Copyright 2006 - TeacherGeek - Ping-Pong Ball Launcher Activity - All Rights Reserved
Page
Ping-Pong Ball Launcher
™
Reaming Holes
A Slide Reamer makes it easier
to push or pull a dowel through
a hole.
*Having trouble getting a dowel
into a hole? Ream it with the
Slide Reamer.
The Loose Reamer creates
a hole that dowels can freely
rotate in and slide through.
A loose fit is typically used
to support axles, wheels and
pulleys. It is also used for
pivot points.
Learn how to
use a reamer
on page 5
Easy Engineering
™
Components come with holes that are the perfect size for a press
fit with dowels.
Dowels and Holes
A press fit is one where the dowel is fixed and not
able to rotate or slide once it’s in the component
hole. A press fit is good for creating rigid structures.
Press fits are good for
structural connections.
Press fits are good
for gears, pulleys
and levers that turn
together on the
same dowel (axle).
Slide Fit
Loose Fit
The Loose Reamer cre-
ates a hole that is larger
than the dowel.
The dowel moves freely
in the loose fitting hole.
This hole in the perpendicular
adaptor was reamed with the Slide
Reamer to make it easier for it to
slide to the middle of the dowel.
The crank and pulley are
press fit onto the same dowel
(so they turn together).
The link strip holes that the dowel needs to
rotate in were reamed with the Loose Reamer.
