Tuning Need Help with FX Impact X Broken/Bad Part Problem

[Griswald]

Hope someone can help. I went to install the new Huma dual port transfer port and the modified pellet probe on my Impact MkII. Installation of the new transfer port was a textbook install - no problem.

However, when I went to loosed the 1.5 socket head screw on the pellet probe... it stripped - the hex hole in the head was already stripped but I made it worse. I was using a brand new set of Bondhus Allen wrenches and put the short side in the small bolt, held it down & straight in to make sure to avoid a problem. Ouch, it was tight and when I kept slowly trying to turn it I felt that awful ‘skip, skip’ that you get when the head is stripped out. It’s still functional but I need to get the stock probe out and put in a new Allen bolt. Can anyone help with ideas for solving this problem.

Thanks!!!

 

[8thman]

The same thing happened to me two weeks after I received it. But in my situation the probe screw stripped out about 3mm out, so now I couldn’t close the action or open. And with the action between open and close because of the stripped out probe screw the gun would not fit into the case that it came with. Then to save time and messing with shipping it to fx I took my gun to the gun smith and two days and $90.00 bucks later he had to drill out the factory screw and retap and replace with a little larger screw. I guess that’s lucky that I gunsmith is only three miles away. Best of luck 

 

[2L8]

Griswald, I struggled with the 1.5mm in my MKII as well, but had success in getting it out without stripping it. Heat the 1.5mm grub area and try a star bit of similar size to break loose the adhesive. After removal I discovered FX used a type of Black Loctite. After clean up and installing the new probe I put just a touch of Blue Loctite on it.

Patrick

 

[8thman]

Just to be clear I know that fx would have taken care of me and they have in the past. It was a matter of time and finding a good box the drive to the post office plus I was more mad at myself for using a slightly worn Allen key. I have never had a problem with fx at any time, and with several different models of guns that they manufacture! Again good luck 

 

[Impact701]

I did the exact same thing ! 

This is how I solved the problem !

It was easy to install !

It works flawless !

 

[Healthservices]

So basically you can perform the steps above to remove the block.



Put the block in a a soft jaw vice. Aluminum or brass.

With a good Allen wrench installed apply counter clockwise presure to the grub scew while applying heat to the assembly, you should not have to crank on the grub screw with a ton of force, as soon as there is enough heat to melt the locktite the screw should start turning easily.

If the screw is damaged to the extent that it is mostly rounded you can try using a torx bit and use light presure, but not hard enough to have it jump or strip while applying heat. It may take a little time to heat up enough to loosen. Just like removing the old power port. Not a lot of pressure needed once the locktite is melted. The locktite will almost act like a lube when melted.

And if that doesn't work you will have to drill it out, and retap but if it is that bad you may as well put an order for a new block and grub screw

Use a cheap propane torch like a bernzomatic

 

[stoti]

Just an added bit of information for you...Once you get the grub screw out, there is a new method of holding the bolt probe in place. Stephen at Kraford Lypt just came out with a new system to keep this from ever happening again. The new part surrounds the bold probe to keep the little grub screw from stripping again, by eliminating it. Take it or leave it, just wanted to share.

Stoti

https://krafordandlypt.com/collections/fx-impact/products/ultra-grip-probe-holder

 

[Hobbyman2007]

I still can’t believe that this tiny setscrew hasn’t been replaced by the FX team yet. I’ve gone oversized with mine right of the bat and haven’t had a problem with it. I had to drill mine out using a reverse drill bit bought from snap on tools. 

 

[Guest]

 

[Griswald]

Thanks to everyone for your replies.

I figured that it must be something like some nasty Loctite or Rocksett. Honestly, though, I hadn’t considered that because of the many instructional videos I’ve seen on YouTube, I’ve never seen anyone heating it up or having any trouble. I think I’ll take the top strap and side plate off so that I can the the block with the screw out and then heat it up. As some of you have said, I should be able to use a Torx bit of a similar size or, maybe, a small Easy Out. Considering the problems I’m hearing of I may just go ahead and drill & tap a new hole for a larger Allen screw to eliminate the problem. But, I really like the Krayford & Lyft solution too. I’ve got a shop full of tools so having the right equipment won’t be an issue. I just wanted to get some other opinions before I did something that couldn’t be undone.

