Any Suggestions For Cutting/Shaping Polymer?

[Hiknefer]

I purchased a handguard with a built-in flashlight (model KR-016B) for my Arsenal SAM-7K AK pistol. The handguard was supposed to be compatible with the SAM-7K but the back of it isn't shaped properly to fit in the receiver slot. I called K-Var and they told me the design had changed at some point and the description on their website was never updated to reflect that fact. I would still like to use the new handguard but I'll have to re-shape the polymer protrusion that fits into the receiver slot by removing some material.

Here's a side-by-side photo of the original handguard and the new handguard. This photo shows the rear of the handguards. The original handguard has a rectangular protrusion that fits into a slot on the receiver. The protrusion on the new handguard is wider and the top of it is shaped kind of like saw teeth.

KR-016B_1.jpg



Here's a Photoshopped picture showing how I want to re-shape the protrusion on the new handguard to match the original one.

KR-016B_2.jpg


My plan is to use a Dremel tool. I think I can use a thin cutting blade to remove the material then bevel the edges with a sanding tool if necessary. However, I'm not experienced in this sort of thing and I'll only get one try so I'm curious if anyone has any tips or suggestions? I want to do this as safely as possible since the new handguard was a little pricey.

Thank you for any advice you may offer!

[kcstott]

bench vice and a good file would do just fine.

[pklin1297]

what kcstott said... The "original" you posted looks like it was filed to begin with...

[ar15barrels]

I use a foredom tool.

[ThatFishGuy]

A rotary tool would work great if you can control it. But plastic is almost too easy to remove with one. If you don't use a rotary too regularly, I was just use files. Even those can remove polymer too quickly if you're not careful. Just go nice and slow, and check your work often . Good luck

[hermosabeach]

use caution with heat on plastic.....

some of the dremel tools will generate enough heat to start melting polymers and it becomes a gooey mess...

you need to try it at first to see how it works...

I think a hack saw might be a better starting tool.

clamp the hand guard in a vice and cut once on the horizontal access to the correct depth, or a bit shallow- repeat on the vertical axis.

use a flat file to finish.

[ar15barrels]

use caution with heat on plastic.....

some of the dremel tools will generate enough heat to start melting polymers and it becomes a gooey mess...

That's why I use a rotary file in a Foredom tool at much lower rpm than a dremel runs at...

[Hiknefer]

Thanks for the great advice! I didn't think about the heat issue. I'm glad I asked before cutting!

[Twystd1]

Do you access to a mill or a drill press with a X / Y table and a vise?

If not. Go slow with a dremel, file, sand paper, razor knife or whatever you have. Then hit it with a heat gun and re-texture to match.

If ya get stuck. Pm me. I have all of those tools. Cost = coffee

-T

[spfabrication]

"Beat to Fit, File to Finish and, Paint to Match has always been my mantra...

Just be sure and sneak up on it.

[kurac]

I would hit that with a sharp chisel, should be a couple minute 5-10 minute job, make sure to wear some thick leather gloves in case you slip.

[SVT-40]

What Kvar shipped you was the light for the stamped receiver guns. What you need is the light for the milled receiver...

Before you start chopping call them and pitch a BitC#... It was their mistake. They should be able to send the correct light...

Their description clearly states the light you ordered is for the milled receiver type. What they sent you was the light for the stamped receiver...

[Hiknefer]

Do you access to a mill or a drill press with a X / Y table and a vise?

If not. Go slow with a dremel, file, sand paper, razor knife or whatever you have. Then hit it with a heat gun and re-texture to match.

If ya get stuck. Pm me. I have all of those tools. Cost = coffee

-T

I think I'll try using a hacksaw blade because it can lie flat against the base to make a level cut. There's enough extra material to try a couple test cuts. If that doesn't work, then I'll accept your generous offer.

I'll give it a try next weekend when I have plenty of free time.

Thanks for your advice.

[Hiknefer]

What Kvar shipped you was the light for the stamped receiver guns. What you need is the light for the milled receiver...

Before you start chopping call them and pitch a BitC#... It was their mistake. They should be able to send the correct light...

Their description clearly states the light you ordered is for the milled receiver type. What they sent you was the light for the stamped receiver...

I contacted K-Var and they were very helpful. They told me they stopped making the flashlight for the milled receiver. They just forgot to change the product description on their website, so this is my only option.

[Awesomesauce]

let us know how it goes, what went right and what did not (for future refence of course).
Good Luck!