This preview shows pages 1–2. Sign up to view the full content.
EML 4321 – HW #9 – Due 23 March, 2011
1. You are to broach a keyway for a square key into a 1” diameter drilledandreamed hole in the
center of a gear’s hub. The gear’s hub is 1.6” thick. The keyway is to be ¼” wide. The material is
200 HBN grey cast iron. The roughing teeth on the broach have a step of 0.005” per tooth and are
spaced 3/8” apart. The broaching is to occur at 80 SFM.
a. What is the average number of teeth cutting simultaneously?
1.6
0.375
=
4.27teeth
b. What is the maximum number of teeth cutting simultaneously?
If one tooth is about to leave there are
5 teeth
in the cut. Therefore the maximum number of teeth
engaged cutting is 5.
c. What is the average force required to push the broach?
22
2
,
1500
217557
1
4.27
0.005
217557
4
s
Nl
Specific cutting force K
mm
in
in
lb
teeth
in
tooth
in
==
⋅⋅
⋅=
1161 lb
b
d. What is the maximum force required to push the broach?
max
2
1
5
0.005
217557
4
in
lb
F
teeth
in
tooth
in
=⋅
⋅
⋅
=
1360lb
e. What speed (ft/min) should the broach be pushed at?
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview. Sign up
to
access the rest of the document.
 Spring '08
 Staff

Click to edit the document details