Underpinner problems….

  • Thread starter Thread starter Justan2
  • Start date Start date
Create a Post
J

Justan2

Guest
I’ve never used and underpinner before this weekend.

I just got a new to me, but well used ITW AMP VN 2+1 out of the shipping box, watched some videos, read the manual twice and promptly encountered some problems when I started using it.

Here is the problem: No matter how tightly I press the vertical clamp or “hold down rod” as it is called in the manual against the moulding, when the v nail is driven, the force of the v-nail causes the moulding to lift and push apart with a result of a poor join.

The underpinner came with 2 padded pressure plates that fit between the hold down rod and the moulding. One pressure plate is circular shape and the other is V shaped. No difference in the results with either pressure plate. I have the hold down rod tightly secured and it does not slip, except for the first couple of times when i didn't tighten it enough.

The pneumatic hold down rod does compress against the wood when the foot pedal is activated in position 1, but it does not appear to apply sufficient force against the nail driver mechanism.

I have a hunch but don’t know if this suggests that one or both of the vertical cylinders are in need of maintenance.

I’ve tried using the underpinner with and without the “frontal clamp” and the separation problem is worse when using the frontal clamp.

The moulding i'm using for testing is fairly thin hardwood, about 1.5 inches wide, and I’m using a 7mm v-nail that came from a box which states the v-nail is for medium and hard woods. I’ve tried using from 40 lbs. to 80 lbs. of pressure as indicated on the gage on the underpinner and get about the same results no matter what pressure is being applied.

The underpinner has an air leak somewhere. I have a small air pump connected to it and if I leave the underpinner unused, the air pump will turn on every 5 minutes or so.

Any suggestions on how to troubleshoot or if there is a service company in the Seattle area?
 
It sounds like the top, or hold-down clamp, may be set too high. It should be no more than an inch above the molding. When this is the case, the nail pushes up the wood. I set it even lower - about the thickness of a finger.

Your pressure sounds OK, but a warning - when you're joining softwoods, lower the pressure a lot, or the clamp will leave a crease mark in the molding.

Re the front clamp - many times I don't bother with it.

Here's another tip - can you find a retired framer close by, who will come in for a fee and save you a lot of learning time on the machine? He/she may be able to tune it, and may even have spare v-nails to add to the cause. You never know.
 
What I do is raise the hold-down rod and lightly lock it, then press the pedal half way to lower the hold-down bar. While it is down, I lower the hold-down rod until the pad rests on the moulding, and again lightly lock it in that position. Then I let the pedal up, and then lower the hold-down rod about 1/2" and tightly lock it. This ensures that the top clamp rod is not only just holding the moulding, but applying pressure to it as well. You will learn the proper pad thickness and shape choices for various mouldings through experimentation.
 
Oops, Rick, you beat me to posting. I don't type very fast....o_O
It sounds like you do the same thing I do.

When I used the VN2+1, I would set the pressure foot height by loosening the pressure foot bolt lever, hit the peddle so the pressure foot will come down and just rest on the top of the moulding.
Tighten the pressure foot bolt lever and take your foot off of the peddle and let it rise.
Then loosen the pressure foot bolt lever and lower the pressure foot about 1/2" and tighten it in place.
This should provide the proper downward pressure in most cases to join.

If you still have issues, there is a new Grumbler, Carver (Keenan Carver) who is the service tech for Fletcher which now owns ITW AMP.
You might contact him and speak to him about the problem.
860-409-1574
 
Just sounds like you are not allowing the two stage process to work. Partial pressure on the pedal engages the clamp and holds the corner firmly. Once this is engaged additional pressure pushes the v-nail into the wood. If you allow it to happen all at once the moulding will jump up before the clamp is fully engaged. Also on the 2+1 the clamp does not move with the head so you need to be sure the clamp is on the most firm position and be sure the v-nails are not beyond the positive clamping hold.
 
Hey Justan,
I'm a repair tech for Fletcher-Terry and the AMP VN2+1 is one of our machines. It sounds to me like you have blow-by in one or both cylinders. This is caused by the O-rings inside them wearing over time and is a common problem with used machines. If you get a chance today see if the air leak is coming from one of the blue mufflers on the rectangular control valve under the machine. There should be 2-3 rectangular control valves attached to each other and they are the only parts on the machine with the mufflers on them. To see if one is leaking unscrew the muffler and put your finger over the hole you will hear an audible change if that's where the leak is coming from. If you have a leak there than either the control valve is bad or the seals are bad. If its not coming from there than there are a few other troubleshooting methods I can guide you through so that you can diagnose the problem and order the parts needed today. My contact information is in my signature feel free to get ahold of me any time.
 
Thanks to all for the very helpful tips and suggestions above.

