Author Topic: Crown lapping tool  (Read 909 times)

Offline flatsguide

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Crown lapping tool
« on: September 18, 2024, 05:04:22 AM »
Nocked this tool out today and it worked nice. I drove it with a ball end Allen wrench that I cut the “L” section off. This works fine driving the tool this way as one does not need the drill to be perfectly lined up with the bore. The black guide is graphite impregnated Teflon and you can wrap tape around it to fi5 snugly in the bore. I used carpet spray glue to adhere the sandpaper ( 320, 400, 600 & 800 wet or dry) to the plastic bore guide. The bottom pic shows the template for cutting the sandpaper. Also, the bore guide is free to rotate on the mandrel.
Cheers Richard


















« Last Edit: September 18, 2024, 06:34:31 AM by flatsguide »

Offline Craig Wilcox

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Re: Crown lapping tool
« Reply #1 on: September 20, 2024, 06:21:15 PM »
Nifty tool indeed!
Craig Wilcox
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Offline flatsguide

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Re: Crown lapping tool
« Reply #2 on: September 22, 2024, 12:30:09 AM »
Belay that! I stated to wrap the sandpaper ‘to the plastic bore guide’ obviously that’s bs and I’m sure most of you caught that.
Craig, thanks for the compliment.
Richard

Offline Curtis

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Re: Crown lapping tool
« Reply #3 on: September 22, 2024, 07:20:20 AM »
Well though out as usual, Richard!

Curtis
Curtis Allinson
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Sometimes, late at night when I am alone in the inner sanctum of my workshop and no one else can see, I sand things using only my fingers for backing

Offline Dphariss

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Re: Crown lapping tool
« Reply #4 on: September 22, 2024, 06:29:33 PM »
Built one of these 10-15 years ago. Used lightly it once on pistol I made for my son to make it a little easier to load. I have a much steeper angled one for use as a crowning tool. If I remember I will get it out and take a photo. To me this goes to far down the barrel and makes the bore loose to far down from the muzzle.
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Offline flatsguide

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Re: Crown lapping tool
« Reply #5 on: September 23, 2024, 06:42:24 AM »
Thanks Curtis! Much appreciated.
 Dphariss, you don’t have to take much metal off when you use it. “Used lightly “ as you said. On Rice’s barrels, at least the ones I have come with a deep 45 degree taper crown so unless you shorten the barrel to get a nice radius crown your stuck with making a tool like this. Just a few seconds with 320 gives all the taper you need, the other finer paper remove very little metal but leaves a nice polish. If one thinks about it when you put a radius taper on a crown the final entry angle of the radius is only a few degrees, this tool has an included angle of 10 degrees.
By all means post your photo. I’m sure it would be interesting to see it.
Cheers Richard