Everyone is trying to save money these days and that includes me. When you start talking about quality carbide end mills and cobalt drills, the costs rack up fast but there are options for you to save money and I’ll make this short and sweet.
To be clear, these folks did not pay me or even know I was going to do this blog post. I’m not getting a dime from them.
I needed to buy a 3/4″ reduced shank cobalt drill bit. These things are usually around $40-50/ea and I was able to get a nicely made Qualtech from Drills and Cutters for $32.91 out the door. I use this bit for drilling out the top of my AK-12 grips and the glass reinforced polymer shreds HSS bits so discount Silver & Deming bits don’t last. Spending the money for a quality bit made from cobalt makes a ton of sense because it will do hundreds of holes before it needs to be sharpened.
So, Drills and Cutters is a web store that you can buy from and they may have the manufacturer ship direct to you. I have found their pricing and shipping speeds very good.
They sell drill bits, taps & dies, cutters & saws, reamers, end mills, carbide burrs, annual cutters and more.
The second group I want to share with you is EndMillDiscount.com. Carbide is not cheap and “cheap” carbide tooling does not hold up. I go through a fair number of carbide end mills and carbide spotting/centering drills each year. When you need to drill hardened steel, there are situations where you simply need the hardness to cut. So, I needed to order in more 1/4″ bits and started shopping around. With the word “Discount” in the site’s name I was a little nervous but they had *really* good prices and I couldn’t find any negative reviews so I took the plunge.
I ordered 4 of the HTC 4-flute 1/4″ diameter end mills at $7.15/ea and 2 of the SwiftCarb Spotting/Centering drills at $16.98/ea and shipping was only $10.51. Wow, in just a few days the end mills arrived drop shipped from HTC and then the drills arrived drop shipped from SwiftCarb. I was very impressed.
End Mill Discount sells end mills, drills, micro tools, cutters, cobalt tools, carbide burrs and more.
I definitely plan on buying from them again. Visit them at:
I finished my Polymer80 PF940CL build and was pretty happy with the results. This is a really interesting Glock-compatible variant that is unique to Polymer80 that I really like. It’s a G19 lower designed to work with a G17 upper. This is why they call it the “compact long” (CL) model. Basically the handle doesn’t print as much under clothes plus you have the longer barrel and slide with the longer sight radius. It’s a win-win.
Back to the story, I built the PF940CL and it function tested just fine. It shot like a dream other than locking the slide open once in a while. I had a pretty good idea the recoil spring was catching on my purposefully so-so sanded area where I removed the barrel block from in the frame.
I bet you’re wondering – wait – what? He did it in purpose? Yes, I did. I’ve read about guys having this problem and wanted to recreate it for a blog post and also to allow me to demonstrate a new sanding tool kit I’ve assembled to make the work easier and faster.
To avoid this, just be real careful about not leaving an edge. Historically, I would mill out most of the plastic and file the rest down flat using a combination of wood dowels and popsicle sticks to provide a stiff backing for different grits of sand paper. It was tedious but it got the job done and it will work for you as well.
A better way…
Ever since my first Polymer80, I was wondering how I could reach in there with a hand tool and get ridge of the plastic in a more automated fashion but also still have enough control to not make a mess. For example, a die grinder with a burr would scream through the plastic and destroy everything in the blink of an eye,
Dremels / rotary tools give you a ton of sanding options but nothing that would allow you to reach straight back from the nose of the frame and be able to sand the “U” and its curved surfaces.
I kept digging around and hit on the idea of using a 4″ shank mounted in a slow turning hand drill and using sanding rolls. That worked great! I was able to source 80, 120, 180 and 240 grit rolls to allow me to start course and move finer and finer.
So the sanding kit includes the You don’t need it to be so smooth that it looks like it was never sanded – that’s why the sanding kit only goes up to 240 grit.
Start with a lower grit and move up to the 240 grit. The 180 and 240 grit drums will clog up with plastic pretty quick so they are more for finish sanding than removing a lot of material. I use compressed air to blow the plastic out of the drums and you could do that or use a stiff brush to clear the drums as well.
Please let me stress to you that slower is better. If you are using a drill on high speed or chuck these into a die grinder, they will remove material super fast. In my honest opinion, too fast. I have my old Ryobi drill on it’s low first gear speed and just take my time by sanding a bit and checking over and over. I would urge you to do the same – you want to remove all material inside the “U” but no more.
A problem that can happen with a Glock-type of pistol is known as “doubling” wherein the pistol fires one round when the trigger is pulled and a second one when the trigger is released. For those of you all excited about learning how to build a binary trigger for a Polymer80 or Glock pistol, this is not the way to do it. The problem almost always happens when someone starts adding modified components vs. OEM Glock or goes polishing/sanding on parts.