I spoke with Keenan Carver a few times, or maybe more than that, and between his generous knowledge, the suggestions above, and a lot of laying on of my hands to tighten and test things, I have the underpinner functional. It still has more air leaks than a parachute made of chain mail, but with the use of a good stethoscope I was able to find and eliminate a lot of noisy leaks. I plan to change out some gaskets and disassemble the major components to make sure everything is tight, but not for a couple of weeks.

Today I was able to produce my first workable test results. That took many tries, and my compressor may develop asthma before I can rebuild the underpinner.

I also contacted the seller (from Ebay) to relay to him that the underpinner was a whisker short of being in “Good Condition” as was advertised and he naturally denies there were any flaws. I bought it several months ago but never got around to testing until last weekend, so there may be little recourse other than leaving an honest review and turning to my CC vendor, who has been very good at this kind of thing in the past.

The amazingly good news is that not only does AMP fully support this ~ 16 year old underpinner(!), but their support reps are very generous with their time. Best of all is that for not much more than a good dinner and wine for two I can replace or rebuild anything it may need.
 
Hey, Justan.
What can happen often with these machines is that they may be in great shape cosmetically, but if they haven't been used in a while, the seals and o-rings dry out and harden and you get leaks.
I have rebuilt cylinders before and it's pretty easy actually.
Just disassemble, clean, lube and replace the seals and/or o-rings and you're good to go.

We use a Cassese at work but I have a VN2 at home that I own personally.
My VN2 is about 15 years old and works perfectly, but I rebuilt both upper cylinders and replaced one of the 3 multi-function valves in the past.
Put a couple of drops of recommended oil in the air inlet once a week.

As far as the stethoscope, I always just used a length of rubber hose held to my ear, but it's all good and will find a leak.

AMP ITW has always been very good with customer service and tech support.
Fletcher has taken over and they seem to be carrying on the good service.
 
Last edited:
^ Agreed with all the above. Everything develops problems over time due to inactivity and/or regular use. In this particular instance, it is a combination of the aging related details you mentioned along with virtually every air line fitting being not even finger tight when I got it.

I’m planning to replace the major issues I found and see if they solve other problems. For instance, I can hear air leaking in the vertical cylinders and also in the control valves. They are directly connected by air lines. The thought is that by fixing the cylinders, which I learned is a common location for leaks on these older underpinners, this may stop the air noise in the control valves. Or not. It may take a couple or more passes to get everything worked out, but I’m confident it will get there.

The best part for me is that the underpinner is the last major detail of about the last 4 weekends I’ve invested in putting together a shop to make frames and I am very happy that it is all coming together. I have a long show that starts next week which kicks off my show season for the year, and have to make 40 frames for that show.
 
Progress.

I’ve made about 30 of the 40 frames over the last few days and have come into some production related issues.

No matter how carefully I try, I can’t get the underpinner to make a tight join. Due to that I’ve been using some miter clamps to glue the moulding with wood glue and then let the glue cure for about 15 minutes before joining with the underpinner. This produces great results but the time involvement is a pita. I ordered more clamps. What else can I do to speed the process? Is hot gluing by way of a glue gun a useful alternative or does it create problems?

On the plus side, gluing provides better results than i've seen in most frames because it makes it possible to precisely align the the moulding at the front.

My works are all non-standard in sizes. Due to this every pair of moulding pieces has to be measured, marked, and cut. What is recommended for marking the moulding? I’ve been using a china marker (a.k.a. grease pen) but it produces a black line on dark moulding and that is both hard to see and is not very precise because the marker is so wide. What do you use to mark the moulding for cutting? Do you use the Phaedra system or put a nick in the moulding, which will be sawed off or???

Thanks!
 
Justan2 said:
My works are all non-standard in sizes. Due to this every pair of moulding pieces has to be measured, marked, and cut. What is recommended for marking the moulding? I’ve been using a china marker (a.k.a. grease pen) but it produces a black line on dark moulding and that is both hard to see and is not very precise because the marker is so wide. What do you use to mark the moulding for cutting? Do you use the Phaedra system or put a nick in the moulding, which will be sawed off or???
Thanks!
Click to expand...

You aren't going to find many here that mark and cut mouldings. Almost all of us have saws with outfeed tables with calibrated scales and stop gauges so no measuring or marking is needed.

Here is a entry level single saw Clearmount system.

Frame_Moulding_Cutting_Joining_Equipment_ufe1217h_Large_Laurie_MO.jpg


The scale and stop gauge mean no measuring or marking are necessary.

You didn't mention what you are presently using for this. If you aren't using such a system or better, perhaps an investment in a saw system would be appropriate given the number of frames you are making.
 
Thanks for the feedback. Prior to reading this I had only read of the Phaedra measuring system. Does the Clearmont system have any +es or –es in comparison?

I don’t have anything i'd call a "system" in place but rather have a kludge of stuff that notably includes 2 dewalt compound miter saws, some T squares and several dedicated work benches. I’m definitely looking for a better/quicker way to cut and join moulding.

