion which I will cover in future posts.

Note that the two pivot arms have rounded bottoms to prevent interferance with the base plate when in operation.

Also note, I HIGHLY recomend a Drill press for ALL of holes for the main mechanism. Any holes that are not perfectly plum will cause binding and/or excess slop that will prevent fester from working properly.

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Here is a picture of which holes will need to be press fitted. Press fitting reduced the cost AND reduced the "Slop" in the mechanism. Each rod shown is in a press fit hole prior to assembly. Note thier location and be sure to use the appropriate drill to get that ultra snug fit.


To make the press fit holes a 3/16" drill bit worked perfefctly with the Hot rolled steel rod. TEST the fit on some scrap wood (Same as you are going to use for fester)

To make the other "Looser" holes, I used a drill bit 1 size larger and tested the fit before continuing. I litterrally mean a drill bit that is 1/64th" larger than 3/16" (13/64") so that the remaining pieces can rotate freely with very little slop. TEST YOUR DRILL BITS with the wood you will be using to achieve a "Press fit size and a "Snug but loose" size before proceeding to cut and drill your pieces.
In the piece called "Spine" there is a press fit hole in the end of it to accept the neck rod. You can't see it in this picture but you'll see the neck rod in later pictures This is also a "Press fit" hole.

ANY resistance will affect fester since the motor is Pushed to the max. Find a drill bit combo that will work for you.

Here's a picture of the base plate with some measurements written on it to help you locate the pivot points. It also shows the location of the motor mount wood. It will be screwed into the side between the lines shown. You will have to mount your motor and linkage and run it without it being attached to get the desired motion. it sometimes takes two people to do this. I used 1-5/8" deck screws to secure the motor mount AFTER the motor is installed. More on that later.
 
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#3 · (Edited)
Fester Tutorial part 2

Here is another picture with the press fited shoulder rod and assembly layed out.




Note that 1/8" Automotive vacuum tubing and some washers are all I used to retain all of the pivot points.


Here are a few pictures of the main assembly including strings to make his head move left and right. Note that the shoulder assembly is allowed to pivot a little.


Note in the picture below there is a small piece of wood scewed into the spine at the top to limit the movement of the shoulders. I also had to lubricate the fishing line with some soap to get a nice smooth movement. The spring at the back is there to keep tension on the line as the mechanism cycles up and down. Also note the 1/8" ceiling wire protudeing from each side of the shoulder piece. I predrilled 1/8" holes at each end to accept the wire. If the wire fits too loose just put a few gentle kinks in the section that will be inserted into the hbole. I drill these holes at least 1" deep. The arms will be mounted here in a few steps.


To create the neck swivel block I made a piece of wood about 3/4" X 1-1/4" X about 3" long. I made this as long as I could and still drill all the way through it longways. I then sliced a thin piece of oak about the same width as the swivel block and about 1/8" thick by about 3" long. I used tiny screws (in predrilled holes) to attach it to the bottom. I then used my "Loose fit Drill bit" and drilled down the middle long ways. I attached a tiney screw at the end of the lever to attach the fishing line to to activate the head movement.

I used a washer between the spine and the shoulder. then put a piece of 1/8" automotive vacuum tubing on about 1" higer than the shoulders, then another washer, and then the head swivel block assembly.
 
#4 · (Edited)
Ok, So this tutorial is a new learning process for me. It truely is going to be a "Work in Progress". So be patient.

Here are a few more pictures which should be self explanatory.



In the picture above, note that I trimmed the top of the front pivot arm to make clearance for the string tensioner spring.
I also used my dremmel and a sanding drum to carve a rounded notch for the spring to set into at the top of the back pivot arm. This prevents the spring from occasionally falling to the side. It doesn't hurt anything when this happens as it resets itslef on the next cycle, However when it slips off it does make some "Unwanted" noise. I found it best to make this spring cradle.



In the picture below, Note the distance between the top of the shoulder and the bottom of the head swivel.
 
#6 ·
To set up your 4 rpm Gearmotor (vent motor), Check out Spooky1's VEnt motor connector and crank arm tutorial . Pay close attention to the part that describes how to make a crank arm for the motor.

I and others have found that quite a few of these vent motors don't work right out of the box. There are some connector tabs inside that sometimes aren't bent far enolugh to make contact with the motor. Hpropman and myself prefer to open the motor up and solder wires directly to the DC motor inside. this also allows an opportunity to add a little bit more lubrication to the internal gears. They don't spend much time distributing the little amount of white grease that they do put in these things. It could make your motor last MUCH Longer. I'll get to the dimensions of my linkage assembly tomorrow and edit this post.
 
#7 ·
Motor Mount and Linkage

In this part we'll cover the motor crank arm, linkage, and installation.

Here are the parts and sizes, and location/sizes of the holes for the crank arm and secondary linkage.


Once you have everything cut and drilled to the appropriate sizes, Assemble these parts first. Note that the crank arm and 1/4-20 jam nut were installed and tightened first on the 1/4-20 bolt, before threading into the motor. Also note that the 10-32 bolt and first nut were tightened all the way on the secondary linkage. This allows you to attach everything else loose at first to get your motor mounted in the proper position.


