Senco Framing Gun Problems

[RTM]

All

I have a Senco SN60 Framing Nailer with a problem or three. I've poked through the archives, and see lots of references to buying a nailer, but nothing on repair.

I bought it used a few years back, got it home, fired a few dozen nails, then put it away for a future project with a friend. He tried to start the project back in February, but the gun only fired a few shots, then quit, leaking air out the top. He had a line on a second gun, so I ordered a rebuild kit right away, got the gun back in July, and finally tore into it this weekend. Found out two o-rings near the top of the gun were just goo. Cleaning this was probably the worst part of the job, besides deciphering what happens next.

To work on it, I pulled off the nail magazine, which made it easier to grab in the vise, but unfortunately all the interlocks fell apart, so spent some time deciphering how those worked. But it is all together now, and works fine, for 2-3 shots.

Then it stops with the driver pin down, so obviously a retract problem. Pulled the top off the gun after it stopped the 3rd time, and found that one of the parts had dislodged, red arrow in the first image. It climbs up maybe 1/8" or less, but that seems to be enough to foul up the airflow. It is a hard plastic part, apparently functioning as a valve with its uphill partner, BF0145.

I have replaced all the o-rings, and the two critical teflon like parts (BF0102 on the top of the part that is moving, and LB5054, top of the next part stack on the right.) It is tight and not leaking after assembly (amazingly), and packs quite the kick when it fires.

I am wondering if the piston, bottom of the left stack, is over traveling its stop position, which seems to be the top slots (not the castellated part) in the cylinder, 2nd piece down in the second stack.

My gun does not quite look like the exploded drawing, as there is an extra bumper which I believe goes below the BB0149 in the center of the second stack, and above the FC0281 in the bottom of the middle stack, and the interlock for the magazine being present has a different spring in it.

It may have been rebuilt once before, as a couple of the square rings are o-rings (LB0809 top of middle stack), and maybe LB0042, which looks square, but isn't called out that way.

Also, do any of you Bay Area, especially Peninsula, guys know a good pneumatic repair guy or shop? I see a couple in the east bay, but not sure its worth the $$ to fix.

Thanks all

 

[RTM]

Anyone? Hate to bump, but hate having a dead duck in the garage.

Thanks

 

[PugetDude]

I had a Senco SN325 Framing gun, it was the biggest POS and most frustrating tool I've ever owned. .
The local Senco dealer rebuilt it once under warranty and gave me two rebuild kits for when the warranty expired., I rebuilt it once- same problem you describe. Finally gave up, threw it in the trash and bought a Paslode framing gun.
Save yourself the aggravation. Dump it before you waste any more time, money or mental energy on it.

Interestingly enough, I really like my Senco finish and pin nailers.

 

[RTM]

Funny, I have a new to me Senco SFN1 from 1989 or so, O rings etc seem fine, but the nails are double feeding. Need to find some new nails to test before it joins its cousin.

Thanks for the opinion.

 

[Bigblockyeti]

I was a factory authorized Senco tech years ago, there should be nothing below BB0149 and the guide body (FC0281), that might be your problem. The older guns really had to be taken care of well, dropping them in a drawer without first oiling them and pulling them out 5 years later expecting them to work perfectly ensured disappointment. Using proper air tool oil is also mandatory, I rebuilt many due to framing apes putting ATF in them assuming it would prevent freezing, it only made for problems. The M1, SN70, SFN1, SFN2, SN325 and SN325+ guns were some of the best ever made, but you had to take care of them or you were going to have problems, sadly this was outside the skill set of many using them.

The most important thing for long life from any air tool is dry air and very few contractors or framers take the time to install a simple water separator for $20 then wonder why they have problems.

 

[PugetDude]

The M1, SN70, SFN1, SFN2, SN325 and SN325+ guns were some of the best ever made, but you had to take care of them or you were going to have problems, sadly this was outside the skill set of many using them.

When reality bites, blame the customer.
Yep, that'll work.
Problem solved.

(You do realize you just called out half your framing guns as unsuitable for the average consumer ??)

 

[Bigblockyeti]

When reality bites, blame the customer.
Yep, that'll work.
Problem solved.

(You do realize you just called out half your framing guns as unsuitable for the average consumer ??)

Sorry son, it's fact.