I was going through this exercise because I wanted to install the Rowe modified dual port setup with the low side hole along with the Huma modified probe. After trying that, I want to install the adjustable pin probe that comes with the FX slug power kit to see which combination of parts gives the best results. I plan to shoot mostly slugs (probably FX Hybrids or Nielsens) so I want to be able to push the slugs well over 900 fps out of my compact barrel. I want to be able to dispatch coyotes from my property from 75 yards +/- and I think this should be possible. Has anyone else with a Compact already gone through this exercise?

Thanks again for all of your comments!

 

[Guest]

I work with grub screws all the time. They always strip, and usually from over tightening in the first place. Unfortunately a lot of people over crank them in most applications. 

 

[elh0102]

I have two criticisms about the assembly of most air rifles. First, they consistently over-tighten most screws, and secondly, the use of thread locking compounds. With few exceptions, most fasteners on air rifles can be modestly hand tightened, and need no locking compound. In those few applications where some sort of locking compound may be needed, the screw does not need to be tightened with much torque, that's why the compound is used! If a reasonable, semi-permanent compound is used, the screw can usually be freed with a well fitting screw driver. Worst case, some heat might be needed. Sometimes a torx driver can be tapped into a stripped head to gain purchase to turn it, but a stripped thread remover is worth having around. If those tactics fail, you probably have to drill it out. With a proper size drill bit, this can often be done without drilling away the threads. 

 

[jking]

And if you get into the threads just drill it out to the next proper size for the next size up in metric grub screws and tap it. That's what I did to mine proactively but you'll have to enlarge the hole in the pellet probe as well, all three of them in my case. 

jking

 

[Griswald]

Too right jking! They had this grub screw in so ridiculously tight and with probably some version of Loctite that is non-removable without heat (since I had to use a lot of heat). it was tighter than Dick’s hatband!

Because of the rather large problem I had with getting the probe block grub screw out, I thought I’d do a write up about my experience that might help other Impact owners in the future. My major comment is that I think it’s very poor on the part of FX to use such a setup - a probe block with a very small grub screw that they put in far too tight to begin with. It is a problematic part that is bound to fail for a significant number of owners. I would have expected much better engineering from FX considering that we’re all paying around $2,000 +/- for these air rifles. That it’s a known problem and that FX hasn’t offered owners a replacement part that has been re-engineered so as to eliminate this problem is, IMHO, not a good way to do business and is most disappointing. Parts such and the Kraford & Lypt Ultra Grip Probe Holder and the NSA Adjustable Pin Probe are a testament to how prevalent and how well known this problem is. That said, the overall machining of the Impact is excellent and I’m sure I’ll enjoy my Impact as soon as I get it properly sorted.

Keep in mind that this is by no means the only way this might be done. It’s simply what I tried and what finally worked for me. Use this procedure with caution and remember to be very careful with a torch and NOT to pick up hot parts without insulated gloves, pliers, etc. Use at your own risk.

1st - I took my Impact Compact mostly apart because I am doing some other mods anyway. Remember to keep all of the screws in the top plate and carefully set it down so that they stay in place in the top plate. There are several different sizes of screws and they have to go in the appropriate holes.

2nd - I removed the complete mechanism with the probe block and probe attached.

3rd - I removed the probe block with the factory pellet probe attached. The probe block is attached to the mechanism with 1 screw and with a small pin that sits int the rear probe block hole and keeps the block properly oriented. [Don’t lose the pin! It’s quite small and easy to lose].

4th - I put my heat shield pad down on my bench, fired up my torch and heated & heated & heated & heated some more, trying to turn the grub screw with an Allen bit several times along the way without success. Remember ... all of these parts are VERY HOT at this point. DO NOT handle them without using pliers or proper gloves.

