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V-Nailer Questions?


PFG, Picture Framing God
I have finally embraced my underpinner. Figuratively of course, not literally, that would just be weird.....

This thing has made me apprehensive, not quite sure why. I just haven't been comfortable using it on real frames for real orders. Getting the mitre sander has helped give me more accurate corners and has made it easier to use the underpinner. I have to say I have been using it exclusively the past two weeks and between that and the mitre sander it has been a joy to build frames. It has more than cut my time in half.

A couple of questions.......

1. I'm not quite sure when to change the sizes of the v-nails. If the frame slopes and has varying heights do you literally use different sizes for each frame, or just stack them? Stacking seems easier.

2. I pretty much have been using the ones in the dark blue package for everything, hard and soft wood. In fact, it occurred to me that I hadn't been considering that fact at all. Is this bad? Seems to me that I invested in way too many sizes and types. It also seems to me that most woods seem to fall into the "hard" category anyway.

3. Speaking of hard wood......my compressor goes to 135 PSI but goes all the way down to 100 PSI before kicking back on. From what I am seeing hardwood needs at least 110 PSI. I thought my brother had adjusted the compressor to fill back up at 110 but it doesn't seem to be doing that. If I can't get this thing to rest at 110PSI isn't there some sort of device/tubing you can put on your compressor to increase the PSI by forcing the air through a smaller tube? I seem to recall hearing or reading something about that. The compressor is new and I didn't completely understand how the PSI thing worked until after I bought it. So, I need to find a way to make this work with the one I have.

I guess that is all the questions for now. Hope they weren't too dopey. There has been a real learning curve for me building frames here. I started out cutting and joining 18 years ago but soon turned to chops and then worked in an environment which had no access to any cutting or joining equipment. I've upgraded the saw, gotten the underpinner and mitre sander and am adding a new vise, so I should be all set when I work these bugs out.

Thanks for any info......
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Art On Canvas

CGF II, Certified Grumble Framer Level 2
Hi Kathy:

You'll grow to really love your new underpinner once you become proficient.

I am constantly changing to different size vnails, depending upon the thickness of the moulding that is to be joined. Usually every frame is different so I am always swithching nail size depths.

I have soft, medium and hard vnails in all three sizes, but mostly I seem use the mediums. Sometimes I will get nicer, tighter corners by using a hard (or soft) nail depending on how hard or soft that I feel (literally) the moulding ia that I'm joining.

I never use two different size vnails in the same frame. I stack instead.

Sometimes I do switch to a different profile felt pad, in the top hold down clamp, as I vnail each corner of a tricky frame profile.

Cliff Wilson

SGF, Supreme Grumble Framer
There was a post (HH?) not to long ago about hard v. soft wood and the nails you need. The key is you DO need to use the right nails!

One is sharp and tapered and one is blunt. If you use a softwood v-nail in a hardwood it will turn/bend with the grain of the wood. I forget the by-product of using a hardwood v-nail in softwood, but I know it was not good.

Most of the profiles I have are softwoods. The difference isn't hard versus soft, it has to do with the kind of tree it came from and the subsequent grain. Trees with needles give soft wood, trees with leaves give hard.

For most of my Oak moulding (seems to be the biggest culprit) I use about 95 PSI and it seems to work fine.

I also use different sizes based on the spot in the profile and change them as i am assembling a corner.

Found the thread --- It was Frank Larson on the following thread



[ 12-18-2003, 06:09 PM: Message edited by: Cliff Wilson ]

Alan Sturgess

CGF II, Certified Grumble Framer Level 2
There is a big difference in what pressure is required depending on what brand of underpinner you have. Please explain what make and model of underpinner you have so you get better feedback.

Generally speaking the AMP Mitre Mite underpinners use much lower pressure than do Cassese and most of the rest of the underpinners out there.


