Now, let's insert this rubber-lead combo into the racket.
As inside the racket is very rough, I needed "guides" to help push the insert in. Also because the rubber-lead combo is somewhat thicker than the hole, it just won't get in. But due to it being elastic, it'll expand back and hold tight when things are done.
The guides are thing and strong enough aluminum strips, longer than the length of the insert. In fact, only one strip may work. Using two strips can be a pain when pulling them out. When you pull out the guide, the rubber strip may come out along a little. To prevent this, use a finger to hold the rubber insert while pulling out the guide. BECAREFUL of any sharp edge of the guide.
Here's why the duct tape strip is needed along the length of the rubber-lead combo insert to prevent "abrasion":
When you use the guide, use it on the correct side. As you can see the protruding nails in there, I placed the guide on the nail side