Modifications to the fire control group can lead to unpredictable results because of stacked variation – this means that each little part can vary a little and when you add them all up, you can wind up with way more than the acceptable level at the end. With this in mind, you always want to test functionality before going to the range the first time and when you fire for the first time, load one round. The next time load two and remember to keep the pistol safely pointed downrange at all times.
I bet the pistol has been modified for this to happen
Okay, for a Glock design to double, somebody has altered the geometry of some of the parts through polishing or maybe they swapped parts, went to aftermarket parts, bent something, sanded on something, changed out springs that cause the firing pin lug to jump the sear — bottom line, something was changed. If you went with aftermarket parts, sanded or polished some of the fire control group and are now trying to figure out what happened, I’d recommend you replace whatever you touched with OEM Glock while you figure out next steps.
Today’s story focuses on the role of the connector
Well, Gaston Glock was a firearms genius and designed a unique fire control group (the trigger, firing pin, connector and what have you) that was unique at the time. One could argue a lot of companies have copied his design pretty closely.
Glock wanted both a reliable and safe pistol and the interesting thing was that he had no prior firearms design experience before the original Glock 17. Probably in part due to this, he came at the problem with an original point of view and created his “Safe Action System”.
What we want to focus on today is the connector. The connector is a metal stamping at the rear of the pistol connected to the trigger housing. When the trigger is squeezed, the connector forms a ramp that guides the trigger bar downwards thus releasing the firing pin. When the slide returns, the hook on the connector follows the track in the slide and the connector should move to the side allowing the trigger to reset . When the trigger is released it moves back into position for the next cycle. If the geometry is wrong for whatever reason, it will fail to block the firing pin from returning forward resulting in doubling.
Let’s Watch A Video
To be honest, I feel like every time I watch a video or read something about the Glock design I learn more and sure don’t claim to be a Glock guru. I sure am a very interested user of the design though I prefer Polymer80 frames and their angle to an actual Glock brand pistol.
Watch this excellent animation on how a Glock works and pay attention to what the connector is supposed to do – this is what can go wrong with an aftermarket connector.
My Doubling Story
I took my brand new Polymer80 build G34 pistol to the range for testing and, hopefully some fun. A model 34 is basically a model 17 with a longer barrel and slide. My intent with it was to be a range gun so I tricked out just about everything. I literally think the magazine release spring, trigger block and extractor were the only OEM parts 🙂
When I took the pistol to the range and started test firing it was immediately apparent there was a problem because the pistol fired on the pull and release. It was inconsistent as well sometimes firing just one round and sometimes firing on the pull and the release. I was bumming because I meant to pack parts with me if I had a problem and forgot so it went back in the case while we tested other firearms.
So, what happened?
After I got home and started working on it, I realized I really hadn’t function tested it repeatedly enough. I definitely paid very close attention to what the pistol did when I released the trigger after racking the slide. I could replicate the doubling most of the time just like what happened at the range – it wasn’t doubling consistently during testing either, which is why I missed it.
Function testing going forward
Based on what I learned, here’s what I would recommend for function testing and do it 3-5 times before you go to the range:
Absolutely make sure the pistol is clear / unloaded – both the chamber and the magazine.
Squeeze the trigger just to make sure you are starting with an uncocked pistol.
Rack the slide
Pull the trigger – you should hear a click. DO NOT LET GO OF THE TRIGGER – Keep it pulled back.
Rack the slide again with the trigger pulled
Now listen carefully and watch the slide, when you get go of the trigger do you hear a click as the firing pin incorrectly goes forward? If so, you have a doubling problem.
If you did not hear a click, go ahead and squeeze the trigger as you normally would and you should here the click of the firing pin.
Now repeat steps 3-7 and pay attention when the slide cycles with the trigger being pulled. It should never fire upon release.
I had researched the springs and trigger carefully. What I questioned was the connector and it did turn out to be the Apex brand connector. To address the problem, I replaced it with a standard OEM Glock connector – problem solved. Note, this can happen with other aftermarket connectors as well such as Ghost so I am not singling out Apex. There’s no way a manufacturer can take all the possible combinations/variations into account so I don’t blame them at all – it simply happens and is something you should not be surprised about.
A more thorough video on changing the connector from the folks at Brownells
If I have time in the future, I may contact Apex and see what they recommend I do but for now, I’ll stick with the Glock connector. One of the key takeaways I want you to have is that it is important that you test your builds before you ever rely on them. If it fails, ask yourself – what did I just change and focus your efforts there.
Click here if you want to see other posts about Polymer80 pistols.
I hope this post helps you out.
Polymer80 and Glock Parts Vendors
When you want to customize your Polymer80 or Glock, or you need replacement parts, there are a number of solid vendors you can go to: