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Killbucket · February 5th, 2010, 18:34

Let's Make Parts From Scratch, 2010

This is an RC project part, but it could just as well be a jaw for a puppet, a grip for a BB-gun, or a widget, for a wudgette.
what is Is, isn't relevant.
What is, is some tips on hand-making parts without muss or fuss. And nope, we aren't using the CNC today...

Warning-all pics are 850 x638 for best clarity of what I'm doing here. Sorry if you have to left-click to see them whole...

I need some control arms for a custom project. I drew them in CAD, but these could have been hand-drawn full-size as well. Use what you have. Here, I've printed out my CAD outlines at 100% size. A Traxxas 8-32 rod end becomes part of each of these, I dropped it onto the sheet here for reference. The clear film is a hunk of Contact adhesive shelf paper.

I've covered the black ABS scrap piece that I'm making my parts from with the contact sheet. Do NOT try to use clear or Scotch tape- it won't peel back off easily. It won't, and you'll use TONS of time getting it all off. Stick with the clear shelf paper, or better yet, and paper masking tape, the blue stuff is best. I'm cheap, so this roll here will do just fine.

Here, I've cut out my printed layout, and sprayed the back with good ol' Super90 adhesive.

(High school memories dept: This stuff will hold a 90lb kid off the ground if you spray the back of his jacket with it, and have pre-coated a ready wall. Don't try this yourself)

Pressed into place center-first, your don't get bubbles under it. Center touches first, then let go of the ends. It will drop into place without fighting.

Be sure to cut off all that excess contact around the edges before moving on.

First cuts.
Rules of thumb:
1. Keep the parts in ONE CHUNK as long as possible.
2. Cut away all outside edges first.
3. Then make as many 'detail' cuts as needed while they are still easy to hang onto. We'll see this as we go along...
4. Save final separation of parts until last.

All of this is because larger parts are easier to hold and move around, and everything we need, isn't large...

I've cut away almost everything that isn't a control arm. while everything's still ONE chunk, I start making incisions into the part details.

These are called relief cuts, and they make cutting out these cavities possible.
BE EXTREMELY careful backing out of these short cuts. You don't want to twist the blade with the part while you do this.

All three locations are pre-cut into the bends in the lines.

Now the center slot on three of the arms are cut out. I just used the cutting edges of the blade like a grinder, and nibbled those whole areas out.

See how I cut across to the end of the cut that was previously made?

Repeating this process, you can 'chop out' these bits.

Zip, chop, cut.

Note complete absence of blood and gore. That's good.

More zippity-do-da.

If this happens, shut off the saw...THEN remove the but. Even if you have to do it over and over. Your fingers (....7,8,9,...?!?!?) will thank you.

Again, fine-tuning the shapes, using the blade to 'nibble away' up to the printed lines.

They're starting to emerge as parts...

This is the only 'SPOOKY" cut I had to make, the slot here on the fourth arm.
I had to cut it free of the main chunk to get 'at' this area, so I was left working a small part, up close and personal to a heartless blade.

Now I just have to cut away that area at the 'vee' shape there...

More relief cuts made.

Chop-choppity. See how the final cuts are all that's left here?
Note the spacing on those particular lines.
It's .03 inch, roughly what the saw removes during a cut.
In other words, make TWO cuts with ONE operation were possible.

Resist the temptation to peel 'em right away.
The little lines left on each one show me where to drill the holes for my pivot bolts.
Now how is that big rod-end gonna get fixed into pace?

You have to find my Mega Willy thread for that.

February 5th, 2010, 18:34	#1
Killbucket Trader rating Join Date: Jan 2007 Location: Citrus Heights, CA	Let's make parts, 2010 Let's Make Parts From Scratch, 2010 This is an RC project part, but it could just as well be a jaw for a puppet, a grip for a BB-gun, or a widget, for a wudgette. what is Is, isn't relevant. What is, is some tips on hand-making parts without muss or fuss. And nope, we aren't using the CNC today... Warning-all pics are 850 x638 for best clarity of what I'm doing here. Sorry if you have to left-click to see them whole... I need some control arms for a custom project. I drew them in CAD, but these could have been hand-drawn full-size as well. Use what you have. Here, I've printed out my CAD outlines at 100% size. A Traxxas 8-32 rod end becomes part of each of these, I dropped it onto the sheet here for reference. The clear film is a hunk of Contact adhesive shelf paper. I've covered the black ABS scrap piece that I'm making my parts from with the contact sheet. Do NOT try to use clear or Scotch tape- it won't peel back off easily. It won't, and you'll use TONS of time getting it all off. Stick with the clear shelf paper, or better yet, and paper masking tape, the blue stuff is best. I'm cheap, so this roll here will do just fine. Here, I've cut out my printed layout, and sprayed the back with good ol' Super90 adhesive. (High school memories dept: This stuff will hold a 90lb kid off the ground if you spray the back of his jacket with it, and have pre-coated a ready wall. Don't try this yourself) Pressed into place center-first, your don't get bubbles under it. Center touches first, then let go of the ends. It will drop into place without fighting. Be sure to cut off all that excess contact around the edges before moving on. First cuts. Rules of thumb: 1. Keep the parts in ONE CHUNK as long as possible. 2. Cut away all outside edges first. 3. Then make as many 'detail' cuts as needed while they are still easy to hang onto. We'll see this as we go along... 4. Save final separation of parts until last. All of this is because larger parts are easier to hold and move around, and everything we need, isn't large... I've cut away almost everything that isn't a control arm. while everything's still ONE chunk, I start making incisions into the part details. These are called relief cuts, and they make cutting out these cavities possible. BE EXTREMELY careful backing out of these short cuts. You don't want to twist the blade with the part while you do this. All three locations are pre-cut into the bends in the lines. Now the center slot on three of the arms are cut out. I just used the cutting edges of the blade like a grinder, and nibbled those whole areas out. See how I cut across to the end of the cut that was previously made? Repeating this process, you can 'chop out' these bits. Zip, chop, cut. Note complete absence of blood and gore. That's good. More zippity-do-da. If this happens, shut off the saw...THEN remove the but. Even if you have to do it over and over. Your fingers (....7,8,9,...?!?!?) will thank you. Again, fine-tuning the shapes, using the blade to 'nibble away' up to the printed lines. They're starting to emerge as parts... This is the only 'SPOOKY" cut I had to make, the slot here on the fourth arm. I had to cut it free of the main chunk to get 'at' this area, so I was left working a small part, up close and personal to a heartless blade. Now I just have to cut away that area at the 'vee' shape there... More relief cuts made. Chop-choppity. See how the final cuts are all that's left here? Note the spacing on those particular lines. It's .03 inch, roughly what the saw removes during a cut. In other words, make TWO cuts with ONE operation were possible. Resist the temptation to peel 'em right away. The little lines left on each one show me where to drill the holes for my pivot bolts. Now how is that big rod-end gonna get fixed into pace? You have to find my Mega Willy thread for that.