Best way to widen the channel on a USGI M1A1 handguard?

[jtb33]

I have a USGI front handguard that I need to widen the 1/2" channel to be 3/4" so it fits on a newer manufactured M1A1.  I am not a woodworker, so likely don't have the proper tools.  Is there a "simple" way to widen the channel on both sides so that I can use it?

"Simple" may just mean sending it out to someone who has the proper tools to do it...

[anjong-ni]

Unless you really want to keep your original, the new one from A-O is pretty cheap.   ...Phil

https://shopkahrfirearmsgroup.com/firearm-parts/thompson-m1sb-23-horizontal-foregrip-27-23-tm1-pre.asp

 

Edited June 17, 2023 by anjong-ni

[StrangeRanger]

If you don't have access to someone with a router take anjong-ni's advice

[jtb33]

Thanks, but I already have the A-O handguard.  It's the one on the left in the pic I attached.  I'd like to use the USGI handguard (the matching USGI stock and grip do not require any modification to use).

I do have a plunge router that I've used for milling out 80% AR lowers with a jig, but not sure how I could use that for this and ensure that I get a straight cut along with the proper amount removed on each side.

Here's my Thompson SBR with the OEM A-O furniture.  Work done by Dan Block.  In retrospect, I would have ideally had him modify the part that attaches to it with the 1/2" part so it could use USGI furniture w/o modification - but that ship has sailed (would require extensive re-work, including removing the barrel).

Edited June 17, 2023 by jtb33

[TSMGguy]

Send the fore stock back to Dan for modification? 

[Dan K]

I am not very well set up for wood work but I have a full machine shop. I would run it on a Bridgeport personally.

[deerslayer]

If you have a router rable you can make a wedge that goes along the side of the stock to make the cut parallel to the existing slot.  Then just put in a 3/4 router bit and cut the slot.  

[johnsonlmg41]

Ditto on the Bridgeport. 

Setting up even a plunge router will be "the project" and starting and stopping in the correct location will be tough.  You'll either need a .75 cutter or have to move a smaller one and do two cuts, one on each side. 

I have both metalworking and woodwork equipment fortunately, but on a small part like this setup with the router will be over 1/2 hour and not precise.  Setup and completion on the mill will be within 1/1000 depth and width, complete in about 5 minutes with the current .25 cutter in it now.  The mill will be at least 5x safer to use.

[Grasshopper]

Hi All,

Oh yes.  I'm with Johsonlmg41 & Dank.  Playing "catch" with woodworking equipment can lead to giving out high-4's instead of high-5's for celebrations! .

Grasshopper

[Smith69]

On 6/17/2023 at 6:30 AM, Dan K said:

I am not very well set up for wood work but I have a full machine shop. I would run it on a Bridgeport personally.

Agreed,    This is a simple fix for anyone with a mill and a moderate skill level.    I would add that that to get a precise fit  either having the weapon there to test fit or an accurate measurement of the mounting width would be required.

[jojeep]

It took me a second to realize why he wanted to widen an original 1/2 to 3/4.

I had this issue once....the current 3/4 from Auto Ordnance is cut for the 16 inch Barrel and has a  wider Barrel area. The original 10.5 Barrel would look strange in the wooden horizontal grip with room on the sides 

I went through this when working with the Green Mountain 14.5 Barrel/welded Cutts