# Any handheld cylindrical grinder/hone/bore?



## LEDcandle (Mar 12, 2006)

Was recently working on my mag mod, the MagDDL "Starglobe" 
https://www.candlepowerforums.com/threads/110551

Of course, boring the Mag body for 4-across bat configuration was part of the deal. 

I went to several machine shops locally (S'pore) but most of them were equipped to do car engines and didn't have bits/drills small enough to fit inside the mag body.

So I had to resort to hand filing, which took me many hours over a couple of days!  And its still not completely done.

What do you guys use to bore mags and other lights? A lathe? A mill? With what kind of bit?

Is there any type of handheld cylindrical grinder that's long enough and slim enough to grind the inside of a 4 or 5D mag or any bit in the market that I can attach to a drill/dremel to achieve that?

Advice appreciated. Pics/links/online stores/prices would be great! 

Thanks!


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## Vee3 (Mar 12, 2006)

A brake cylinder hone is what you need. Any auto parts store will have them for about $10 - $15.


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## LEDcandle (Mar 12, 2006)

I would think a auto machine shop would have that too but nooooo..... 
Unless they decided they didn't wanna waste time with my light.

http://www.houseoftools.com/content/houseoftoolscom/images/500/Products/K/K_D/K_D_265.jpg

So it's the 'arms' with stones that spin at the end? I don't really know how it works by looking at it straight off.


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## FRANKVZ (Mar 12, 2006)

Try here: http://www.eastwoodco.com/shopping/...7&itemType=PRODUCT&RS=1&keyword=cylinder,hone . You can probably get one cheaper at a local auto parts store.


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## LEDcandle (Mar 12, 2006)

Cool, Frankvz, thanks for the tip and pic


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## Illuminated (Mar 12, 2006)

Stone-type hones will load up extremely fast when used on aluminum - especially with anodized coatings like the Mag-Lite.

After much experimenting to come up with an effective way to port/polish aluminum cylinder head ports and curved aluminum intake manifolds, I finally made my own "flex hone" using something called an "overlap disc" (see Pic).







The edges of the discs will flex to conform to the ID of the workpiece. This one was 60-grit 1-1/2" diameter, and was made by Superior abrasives PN 13229. Though I couldn't find it on their website, this is similar:

http://www.superiorabrasives.com/CSpg35cat20.htm

I think I got (8) discs from a local industrial supply as samples to try out, since their minimum purchase quantity was 100 pcs as I recall. (Maybe a group buy might be in order?).

It has a threaded metal #8-32 center hub, and I stacked several together, separated by a #8-32 hex nut, on a long #8-32 screw as a mandrel. I screwed the assembly into the end of a 1/4" pull-dowell glued into the end of a stiff piece of reinforced 1/4" rubber hose to make it a "flexible snake" for using on my curved manifold runners.

The 60-grit was coarse enough to remove material fairly quickly without loading-up too badly.

For honing the Mag-Lite body, I would suggest a similar stack of 3-6 discs, only screw them into the end of a long 1/4" or 3/8" diameter steel or aluminum rod that can be chucked into a variable-speed electric drill. Rubber washers may also be used between discs to limit the flexing of the discs if needed for adequate surface contact pressure. The rod will of course need to be drilled and tapped on one end to accept the #8-32 screw.

Use a fairly low speed while working steadily back and forth inside the length of the bore, and remove it often to discharge the excess material being removed. Low RPM's will minimize the heat that will be generated.

This worked for my purposes, so I believe it should also work for effectively increasing the ID of the Mag D body.

Good luck!

John


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## LEDcandle (Mar 12, 2006)

Hey John, that sounds like a good idea. It'll take a bit of work to make the part but I think it might work. But that min qty thing sounds bad 

I wonder if other sanding/buffing/cutting discs might work. It's a really good idea to thread a 'string' of them on a rod and use that in a drill. :thumbsup:


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## Illuminated (Mar 12, 2006)

LEDcandle,

When I approached my industrial supply vendor, he was the one who told me that I could get an 8-disc sample pack to try when I told him that I didn't want to buy 100 just to see if they'd do what I wanted. It was several years ago when I did this, but he was happy to help me out.

Maybe you'll have similar luck? YMMV...

John

BTW - I'm not sure how you'd protect the tailcap threads if you try this method. maybe you could apply a few layers of masking tape to the threads for protection during entry/exit of the hone from the bore. You'll probably have to try it and see, maybe you'll come up with something better than that. Use your imagination - that often works for me. After all - neccissity is the mother of invention!


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