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45 Deg. dovetail casting from Core Print

Sicardski

Aluminum
Joined
Dec 19, 2016
I purchased a 45 deg. dovetail casting from Core Print in Canada.
I have fly cut the surfaces and set it outside to age in the weather for a year.
After that I plan on fly cutting again and scraping to the final dimensions.

Question: what can I use or what SHOULD I use to transfer the 45 degree side for scraping?

Thanks in advance.
 
Just to note: leaving it outside will not do much other than cause surface rust.
There is a link to a paper floating around that dispels the myth.

Has the casting been stress relived? If not it will move around during scraping. The bonus here is that you do not have to wait a year.
 
Richard King recommends "ringing" the casting after rough machining to relieve residual stresses. Hang it up from a rope or non-binding hook, and smack it good with a hard plastic or rawhide mallet. Don't dent it, but you want nice sharp shocks. You're not going for surface peening, so you don't have to cover the entire surface, but it should be thoroughly "rung" like a bell.
 
From my experience with Coreprint's castings you will definitely want to high temp stress relieve them.

L7
 
Stress relieve

Thanks guys, I'll sent it out for stress relieving.

What can I use as a master to print the 45 deg. side?
 
Actually nicer if it is slightly more "acute" angle than the parts you need to spot. Lets you get in and do a good spotting. If you need a reference, use the other mating part. For rescraping the angle does not need to be exact.

I suppose if it did, you could make a reference piece.
 
With those core print wedges, if you machine the angle slightly under 45, those castings are pretty balanced that you don't even have to scrape the angle if you don't want. Just use it upside down and print with the bottom. Otherwise, just use your surface plate to print, as others said, the exact angle is not important.
 
Another wedge design to consider is Denis Foster's. Bonus is he supplies his heat treated, and if like my 36" SE I scraped from his machined casting, they scrape very nicely.

L7
 
Thanks for the info, I did not know that the angle was not critical.
I'm going to machine in slightly under 45 degrees and print on a granite plate of similar size.
I do like the old school method of aging the casting outside for a winter and summer.
I have my COre print straight edge in the rain gutters on the house right now.
 








 
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