Any comments about the use of a hot glue gun or something else to speed the glue-before-joining-with-the-underpinner process?
 
Use Corner Weld glue for a faster extremely strong glue joint. It is excellent for gluing first and nailing last since it has some elasticity to it.

If you want to get some better advice I would recommend that you post photos of your saw set up along with the moulding being used. Slight variations in angles and overall length of cut moulding can make a huge difference in the quality of the miter joints.
 
I don't know what your budget is but here is something that you might be able to work with that's cheap. Its 80 smakeroos. I found it when I did a search for "framing miter saw scale"

Since your present system is a "kludge" you might be able to add this to it. It only works up to 36" but there are ways around that.

http://www.frameworxz.com/picture-framing-saw-fence

Nothing is going to beat a good double miter saw but this might be a good temporary measure for your present setup.
 
Use Corner Weld glue for a faster extremely strong glue joint. It is excellent for gluing first and nailing last since it has some elasticity to it.
Click to expand...

Thank you for the suggestion! Can you tell me the approximate drying time? I’d have been done probably a day ago if it didn’t take 17 minutes for the glue to dry enough to be stable (at about 62 degrees) before joining.

Slight variations in angles and overall length of cut moulding can make a huge difference in the quality of the miter joints.
Click to expand...

Yes they do!! I am fairly OCD when it comes to doing something right and this project reminds me in ways of when I put in hardwood floors at my home, in that wood has its predictable, uh, eccentricities, which have to be resolved in one way or another if you want good results and tight joins. Of course, with a hardwood floor, you can use the nail gun to resolve minor warps. With frame moulding, it takes considerably more finesse.

Prior to starting the project and periodically during it I checked the saws and the miter corners with a variety of tools to verify that all the angles are correct. Naturally, the biggest variable is the wood itself. I also found along the way that using my disk sander was the best way to get rid of any remaining variables. That is, after I got that squared properly…. This morning I found a cool angle finder with a digital display that I’m going to get as it makes the job quicker and more precise.

I have the last 2 pieces to assemble this morning and will spend much of the day mating the works with the frames, and then putting the new framed works into my trailer so I can load in for the next show on Thursday. After that is a 11 day long marathon where i will long for the peaceful time while making frames!
 
I don't know what your budget is but here is something that you might be able to work with that's cheap. Its 80 smakeroos. I found it when I did a search for "framing miter saw scale"
Click to expand...

Thank you! I also found a Phaedra measuring grid at the following location that I might get. http://www.pictureframingequipment.com/moulding.htm They want $85 for that, and iirc it is 60”. Skylinepictures.com has some used measuring systems made by both Clearmont and Phaedra in the ~ $400 price range.

Setting up the shop included putting a heater in the space (and a lot of other sutff) and due to that my budget is a little drained at the moment but after the next show I will get one of the measuring systems along with a much bigger air compressor/tank combination(!), and also begin to remove the air leaks in my underpinner, heh. I do like the idea of the rigid stops that the full measuring systems include.
 
Corner Weld is pretty dry in 5-10 minutes. I join with it wet and start fitting frames immediately without any problems but on very large and complicated frames I will join one corner in the v-nailer and wait 5 minutes before joining the next.
 
^That’s a lot better than the 17 minutes the current goo takes to setup enough to be moved.
 
Carver said:
Hey Justan,
I'm a repair tech for Fletcher-Terry and the AMP VN2+1 is one of our machines. It sounds to me like you have blow-by in one or both cylinders. This is caused by the O-rings inside them wearing over time and is a common problem with used machines. If you get a chance today see if the air leak is coming from one of the blue mufflers on the rectangular control valve under the machine. There should be 2-3 rectangular control valves attached to each other and they are the only parts on the machine with the mufflers on them. To see if one is leaking unscrew the muffler and put your finger over the hole you will hear an audible change if that's where the leak is coming from. If you have a leak there than either the control valve is bad or the seals are bad. If its not coming from there than there are a few other troubleshooting methods I can guide you through so that you can diagnose the problem and order the parts needed today. My contact information is in my signature feel free to get ahold of me any time.
Click to expand...

Hi I have a Alfamacchine U300 underpiner I believe its the valve problem after I press the pedal I can hear air leaking from inside the machine and it takes almost 20-30 sec until I can shoot again again do yo have any suggestion ?
 
Can you find where the leak is coming from? Is this a new problem, or has it become worse over time? Is it possible that a hose was pulled loose in a recent move? Do you regularly lubricate the machine's internal parts by injecting pneumatic tool oil into the air supply input port? Sometimes a lack of lubrication can result in leaks that may be resolved by lubricating.

I suggest you contact Grumble member Mark Thornton at Underpinner Spares. He is most knowledgeable about these machines and may be best able to help you troubleshoot.
 
Create a Post
Back
Top