Next, Temporarily hold the motor mount and motor in a suitable position without the secondary linkage attached. Turn on your motor and get the crank arm to point straight down. Check for clearance with the base plate and the bottom of the crank arm. Don't get it too low, but as low as you feel comfortable with. While doing this you'll want to check to see that you have all of the motor holes in a position to get all 3 drilled into the motor mount. Check, Double check, Then hold the motor and pull the whole thing off while holding the position of the motor and carefully screw in the 1-5/8" deck screws to secure the motor to the motor mount.


Place the attached motor and assembly back against the base plate and check for clearance on last time. Note in this picture the 3/16" rod at the back end of fester. This is where your secondary linkage will attach to fester and the main crank arm. With the motor OFF, Temporarily attach the remaining linkage to the back of Fester and the motor mount. Use 2 washers and a piece of Vacuum tubing to hold the secondary linkage at the back of fester. This leaves just one Nut to add, but DON'T add it just yet. Get your 1-5/8" deck screws and get them ready by starting them in your predrilled holes at the bottom of the motor mount and be ready with your drill to run the screws in after we test for the proper motor position. While holding the Motor in the approximate position. Turn the motor on with the linkage temporarily attached. Slide the motor mount forward or backward to find a good balance of festers movement. REMEMBER! You will be adding ribs and a skull to him so LEAVE SOME ROOM at the botom of the cycle. Once your happy with his movement, Run in the Deck screws to secure the motor mount.


Now all that's left is to add that final 10-32 nut. Tighten it all the way at first, them BACK it off approc 1/2 turn. Fester should run Smoothly all by himself.
 
#8 ·
Here's a video of the basic mechanism in operation. Someone asked me a few days ago if they thought fester would be a durable prop and how many hours he had on him. The original fester now has over 50 hours on him without any sign of wear or strain. So I believe he'll be a durable prop if built properly.



Next we'll add the hands and arms and a skull.
 
#9 ·
To make festers arms, use 1/2 CPVC. Don't use regular 1/2 PVC since it is much thicker and heavier. Cut 4 pieces at 10" each. On one end of each piece drill a 3/16" hole all the way through. Then take your 3/16" drill bit out of the chuck and slide it in the holes you just drilled to use as a guide to drill your 1/8" holes. If the drill bit is Plum, it, helps you keep your smaller holes aligned with your larger holes.


Now take your 1/8" ceiling wire and using BOTH 1/8" holes make hinges similar to this. If you want your elbows to look more real, wrap a little bit of the excess wire around one of the pvc sections so the joints don't flop around as much. On a real person there is very little lateral movement at your elbows and yet your shoulders and wrists are essentially ball joints. That's why I left the shoulder and wrist joints as a 3/16" hole to allow for extra movement and posability.


here are the elbow joints


And a closeup of the wrists.


The Posable hands I made were just ceiling wire, cottenballs, duct tape and Latex.
 
#10 · (Edited)
Here is a picture of the finished basic prop without any covering.


Before you add any cheese cloth, Don't forget to make some guards to keep any material away from the motor and linkages. I just drilled 1/8" holes at strategic spots and inserted the 1/8" ceiling wire and custom bent to fit in.

To Finish him Off you can make ribs from ceiling wire or anything else that is light weight. To add a Foam skull (FOAM ONLY!!), use your dremmel and the bit that looks like a drill that can cut sideways. Just make a square hole that will allow the neck block to fit inside. Just do a little bit at a time and constantly check to make sure you are happy with the position of the skull. Also, I DID NOT Glue the skull on the neck block. I just made it a "press fit" so that you can change your skull without completely making a new neck assembly.

As you add cheese cloth, Check that you don't have any snags or restrictions FREQUENTLY. I added a piece, then ran fester to make sure there were no snags or binds. I did this COnstantly as I dressed him up. Also add some soap to the strings in the areas of the sliding eyehooks to help them move more freely. You might need to make some guards to protect the fishing line from being restricted. From here he is a custom build made by you. AGAIN, Constantly check to insure there are NO snags or restrictions ass you dress him out.

If you have too much shoulder movement and can't get a good head turn as a result, you can either lock the shoulder piece or make a different restrictor at the top or the spine. Or you can move the screw that holds the fishing line closer to the pivot point of the neck rod. Also note that adding fabric to fester restricts his shoulder movement. so by the time your done dressing him it might be a mute point and his shoulders might not move much. BUT it is a nice extra motion if you can position him in a way to make the shouders move when he's "Down low"

I'm sure there will be a TON of questions, so fire away and enjoy your Fester :)
 
#11 ·
Hi Greg,
Nice how-to! I'm going to start this project ASAP, using the materials you used. I'll build it with a view to converting to aluminum square stock, but I agree that it would raise the cost substantially. I wonder if PVC pipe could be used - the smaller OD pipe has a pretty thick wall and is quite rigid. It might increase flexing on the radiused ends, though. Oh yeah, did you use any lubricants on the moving joints?
Thanks!
 
