Dimple dies make a comeback. By Rick Junkermeier, WyoTech Motorsports Chassis Fabrication Instructor
A pattern of diminishing size dimple died holes in the door panel inserts of
an off road buggy built by WyoTech Motorsports Chassis Fabrication students and their instructor, Rick Junkermeier.
After WWII ended, and our servicemen returned looking for adventure, they
started the hot rod and custom motorcycle culture we all enjoy today. Without the ability to open a catalog and order parts, they had to improvise using the skills and techniques that they learned in the military. Parts such as AN-fittings and techniques like dimple die holes, both used in aircraft construction, found their way into our hobby.
Over the last several years, there has been a resurgence of the dimple die
technique, especially among rat rod builders. Companies such as Mittler Broth- ers and Poly Performance, whose dimple dies were used in these photos, offer sets of dies for use on sheet metal up to 3/16” thick. Combined with a set of hole saws or rotary broaches, these dies will allow you to layout patterns in a variety of creative designs to fit a variety of projects.
In aircraft construction, dimple dies were used to cut down on weight while
increasing the strength of the panel at the same time. The same is true in hot rodding. After laying out your pattern and drilling the holes to fit, put the female die on a shop press and lay the metal over the die insert with the male die above. Press them together until they touch, back off the press, and you’ll have an attractive and strong panel for your rod or chopper.
Bearing Installation Techniques By Tyler Gerrick, WyoTech-Daytona Motorcycle Instructor
Most bearings are installed with some press fit for retention purposes. This
press fit can sometimes be temporarily eliminated to make installation easier. To fit the bearing into a bore: Carefully heat the component that the bearing
fits into, and freeze the bearing. Use a heat gun, not a torch, for control. To fit a bearing onto a shaft: Carefully heat bearing inner race and freeze the
shaft. If force is needed to install the bearings, apply pressure in the right place or the bearing will be destroyed.
Caged Ball Bearings installed in to a bore: Make sure you are pressing only on the outer bearing race.
Bearings to be installed on shafts: Press only on the inner race. Be sure to use the correct sized driver to press on the race. Ensure that components are absolutely clean and free of any defects. Any damage, defect or pitting to the machined surface means the component must be replaced.
Drawn cup needle bearings used for camshafts and transmission gears have
a flat end and a rounded end. The bearing must be installed with the rounded end towards the bore it’s being installed into. If the bearing is installed back- wards, it will be destroyed.
Many NOS (New Old Stock) bearings have grease that solidifies over time. This solidified grease prevents free movement of the bearing internals and doesn’t lubricate adequately. Soak the bearings in clean solvent to soften the grease. Remove all the old grease and replace with new clean grease or as- sembly lube.
Finally, care and patience go a long way. Frequent checks during installation should be made to make sure the bearing is pressed in straight.
for smooth movement and lubricate before running. Do it Right, Do it Once!
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HRH.COM I FLORIDA HOT RODS & HOGS I aPRil 2012 25 Always check
Drawn cup needle bearings have a flat and rounded end
Panel being pressed with the dimple dies
Motorsports Chassis Fabrication students and their instructor, Rick Junkermeier
A pattern of diminishing size dimple died holes in the door panel inserts of an off road buggy built by WyoTech
Ball bearing to be pressed in transmission side door
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