View Single Post
  #27   Spotlight this post!  
Unread 11-09-2012, 14:25
Mk.32's Avatar
Mk.32 Mk.32 is offline
Registered User
AKA: Mark
FRC #2485 (W.A.R. Lords)
Team Role: Engineer
 
Join Date: Jan 2011
Rookie Year: 2011
Location: San Diego
Posts: 770
Mk.32 has much to be proud ofMk.32 has much to be proud ofMk.32 has much to be proud ofMk.32 has much to be proud ofMk.32 has much to be proud ofMk.32 has much to be proud ofMk.32 has much to be proud ofMk.32 has much to be proud ofMk.32 has much to be proud ofMk.32 has much to be proud of
Re: pic: Team 3647: Gearbox

Quote:
Originally Posted by artdutra04 View Post
It sounds like you have access to a decent assortment of machine shop tools. If you have access to a surface grinder, a lathe, a Dremel, and an old worm out HSS end mill you can make your own hex broach. Here's how you can make a 1/2" hex broach:

1. Acquire a few inches of 1" or larger hex stock. Drill and ream a 5/8" hole through it, and add a set screw hole.
2. Take an old 5/8" HSS end mill. Cut off the flutes. Mount the shank into the hex tool holder above with about 1" sticking out.
3. Clamp down the hex stock onto the table of the surface grinder.
4. Take a light pass on the surface grinder.
5. Rotate the hex stock to the next face.
6. Repeat steps 3-5 until you have ground the end mill shank into a 1/2" hex profile.
7. Mount the end mill shank into a lathe with the hex profile facing outwards.
8. Put a cutoff tool in your Dremel tool. Turn on the lathe and Dremel, and hold the Dremel tool perpendicular to the lathe. The objective here is to cut a concave dimple with sharp edges into the hex profile.
9. Congrats, you now have a cheap hex broach that will work in soft materials like aluminum or plastic.

You can substitute in different sizes above to make 3/8", 7/16" or other size broaches.
Wow I never thought you could do that. Might give it a try
Instead of using a 5/8 endmill would just a stock of Tool Steel work?
Is just getting a good hex on the tool just a lot of time and patience on the grinder with careful measuring?
__________________
Engineering mentor: Team 2485: WARLords 2013-

Team President: Team 3647 2010-2013
Reply With Quote