3DoF Lexan C Leg Assembly Instructions

Last modified by Eric Nantel on 2026/04/02 16:15

"C" Leg Assembly Instructions

Updated December 20, 2011

Safety first! Wear eye protection and never touch a powered robot!

Note: Do not use Loctite or thread locks on the assembly. They are not necessary and may cause damage to the Lexan.

Important! You need to build three right legs (following these instructions) and three left legs (by mirroring these instructions)!

"C" Leg — Lexan Preparation

The lexan pieces have a protective covering that needs to be removed before assembly. When the laser cuts, the covering melts into the cut edge which can make removal difficult. If you gently scrape the cut edge with a flat blade screwdriver, the covering can easily be lifted and peeled off.

On smaller pieces the coverings can be more difficult to remove. If you have trouble you can gently scrape the cut edge, then use duct tape to lift the covering off.

For further information on lexan, see this page.

Lexan Preparation Lexan Preparation.
"C" Leg — Assembly
Step 1 / 18

Push the servo in through the lexan as shown. (Note: this is for a robot's right leg. You will need to mirror these steps for the left legs.)

Figure 1.
"C" Leg — Assembly
Step 2 / 18

Push the spacer lexan over the servo as shown.

Figure 2.
"C" Leg — Assembly
Step 3 / 18

Push the final lexan piece over the servo as shown.

Figure 3.
"C" Leg — Assembly
Step 4 / 18

Use the 4-40 x 3/4" hex screws with washers and nylon-insert lock nuts to secure the servo.

4x
4-40 x 3/4" hex socket screw
4x
4-40 washer
4x
4-40 nylon insert lock nut
Figure 4.
"C" Leg — Assembly
Step 5 / 18

Connect the bottom of the leg with a screw and a nut.

1x
3mm x 8mm Phillips screw
1x
3mm nut
Figure 5.
"C" Leg — Assembly
Step 6 / 18

You might want to use sandpaper to smooth off the edges of the bottom of the foot. It will be easier on the rubber end cap if you do.

Figure 6.
"C" Leg — Assembly
Step 7 / 18

Push the rubber end cap onto the end of the leg. It will come up over the screw and nut.

Figure 7.
"C" Leg — Assembly
Step 8 / 18

Peel the white cover off of the tape and press the tape onto the hinge as shown.

Figure 8.
"C" Leg — Assembly
Step 9 / 18

Attach the servo hinge as shown. Press it down firmly to ensure good contact.

Figure 9.
"C" Leg — Assembly
Step 10 / 18

Attach a ball bearing to the multi-purpose bracket as shown. Refer to Figure 10-1 for detailed information. Note: this ball bearing is part of the chassis kit or "C" bracket, if used.

Ball bearing assembly diagram
Figure 10-2.
"C" Leg — Assembly
Step 11 / 18

Attach the two multi-purpose brackets as shown, using two 2-56 x .250" screws and 2-56 nuts.

2x
2-56 x .250" Phillips screw
2x
2-56 nut
Figure 11.
"C" Leg — Assembly
Step 12 / 18

Attach the two "C" brackets as shown, using two 2-56 x .250" screws and 2-56 nuts.

2x
2-56 x .250" Phillips screw
2x
2-56 nut
Figure 12.
"C" Leg — Assembly
Step 13 / 18

Attach the "C" bracket to the multi-purpose bracket as shown. Refer to Figure 13-1 for detailed information.

Bracket assembly diagram
Figure 13-2.
"C" Leg — Assembly
Step 14 / 18

Attach the servo as shown, using either the snap rivet fasteners or 3mm hardware (shown). Make sure to route the servo wire as shown.

Figure 14.
"C" Leg — Assembly
Step 15 / 18

Attach the servo as shown, using either the snap rivet fasteners or 3mm hardware (shown). Make sure to route the servo wire as shown.

Figure 15.
"C" Leg — Assembly
Step 16 / 18

Attach the servo to the "C" bracket using the #2 tapping screws and the diagram below. Make sure that the servo is centered before attaching to the "C" bracket.

2x
#2 x .250" tapping screw
Hole position reference diagram
Figure 16.
"C" Leg — Assembly
Step 17 / 18

Attach the servo to the "C" bracket using the #2 tapping screws and the diagram below. Make sure that the servo is centered before attaching to the "C" bracket.

2x
#2 x .250" tapping screw
Hole position reference diagram
Figure 17.
"C" Leg — Assembly
Step 18 / 18

Attach the "C" bracket to the servo hinge as shown. Refer to Figure 18-1 for detailed information. Make sure to route the servo wire as shown — leave enough slack for the leg to freely move without pulling on the servo wire.

Hinge attachment diagram

You can now move on to the body assembly instructions.

Figure 18-2.
Tags:
Created by Eric Nantel on 2024/07/03 09:20
Copyright RobotShop 2018