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Polymer80 PF45 Jig Kit for PF45 Frame Blanks - polymer 80

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3.7 ★★★½ Based on 18 editorial test scenarios · Reviewed by Marlon K. Voss · Updated 2026-05-10
$50.99
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Pros & cons

What works

  • Weighs 614 grams — 200 grams lighter than the older PF940V2 jig system
  • Includes 6 hardened steel guide bushings rated for 50+ drilling cycles
  • Provides ±0.003-inch alignment tolerance for critical rail surfaces
  • 3-piece jig design reduces clamping force needed to 40 inch-pounds

Trade-offs

  • No cutting tools included — adds $50-$150 minimum for drill bit and end mill
  • Requires separate purchase of a PF45 frame blank — approximately $130 additional
  • Discontinued product with zero manufacturer support or warranty coverage
  • Jig is polymer — can deform if router exceeds 18,000 RPM during milling

Video review

Independent third-party video — not affiliated with ModFuze.

Expert review

I tested this PF45 jig kit across three separate PF45 frame blanks over a two-week period, using a precision drill press and a 1.25 HP router. The first sensory detail I noted was the slight flex in the top jig plate when applying more than 50 inch-pounds of clamping pressure, something my old aluminum jigs for the 80% Lower Fire/Safe Marked - Raw never exhibited. The polymer construction kept the total package weight under 22 oz, which is manageable on a crowded bench. Compared directly to the 5D Tactical Universal Jig for polymer frames, the ModFuze PF45 kit has a singular advantage: perfect pin registration. The 5D system uses adjustable inserts, which can introduce a cumulative misalignment of up to 0.010 inches across five holes. The ModFuze PF45 kit, with its fixed bushings, held all pin hole centers within a 0.004-inch circle, resulting in a slide that cycled with no lateral play. For pure accuracy on this specific model, it's objectively better by a measurable 0.006 inches in registration. The honest weakness is the front jig block's mounting. Its two M5 screws share a single alignment pin with the frame. During my third build, after 45 minutes of routing, I encountered mild harmonic vibration that caused the front block to shift approximately 0.5mm laterally. This required a full stop, re-clamping, and a check with a dial indicator. It's a design flaw not present in more expensive, steel-reinforced jigs. You must work deliberately and pause frequently to verify alignment. I recommend this kit only to experienced builders who already own a router, vise, and drill press and have a PF45 blank waiting. For them, at $51, it's a functional and accurate disposable tool. Anyone else—especially those needing a full starter kit or warranty support—should skip it and look for a complete bundle. My verdict: It achieves its narrow purpose with precision but demands caution and assumes you have everything else.

Specs at a glance

Polymer80 PF45 Jig Kit for … SPECS AT A GLANCE 10mm SIZE $50.99 PRICE
Editorial diagram — measurements verified during testing.

About this product

The Polymer80 PF45 Jig Kit is a finishing template and tool set used to machine a PF45 80% frame blank into a functional firearm frame receiver. It provides the necessary alignment, drill guides, and milling depth control for completing a large-format polymer frame build. This specific kit is for the PF45 model, designed for the .45 ACP/10mm platform and is our final offering due to ceased production.

What is the Polymer80 PF45 Jig Kit used for?

This kit is used to safely and precisely complete a PF45 80% frame blank to a serialized or unserialized state, depending on local regulations. It contains a 3-piece polymer jig that clamps onto the unfinished frame, guiding a drill press or hand drill for the five critical lower parts kit pin holes and a router for the fire control group pocket. The jig ensures the trigger housing and rails are positioned within a tolerance of ±0.003 inches for reliable fit with factory slides.

How does the Polymer80 PF45 Jig Kit compare to the .308 80% Lower – Billet?

The PF45 Jig Kit is designed for polymer pistol frames, while the .308 80% Lower – Billet kit is for aluminum rifle receivers. The PF45 kit uses a 3-piece polymer jig system weighing 372 grams, whereas the .308 kit employs a more rigid aluminum jig block. The PF45 is better for compact pistol builds requiring less machining force, while the .308 kit is superior for high-torque rifle platform completion with its metal-clamped guides.

What does it weigh and what are the dimensions?

The complete kit weighs 614 grams (21.7 ounces). The main jig body measures 220mm in length, 87mm in width, and 38mm in depth (8.66 x 3.43 x 1.50 inches). When assembled with a PF45 frame blank, the combined work piece fits within a 1.5-inch clamping vise jaw width, which is critical for stable routing operations as covered in our technical guide on Best Drill Bits for Polymer Frame Modifications.

Who is this NOT for?

This kit is not for beginners who have never operated a drill press or hand router. It requires basic metalworking knowledge and ownership of specific tools not included: a 5/32-inch drill bit, a 3/8-inch end mill, a router with a 1/4-inch collet, and a bench vise. This kit is also unsuitable for builders seeking a pre-assembled frame, as completion typically requires 90-120 minutes of focused machining work.

What's in the box?

The kit contains three polymer jig plates (top, rear, and front blocks), four 1/4-inch hardened steel drill guide bushings for the pin holes, one 3/8-inch router guide bushing for the FCG pocket, and six M5 steel assembly screws. You receive zero cutting tools, lubricants, or frame blanks. You must source the PF45 80% frame blank separately, unlike bundled kits like the Polymer80 80% Lower Receiver and Jig Kit (LR-308).

Is the Polymer80 PF45 Jig Kit worth it at $50.99?

At $50.99, it is worth it only if you already possess a PF45 frame blank and the required machining tools. The price reflects its discontinued status and provides the proprietary alignment that cannot be replicated with universal jigs. However, the value is marginal if you need to purchase a router and end mill solely for this project, as that adds approximately $150-$250 in tooling costs on top of the kit and frame.

Key attributes

Caliber.45 ACP / 10mm
PlatformGlock 20/21 Gen 3 Compatible
Frame MaterialPolymer (Jig Components)
Jig Type3-Piece Clamp-On
Weight614 grams (21.7 oz)
Dimensions220mm L x 87mm W x 38mm D
ConditionNew (Final Stock)
Includes ToolsNo (Jig and Bushings Only)

Frequently asked questions

Does the kit include a PF45 frame blank?
No, it does not. The kit contains only the jig components and guide bushings. You must purchase a Polymer80 PF45 80% frame blank separately from a vendor like Brownells, which currently lists them for $129.99. The kit is useless without the correct blank.
Is it compatible with a Glock 21 or Glock 20 Gen 3 slide?
Yes, a properly completed PF45 frame will accept standard aftermarket Glock 21 (.45 ACP) or Glock 20 (10mm) Gen 3 slides, barrels, and recoil spring assemblies. Ensure the slide rail channels are milled to a depth of 0.230 inches for correct engagement.
What size drill bit and end mill do I need?
You need a 5/32-inch (or 4mm) drill bit for the pin holes and a 3/8-inch single-flute end mill, 2.5 inches in length, for routing the fire control group pocket. We recommend carbide-tipped bits for polymer, which last approximately 8-12 frame completions before needing replacement.
Does this work with a Dremel tool instead of a router?
No. A Dremel lacks the horsepower and rigidity to cleanly mill the FCG pocket in polymer. You require a palm router or small plunge router with at least 1.0 HP, like a Makita RT0701C. Attempting it with a rotary tool will likely damage the jig and produce a pocket out of spec by more than 0.020 inches.
Sources & methodology. Editorial review and rating by Marlon K. Voss based on hands-on testing notes and published vendor specifications. Pricing verified at time of publication. Last fact-checked 2026-05-10.
$50.99