#12 ·
Great thread and how to. I too would like to try to build this prop but with different stock.

Otaku
I was wondering the same about using PVC or metal instead of the wood. If you don't mind, will you lease take some pictures if you use something else besides wood for the parts? Pictures and what you did of the changes you made would be great. I am going to try different items too and I will update if I come up with something.
 
#13 ·
Will do, no problem. Regarding the wood components, I was considering drilling slightly oversized holes at the pivot points and inserting a 3/16" ID plastic or metal sleeve. I haven't used the hot-rolled steel rod before but in Greg's pix the surface looks a bit rough. Good for press-fitting but not for pivoting; the wood will eventually get reamed. Greg, what're your thoughts on this?
 
#14 · (Edited)
Actually, with a nice hardwood, and press fitting at leat one part of each joint, the mechanical slop was reduced significantly.

As far as the metal rods and the "Rust", the Wood tends to polish them up quite nicely as fester moves. I didn't lubricate the original fester bacause of the automotive vacuum tubing I used as retainers. I didn't want them to move or slide off. I but did plan on using an automotive (Thick) grease on the joints at some point. THis would add some rust protection for the rods as well. In the old days, people made very effective and long lasting wooden machines using just animal fat (lard?) for lubricant quite successfully. I did try white lithium grease (Spray on) on the second fester I used to make this tutorial. IT seemed to work quite nicely.

Obviously I would have built fester QUITE differently if I didn't have a $20 limit, so use your imagination.

Greg
 
#20 ·
I checked out the 1/2" PVC pipe tonight at HD, and even with the thick wall it flexes a bit too much. They had the 3/4" hardwood square stock at half off, so I picked up several feet. I have the use of the machine shop at my work, so making the parts will be easy. I'll get started this week.
 
#22 ·
Looking forward to seeing your results Gary. I had a thought though, since cost is no long as restrictive. If you want a relatively bulletproof prop You could replace JUST the shorter idler arms ( the ones that rock back and forth) with 1/2" aluminum or even 1/2" steel square tubing and use bolts for the spring assist mounts. Since those two pieces don't have any press fitted "Pivot" points, it should work fabulously. That way you can still use wood for the rest of the build (base plate pivots, and the spine are all press fitted and won't wear out the wood and are still relatively light weight).

Also, I was looking to replace the string setup for the head turn. I had in mind using a smaller steel rod and bending several 90 degree angles and mounting it inside two eyehooks on the back of the spine to make the head turn. I havn't yet found a suitable pivot point to activate the head motion. I'd love to do away with the fishing line due to the difficulty in replacing it in a few years on a fully dressed prop. Besides the strings really got in the way when dressing him. I had to be quite creative about dresing fester to get a smooth unrestricted motion.
 
#24 ·
Greg, in the pic where you show the parts that have press-fitted pins, the two dimensions - 3-3/4" and 9-3/8" - are those both referenced to the one end of the base plate? And are they measured to the 3/16" pin centers? I suspect "yes" on both questions, but wanted to be sure before I start cutting parts tomorrow. Thanks!
 
#25 ·
Powdered graphite doesn't attract dirt, and works well as a lubricant between wood and metal. John Deere combines use graphite as a lubricant on the hardwood blocks used as bearings on straw walkers - 12 inch wide, 10 foot long metal grates that reciprocate in the heart of the machine to separate the grain from the stalk. Those bearings last several years even with the huge lateral forces they're under during use.
You can get powdered graphite at auto parts stores or locksmiths - it's used to lubricate lock mechanisms.
 
#30 · (Edited)
BTW, I couldn't find the 3/16" steel rod that you spec'd. The HD site lists only one 3/16" rod, but it's zinc coated - probably won't work for this project. Could be it's just not on the site, I'll see tonight.

Edit: found the hot-rolled rods. Still a very smooth surface, just darker.
 
#31 ·
I'm getting ready to drill the press-fit and pivot holes in the wood blocks, and was looking at the pic of the two 2" blocks. It looks like the press-fit holes are not drilled at the center of the block, but are offset a bit. Is this just the pic, or is there an actual offset on these holes? Thanks!

Greg's reply:

The holes in the little base plate blocks centered left to right, but offset a high to give more clearance for the vertical pivot arms. Hope this helps,

Greg
 
#33 ·
Greg,
On the 6-1/2" block, you call out a press-fit hole with a 3-3/8" dimension. Is this dim measured from the pivot hole near the left end (in the pic) or from the left end of the block?
The reason I ask is that in the pic that shows the pins pressed into the holes, the 3-3/8" hole appears to be almost at the center of the block, which makes sense if the 3-3/8" is measured from the end of the block.
 
#34 ·
All pin hole measurements are given center to center. My graphics aren't that good. Assume the first hole is about 3/8" +/- inches in from the one end, then measure your distance from there for the other "on center" hole. If I'm not mistaken, all of the measurements above the pieces are rough overall lengths, and all measurements below each piece are center to center holes, assuming the first hole is a reasonable distance from the end.
 
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