Author Topic: How do I get one of these triangular straight edges?  (Read 321 times)

Offline Mike K

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How do I get one of these triangular straight edges?
« on: April 06, 2021, 09:45:05 PM »
Or, rather, where?  Do they still make 'em?  Probably ridiculous to make oneself?

 

Offline mattinker

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Re: How do I get one of these triangular straight edges?
« Reply #1 on: April 07, 2021, 07:00:03 AM »
Mike

I found one in a second-hand tool dealer just north of Paris, un-scraped! extremely cheap! How about a piece of darabar? Not ridiculous at all to make one if you have a mill. When I bought mine, I thought about milling a 45 on one corner, I didn't need to as the dovetails that I will be using it on are 60.

Cheers, Matthew

Offline Mike K

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Re: How do I get one of these triangular straight edges?
« Reply #2 on: April 07, 2021, 09:15:52 AM »
Thanks Matthew.

Unfortunately, my only milling machine is the mini mill.  I plan to use it to true up my mini lathe.

-Mike

Offline Pete.

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Re: How do I get one of these triangular straight edges?
« Reply #3 on: April 07, 2021, 12:58:18 PM »
I tried to make one of those by milling 3 sides of a round cast iron bar. It bent like a banana.

I would look to getting one cast. It's not a difficult shape for casting.

Offline Mike K

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Re: How do I get one of these triangular straight edges?
« Reply #4 on: April 07, 2021, 03:51:43 PM »
And then scrape it in, using my 12"x18" surface plate for reference?

Offline awemawson

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Re: How do I get one of these triangular straight edges?
« Reply #5 on: April 07, 2021, 04:21:48 PM »
With a bit of effort you could slice that from square cast iron stock on a band saw, and hand file to an approximation before scraping as it's not a huge area.

Leave it a while after sawing to relax it's internal stresses before filing. Wet and dry on a bit of plate glass in decreasing coarseness's will get you even closer.

OK it's a lot of work but eminently doable with limited machining capabilities.
Andrew Mawson
East Sussex

Offline Peter Cordell

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Re: How do I get one of these triangular straight edges?
« Reply #6 on: April 07, 2021, 04:30:29 PM »
I made a short one a few years ago from a piece of old cast iron, that bent as i milled it.
So i did a little stress relief, heated it to 600c let it soak 2 hours lowered it to 500c let it soak 2 hours and so on
Was fine after that

Offline Mike K

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Re: How do I get one of these triangular straight edges?
« Reply #7 on: April 07, 2021, 08:24:09 PM »
All good ideas.  Thanks guys!

Offline WeldingRod

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Re: How do I get one of these triangular straight edges?
« Reply #8 on: April 08, 2021, 10:47:22 AM »
Sawing is a great way to start!  Definitely roast it as hot as you can manage before you start!

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