Hi Chaps,
I was wondering if anyone had bought or knew how to fabricate a hand crowning tool? This is a hand held tool that cuts an 11 degree chamfer onto the end of your barrel cutting the (I hope) perfect bevel for accurate shooting.
These tools are for sale in the USA but I have not seen one here, also as I am on a budget is there a cheap way of making one? Sorry if this has been done to death but before I start chopping a barrel I want to cover all options. (Just to add I have no lathe, access to one or the skills to use one without losing at least one of my digits).
Thanks in advance.
Holy balls! That is the tool I was looking at on a US website........eye wateringly more expensive here Thanks Chaps but out of my league until I sell a kidney. Is no one selling a knock off version?
This is the first time I have seen an angle specified ... 11 degrees?
In the absence of a specific cutting tool could you use an 11 degree taper and valve grinding paste/polish ... asked in ignorance as I have no experience of this operation. I remember someone recommending a brass dome head screw for doing the same job?
Cheers, Phil
I tried a brass screw Phil, but didn't get very good results.
I now use a 12mm ball bearing wrapped in 360 grit paper if hand crowning --- sticky backed DA paper works best.
Or if I have the barrel in the lathe I use the spherical end of a Mini engine pushrod wrapped in 360 grit paper mounted in the toolpost chuck.
After the 360 grit I use 1200 grit then polish.
All the best Mick
I think GGGR uses a marble? The tool is far too expensive to justify buying for me
I have a countersink bit that a drill bit passes through, instead of the drill bit a piece of brass rod and you've made your own
http://www.screwfix.com/p/erbauer-co...U3gaAh1a8P8HAQ
Thats damned clever Butt....thanks for sharing...
I think the 11* came up after some intense experimentation with bench rest rifles in the States some years back, but I believe it's since been found not to be too critical Maybe you could fine a woodworking countersink tool that could be adapted, you're only dealing with mild steel.
I also use a half inchish ball bearing, you can use a dome headed brass screw but it takes absolutely ages & just seems to be a good way to ruin a perfectly good screw, I only tried it once...
1/2" ball bearing glued to a nut which is just threaded and glued onto a bolt.
Used as a drill bit with a blob of valve grinding paste, cleaned and then use autosol polish.
Thanks Guys, some interesting tips....the people selling the tools claim its very scientific, I am starting to have doubts about the critical 11 degrees!
There are different types of crown if you do research.. i think the 11° one is called a target crown.
For me its a ball bearing epoxied to a quick change bit holder. Chuck it up in the screwgun and stick a bit of 1200 lapping paper on the bearing and whizz away.
Thats fir finishing though... i do mine on the lathe 😆
Donald
I've done them with a sharpened pencil and some wet and dry paper! I now use a fine pointed stone on my dremle type tool then polish with fine W&D then solvo polish. Check by putting a cotton wool bud down the barrel if it snags when you pull it out it needs more work.
Si
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