Repurposing a Torx Bit as a Broach.

[astroracer]

I've been working on the brake set-up for my BadAst Astro Van build. This is a bracket I developed to hold the Wilwood Prop Valve I will be using.

With the valve bolted on. Clear access to both of the outlets on the bottom of the valve and it's not going anywhere. Once the lines are made and bolted in it will be pretty solid.


I ran into a bit of an issue with the prop valve placement. It is too low. The outlet for the front brake line I need to plug is to close to the bracket underneath it. I didn't think it would be a problem finding a low profile inverted flare plug to fill the hole but I have found nothing that will work. The regular plugs are to tall and I do not want to remake the bracket OR the hardlines, so.... I will make a low profile plug.
I puttered around in the shop the other night trying to figure out how to tighten the plug and came up with this. I bored a .173 diameter hole in a test piece of aluminum.

Then I used a short Torx bit to "broach" a hole for the driver. I started it with a few taps from a hammer to make sure it was straight then just pressed it into the test piece with the 4" vise.


Continued in next post.
Mark

[astroracer]

This worked great! I have some 3/8-24 threaded brass rod coming from McMaster Carr today. Hopefully the technique will work as well on the brass.

Making the inverted flare side is easy. A 3/16 drill and 90degree c'sink work perfect for that. Getting the "driver" side done will be the challenge.

I got the threaded rod and made a couple of plugs tonight. Went as easy as I was hoping. The Torx driver pushed in just as easy as it did with the aluminum test piece. I'm happy.
I got a foot of the 3/8-24 rod and used about half of this piece I cut off...

Dilled a pilot hole and ran a 90 degree chamfering tool into the drilled hole to make the bevel.

The beveled hole.

[astroracer]

For the broaching job, I drilled the hole out to .173 dia. That is the one I used in the aluminum piece.

I ran the fitting into a 3/8-24 nut so I could get the "broach" tapped in straight.

Just a couple of light taps with hammer got the broach started.

I then clamped the assembly into the vise and pressed away...

Continued in next post.

[astroracer]

Didn't take much to do the job.

I ran one into the prop valve.

And checked the clearance. We are good to go.


I made a couple of them while I was doing it. Now that I've made one the whole process only takes about 10 minutes.

Now, on to bigger and better things!
Mark

[DIYer]

Thanks astroracer! We've added your Broach to our Metalworking category,
as well as to your builder page: astroracer's Homemade Tools. Your receipt:

Broach by astroracer

tags: broach

[Peter Sanders]

Very well done! :-)

[astroracer]

Thank You Sir! I made a few more yesterday. A bit shorter then the previous attempts. They give me plenty of clearance now with no worries.


I don't know why these aren't available off the shelf... Not only do they provide for clearance I need but I think they look 100% better then those tall plugs do. My plug is on the right.

Mark

[McDesign]

Didn't take much to do the job.

I ran one into the prop valve.

And checked the clearance. We are good to go.


I made a couple of them while I was doing it. Now that I've made one the whole process only takes about 10 minutes.

Now, on to bigger and better things!
Mark

Lovely = got the same valve; had similar issues - I salute your solution!

[astroracer]

I feel honored to receive your praise in your 1st post. Thank You.
Mark

[Charron63]

Hi
If you take a sherical diamond stone tool mounted on 1/8th shank you can use a dremmel to dish out the face of your already hardened Torx etc bits and then they will cut like the grape ape...