No doubt, Ferraris aren't for the average consumer either. These are also the same guns used by the guys who framed exclusively while taking home over $150K after expenses. Smart folks take care of the stuff that pays the bills, others blame operator error on the tool.

 

[RTM]

I was a factory authorized Senco tech years ago, there should be nothing below BB0149 and the guide body (FC0281), that might be your problem. The older guns really had to be taken care of well, dropping them in a drawer without first oiling them and pulling them out 5 years later expecting them to work perfectly ensured disappointment. Using proper air tool oil is also mandatory....

Thanks, will take the lower half apart tomorrow, maybe you can tell me where this stray piece goes then, based on wear marks, this seemed the most logical. I am still able to have the tip barely outside the nose at full extension with it there.

I though Senco manual said don’t oil. I was worried about oiling O rings to install them.

Thanks

 

[Bigblockyeti]

Thanks, will take the lower half apart tomorrow, maybe you can tell me where this stray piece goes then, based on wear marks, this seemed the most logical. I am still able to have the tip barely outside the nose at full extension with it there.

I though Senco manual said don’t oil. I was worried about oiling O rings to install them.

Thanks

Post a picture and I'll see if I can recognize it. The tip should protrude only slightly when pushed all the way down, with rated air pressure it will be just over 1/4" and if captured by a high speed camera when shooting, the maximum would be over 3/8". Absolutely lube the o-rings during assembly and oil it during operation. The "oilless" guns I've seen that were never oiled were in pretty rough shape after not very long. Most of this stems from finish carpenters and woodworkers not wanting to risk oil suspended in the exhaust potentially staining what wood they are working with, not so much of a problem rough framing.

 

[toplessHO]

I have had a Senco SFN finish nailer for 25yrs and its been a beast.
Yes I oil good every use and before storage.I still have a big bottle of Senco oil
that I use in all my air tools.

 

[Jeffh40]

My Senco nailers (2" finish nailer and a cabinet stapler) are of the oil-less generation. I've never oiled them yet in 20 years, but they don't get used much anymore. YMMV.

 

[mikegt4]

I have an old Senco SN325+ framing nailer, made right here in Cincinnati. I used it to build my house 30 years ago. A few years ago my son borrowed it to do some work on his house and found that it wouldn't work right. I took it apart and found a broken piece inside, just my luck NLA. My son's new battery powered nail gun (don't remember the brand) can get into tight spaces that the old Senco could not. I still can't bring myself to throw it out, it's almost a member of the family. Senco made great products back in the day.

 

[RTM]

This guy seems to have some parts for your 325

https://www.rebuild-kits.com/?s=Senco+sn325

 

[RTM]

Ok, I just took apart the gun, and took a measurement on the way through.

The tip currently sticks out 0.325" when pushed down manually.

Once I got the lower end apart, I can see the plastic / rubber bumper is starting to erode, probably due to misassembly, or age. It was fine when I put it in.

This is the order I had the pieces in the gun initially, based on the wear (metal marks on the rubber pieces), marks on the metal lining up to the gun.

This is the bottom side of my piston.

I'm wondering if I need to reverse the two green pieces (think they replaced a taller BB0149 with two pieces). Otherwise, I have no idea where the smaller smoother of the two green pieces go.

BB0149 was replaced by BB0224, but its discontinued at certain places.
https://www.amazon.com/dp/B00BBPXKYG/?tag=atomicindus08-20

Thanks all for any guidance. Its currently in pieces on the kitchen counter, in hopes someone has a quick answer, or needs more pictures.

 

[Bigblockyeti]

That looks like an early, 2 piece piston bumper, given their size, they definitely both need to be there. Personally I would replace them both with a newer one for the sake of reliability, the little pieces of green rubber are signs of early failure. It still might last forever at a DIY pace but could fail quickly in the hands of a pro feeding their family with that tool.

 

[RTM]

Cool thanks. Trying to decide if $20 added to the value of this will fix the upstroke knocking out the top pieces or not.

 

[RTM]

Well hell, sounds like PugetDude was right, I should just walk away. It looks like part BF0205 might be too small. I replaced it with one that came in the rebuild kit, and it seems to be the thing that stops the piston from retracting too far.

Seems only one guy sells that part, and lots of places are cloning his ad.

Any thoughts on putting a glob of silicone on top of that to add a few mm of height, or some thing behind it if I can get it back out? It’s a mushroom fit, afraid I will shear it trying to push it back out.

Thanks