Pinning

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Pinning:

(Note: This How To is respectfully dedicated to the memory of Ken Mosezar, an ACME member, friend and mentor.)

This approach uses a pin inserted in one part that fits in a related hole in a second part. This holds the two pieces together in alignment and allows you to mock up parts and modules of your project. It also creates a stronger joint. You can often use the pin to hold small parts for painting.

I usually use .032 brass rod for the pinning process:

IMG_1409-vi.jpg

I select a drill bit that is very slightly larger than the brass rod and drill the first piece. I usually create a starter hole with the sharp end of my Exacto knife: (Safety note: Make sure you really focus on this; the knife blade can slip off the piece and cut you.)

IMG_1451-vi.jpg

I super glue the pin in place using a length of brass rod that is much longer than I need. This makes handling the pin fairly easy.

IMG_1422-vi.jpg

When it sets up, I trim it to size. I remove any burrs and round off the end with a small file.

IMG_1423-vi.jpg

Next, I select the place for the hole in the second part. I am often able to press the two parts together, leaving a slight mark in the second one. Otherwise, I mark the second hole with a very fine point water soluble pen. I drill the second hole and test the fit with the pin. If all is well, I continue onward. If the hole is out of alignment for some reason, I usually fill it with super glue and an accelerator and re-drill the part.

Here are some pictures of the pinning I did on a recent 1921 Oldsmobile (Beverly Hillbillies) hot rod build.

Here, I used two pins for the engine and transmission:

IMG_1410-vi.jpg

These are the corresponding holes in the motor mount and transmission mount:

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Here you see the pins I used for the radiator and for the location of the radiator hoses on the radiator:

IMG_1413-vi.jpg

These are the pins on the engine for locating the carburetor and also for the other end of the radiator hoses. There are also pins for the water pump pulley and the ignition coil:

IMG_1414-vi.jpg

This view shows the pins I used for the windshield. I decided to do that because I wanted a good alignment and stronger joint.

IMG_1416-vi.jpg

This is another view of the front of the engine, showing the radiator hose pins and for the water pump pulley.

IMG_1421-vi.jpg

Edited by Steve_L

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Posted · Report post

This shows the pins and corresponding holes I used to mock up the exhaust pipes:

IMG_1428-vi.jpg

I don’t always use brass rod for pins; here it was advantageous to use short lengths of styrene rods. For the steering box, I selected the proper diameter to fit inside of the styrene tube I used to mock up the steering column. You can also see that the smaller styrene rod was used for a steering wheel pin.

IMG_1455-vi.jpg

It was important for this build to be able to mock up the steering box, steering link and the spindle arm in just the right positions. Here is how that turned out:

IMG_1456-vi.jpg

Assured that everything would fit together as needed, I proceeded to painting and final assembly. Pinning on this project gave me the cleaner build I was after and prevented final assembly drama.

On other builds, I need only to mock up the engine and transmission and the exhaust system with pins.

Again, the rationale for pinning is to hold two pieces together in alignment, allow you to mock up parts and modules of your project and create a stronger joint. You can often use the pin to hold small parts for painting. The outcome of my 1921 Oldsmobile would definitely have not been as good but for pinning. The investment of extra time was well worth it to me.

I trust these tips will be useful to you as we continue the quest to build better models.

Enjoy!

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Posted · Report post

This is a neat little trick, simple yet effective.

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Posted · Report post

Well done tutorial. I'm a pin addict myself ... anything I put together does so with a pin. :)

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Posted (edited) · Report post

I've been called a *****......Great IDEA!!

Edited by G Holding

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Posted · Report post

Nice !

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Posted · Report post

I like it and am going to use it.

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Posted · Report post

did this a few years ago and ill never go back to traditional mounting methods it works great for mirrors when they can be removeable.

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I've been using guitar string lately for pinning mirrors and other small parts and it seems to work good for me. After drilling a small hole, I cut the string with wire cutters and epoxy the string into the hole and then I do the same when I attach it to the body.

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A variation of your technique that I use: Stretched sprue - plastic tree held over a small votiv candle and rotated just until it becomes pliable. Then holding it away from the flame gently pull both ends. With a little practice you can control the thickness and lenth. The plastic is much easier to work with , I use fingernail clippers to trim after glueing into a drilled hole. Plus you can hold two parts together and drill through both for perfect alignment. If the pin hole is going to show, leave the pin long and just file the "show" side and it disappears. Note that some plastic tree stretches better than others, just experiment.

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Thats a well written tutorial Steve. I've been doing the same for years and its a excellent technique for strengthening and aligning things up.

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I started doing this a few years back on side mirrors and exhaust systems, but I use a piece of 30 gauge wire, works fine for me!

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Since everyone is giving pin material, I use about every type of round material on my bench. Copper wire, plastic, aluminum and brass rod, sewing pins and anything else that seems right for the particular part. The diameters vary by part also.

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Posted · Report post

Pinning makes a model fool proof. Thank you for the article.

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Posted · Report post

Great tip !

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Posted · Report post

Thanks for the tip! I had trouble attaching door mirrors, but with this tip, they should go stick now.

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