5th - With the grub screw area still very hot, I next used the closest, slightly oversized, Torx bit that I have, more or less drove it in a little by hand and slowly tried to turn the grub screw out ... it still WOULDN’T BUDGE!

6th - After trying step 5 several times with no success, I used a drill/bit to enlarge the Allen recess in the head of the grub screw. A word of caution ... don’t go crazy with this.

7th - I heated the pin block grub screw area again, quickly put the pellet probe block in my vise, put my smallest Easy Out in a small Vise Grip plier, put the Vise Grip plier with the Easy Out in the enlarged hole in the head of the grub screw & very slowly, with downward pressure on the Vise Grips, I began slowly turning the Vise Grip plier counter clockwise. This finally allowed me to get the !@#$ grub screw out.

Again, I feel that this is a ridiculous amount of work to have to do in order to replace a pellet probe. While I’m certainly going to complain to FX I’m also going to fix this problem to my satisfaction. I’ll either drill a larger hole and tap for a larger grub screw or, and more likely, I’ll buy the Kraford and Lypt Ultra Grip Probe Holder that stoti was kind enough to tell me about. It looks like a beefier setup with a larger grub screw that will eliminate this problem altogether & it allows you to use either a modified pellet probe (such as the Huma version) or an adjustable pin probe (such as the one that comes in the Impact Slug Power Kit).

Thanks to everyone for you comments and suggestions!

 

[heavy-impact]

I didn't read the whole thread but when you strip an allen head just find or grind a flat blade screwdriver or bit to tap into the stripped allen head. Once tapped in kinda solid you'll be able to turn out the damaged grub screw. Keep plenty of downward pressure on it while turning.

 

[bzizzi373]

Drill the grub screw out using a left hand drill bit available from McMaster Carr, left hand means you drill CCW instead of CW, most of the time bit will grab the screw and turn it right out of threaded hole. I have a whole set of left hand drill bits for this exact purpose. If screw doesn't come out just keep drilling until it's gone and no longer holding probe in place.

 

[Griswald]

Hello Heavy Impact - Yup, that would normally work for me too; however, the opening in the head of the grub screw was rounded out enough that a blade screwdriver couldn’t get any purchase. So, the Easy Outs - what I guess many people call bolt extractors these days. I’m old enough to have grown up in a time when these were known as Easy Outs, sort or like every copier is a Xerox machine.

 

[Griswald]

Hi bzizzi373 - Same thing I’m calling Easy Outs. Some people call them bolt extractors. And, left hand drill bits as you say. I have a set too, usually keep 2 sets because it’s so easy to break the small bits. Thanks

 

[bigHUN]

...they consistently over-tighten most screws, and secondly, the use of thread locking compounds.

...you probably have to drill it out. ...

This

just heat it up and you need to brake a bond with high moment of and not loosening it slowly...

if you really need to drill it out, use the screw extractor...

if you damaged the thread (but shall not happen if you just use a common sense), re-tap it for the same size -> thread inserts, these comes in titanium as well

and don't use thread locker again, a bee's wax or just anything thicker "rubber like bonding material = hotmelt" will hold that screw...

 

[Griswald]

Some good ideas bigHUN; however, 

1. The Allen cavity in the head was too rounded to be able to loosen it quickly with either an Allen key, a Torx bit, etc., even when heated up.

2. Most screw extractors will not work in this situation with a small cavity that is already well rounded, which is why I used a left hand drill bit and followed with a small Easy Out,

3. Of course I didn’t damage the threads hence, my comment to others not to go crazy when doing this,

4. I will not retap at the same size as this is overwhelmingly thought to be the source of such problems and there have even been blowouts because of this as can be found with a search of this forum.

5. I don’t have local access to any Helicoils or other small threaded inserts, which is why I will retap for 4mm to get me by until I get my Kraford & Lypt piece. This looks to me to be a more substantial and better engineered piece, and,

6. Thread locker is probably not needed in this case; however, I don’t see a problem with using a judicious (think small) amount of blue Loctite to prevent possible backing out as has happened to others, particularly when moving up to 4mm as I’m doing.

Thanks!