Shafts and Attachments Flashcards
These transmit motion and power from one machine to another
Shafts
These are used to locate parts precisely
Keys and keyseats
Axial grooves manufactured into attachments and shafts are known as
Splines
Key stock is manufactured to this tolerance
A plus tolerance (oversize)
Key-stock material
low to medium carbon steel (AISI 1020 cold drawn)
Bar stock is made to this tolerance
A minus tolerance
Sizes up to 0.75” -0.002
Sizes 0.75 to 1.5” -0.003
Rectangular keys are also known as
Flat keys
Square keys are recommended for shaft sizes up to
165mm (6.5”)
Rectangular is recommended for larger sizes
This key is used when the shaft keyseat is a different size than the hub keyseat, and also align machine parts
Offset key (stepped key)
This key does not require a keyseat in the shaft, uses friction from the set screws upon it
Saddle key
This key is equal length to the keyseat, and less than the width of the hub
Boxed (blind) keys ex. Buried, Pratt and Whitney
Similar to boxed keys, but are 2/3 in the shaft, 1/3 in the hub (also sizes they come in)
Sunk keys (sizes from No 1. 1/2” long by 1/16” wide to No 34. 3” long by 5/8” wide
This key has a tight fit in the keyseat, sometimes secured by screws and allows some axial movement of the hub
Fixed feather
This key slides in a keyseat with the part along the shaft, prevents the rotation of one part on the other
Sliding feather
This key secures the component firmly to the shaft with no set screw
Tapered key
The standard taper for tapered keys
1 in 96 or 1/8” in 12”
Metric ratio is 1 in 100
Woodruff keys with a diameter larger than ___ may have their ends flattened
1.5”
The last two digits in a woodruff key give this
Nominal diameter in eighths of an inch
ex. #406 = 06x1/8 = 3/4
The digit(s) before the last two digits in a woodruff key give this
Width of key in thirty-secondths of an inch
ex. #406 = 4x1/32 = 1/8
The width of the key is ___ ______ the nominal diameter of the shaft
one quarter
How do you find the key length
Same as the shaft diameter
End mills produce this keyseat
Profile
Horizontal milling cutters produce this kind of keyseat
Sled runner or runout
Keyseat alignment has these maximum tolerances
- 25mm (0.010”) for offset alignment.
0. 10mm (0.002”) in a distance of 100mm (4”) for angular misalignment
How is the depth of a keyseat measured
Diametrically from the bottom of the keyseat to the opposite side of the shaft
How are parallel keyseats cut in bores
Enough to accommodate half the height of the key plus clearance
End mills used to cut keys are called this
Slot cutters
What tolerance do end mills have on the diameter
+0.0000 to -0.0015
What is the method for cutting key seats in attachments
Hand-broaching
How much does each tooth protrude on a broach
0.003” (0.07mm) further than the preceding tooth (last 3 are the same)
Each pass cuts to a depth of 1/16”
Keyway broaches are furnished with this amount of rake
8 to 10 degrees
What are the classes of fit for keys
Class 1 is a clearance fit
Class 2 is a relatively tight fit
Class 3 is an interference fit
What are the clearances for the key in a keyseat
0.005” above, 0.002” on the sides
When should adhesives not be used for keys
Temperatures above 93 C