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I am looking for suggestions on making a core cutter.
I was thinking something like two pieces of 1/4 or 1/2 inch flat bar. I was going to use a valve spring on the pivot bolt to provide some tension. Now should i use hardened inserts where the lead wire goes through or would just a hole through both plates work?
Im assuming that tight fit to the lead wire is better?
Here is an example of what im thinking.
Attachment 273915Attachment 273916Attachment 273917
that actually looks like a good set up. I got tired of cutting and went to dedicated core molds.
Would the insert need to be hardened? If so do you do all the work like drilling, threading and grinding after hardening or before? Im assuming before.
Lead wire is pretty close to pure so hardening the cutting edges shouldn’t matter much. The wire should slide freely through the die.
I don't think either of my core cutters are hardened, but I don't want to put a file to them to find out. They're pretty simple in design.
Hope this helps.
Fred
How tight should the fit be between the cutter and the wire?
Just use the next size larger bit than you are trying to cut. It helps to have a little wiggle room.
A simple way to get hardened edges is to use a couple drill bushing. Your core cutter then is only limited to the bushings you have on hand. A single screw will lock each of them in place. Instead of the valve spring a lock washer of stack of beleville washers would be a more low profile nicer looking set up.
Like scissors or a paper cutter its a shearing action so they can be riding on each face for a good clean cut, with the bushing they could actually be slightly proud of the bars and reduce some drag.
The top bushing could be setup like a sprue cutter on a mould and relieved with a 82 degree counter bore to provide a true cutting edge.
Yours looks like the first core cutter that I made! I used 1/2” oil hardening drill rod for the bushings but did not harden them, no need, pure lead is soft as butter !
This is just the example of what I was thinking of building. Looks simple, effective and cheap enough to build.Quote:
Originally Posted by deltaenterprizes
Did you thread your insertsQuote:
Originally Posted by deltaenterprizes
It can’t be tight as the wire is not perfectly straight so needs some wiggle room.Quote:
Originally Posted by TrxR
Would a couple of these work for bushings?Attachment 274578
https://www.traverscanada.com/p-styl.../p/75-206-322/
or would you go up to the next size which is .2656"
Also ive got an old 4x52 belt/drum sander here would it work to surface the face of the cutter and bushing with the right belt? if not I will have to see if I can find someone with surface grinder or mill.
My first core cutter was a pair of pruning shears that I modified so I could install an adjustable stop for the lead wire. Pretty handy because you could cut right from off the roll using one hand.
Looks to me like a "take off" of the old Herters core cutter. They work wonderfully!
love my old core cutter it's like the Herters all cast
Ron Attachment 276152
What brand is that one ? It looks just like the Herters ive seen .Quote:
Originally Posted by RonIa
Made Mine like ammosmith's. I can cut cores wherever I want.
To directly answer the OPs question, the inserts do not have to be hardened. I have made all sorts of odd ball sizes for my Corbin cutter. Bore about .010" oversize in mild steel, slightly chamfer the side that the wire will feed from and polish with some SC paper. Works great but you will need a lathe to do these justice or know someone who does.
here's a picture of my core cutter think it was made by C&H
Ron Attachment 276553