Mike Labbe

Member, Former moderator team volunteer
my compressor goes to 135 PSI but goes all the way down to 100 PSI before kicking back on. From what I am seeing hardwood needs at least 110 PSI. I thought my brother had adjusted the compressor to fill back up at 110 but it doesn't seem to be doing that. If I can't get this thing to rest at 110PSI isn't there some sort of device/tubing you can put on your compressor to increase the PSI by forcing the air through a smaller tube?
Most underpinners and CMCs will have a pressure regulator, which you can adjust to a fixed pressure. (example: a constant 90 PSI, if the compressor cycles between 100-135)

I don't know of anything that will increase the pressure of a compressor, other than adjusting the pressure limit sensor/switch. It's possible to adjust the on and off set limits, so the unit will kick in at a slightly higher pressure. (ex: 110 instead of 100). There should be an adjustment knob or screw under the safety cover, and adjustment instructions in the operation manual. Just be careful not to increase the maximum pressure beyond the safe capability of the unit.

Our compressor comes on at 80 and goes off at 110. The Wizard and Pistorius Vnailer are both regulated at the lower end of this spectrum, and we've never had an issue with vnails and hard wood. The CMC doesn't seem to mind either. We cut some test mats today that had over 750 corners each, and although the compressor cycled a few times, there were no errors. I'm not sure what the regulator is set to for the Wizard, because it doesn't have a guage.


[ 12-18-2003, 09:13 PM: Message edited by: Mike-L@GTP ]


PFG, Picture Framing God
Okay, well maybe I shouldn't say I have "embraced" the underpinner. let's change it to "I have shook hands" with my underpinner. Maybe my problem is the wrong nails.

Sorry I didn't give the specifics earlier. I have a used Cassese 810. I'm sure it is operator error because it appears to be working fine. My compressor has 125 PSI max and I guess it rests to 90 PSI. Whatever my brother did increased it to rest at 100 PSI. The underpinner says it needs 7 bars which means nothing to me. My previous LJ rep is the one who told me it wasn't resting at 7 bars and it would give me trouble.

All this is learned by trial and error and unfortunately the manual does not elaborate on a lot of this. I am getting inconsistent results. Sometimes I will shoot one in and it is fine and I'll do another right after and it doesn't go in all the way. My LJ rep ordered me a wooden jig thing that helps on the angled profiles. I seem to have the most trouble on the third corner, it seems to be it's most vulnerable then anyway.

So from what you guys are saying I need to experiment more with the nails and types of wood. I gather that I should eventually be able to feel the corners tightening up if I am using the right nails....honestly all the corners I have built appear to be snug, no gaps, even the ones where the nail doesn't go flush, the corners appear to be snug. So, I hope the ones I have done up to this point will be okay.

Practice makes perfect............

[ 12-19-2003, 03:37 AM: Message edited by: Emibub ]


SGF, Supreme Grumble Framer
14.50326 PSI = 1bar………7 bar = 101.52282 PSI

This is another example of Imperial and Metric measurements.

Kathy….I would expect that your pressure settings are quite adequate for your underpinner…..for an underpinner pressure is not an exact science……..and unless you have a calibrated pressure gauge……it is a case of a little trial and error……….don’t lose too much sleep on this.....

Experiment with stacking the V-Nails before you go buying to wide a range of sizes…..I only use 7mm and 10mm V-Nails.

I have both Hardwood and Softwood V-Nails…….I cannot recall the last time I used the Hardwood V-Nails……the Softwood V-Nails work for all the mouldings I use nowadays…….in fact I’m not sure if Hardwood in the true sense of what Hardwood V-Nails were designed for are commonly available from moulding suppliers nowadays…….lack of worldwide supply for Hardwood…….last I heard was that Hardwood V-Nails generally only have applications in the Hardwood window manufacturing business.



[ 12-19-2003, 04:21 AM: Message edited by: Dermot ]

Cliff Wilson

SGF, Supreme Grumble Framer
Kathy, Depending on the profile, when a v-nail is just shy of going in, you can turn the moulding over on a soft surface (even foam board on a solid table is ok) and knock the little sucker in with a tack hammer. Obviously this will be a problem with soem of the gesso'd mouldings, but seems to work ok with most of the oaks.

Dermot, Almost every time I've used a softwood v-nail on an oak profile by mistake, it's come out the side! :( This seems to be a particluar problem on the taller mouldings with a 12 or 15mm nail. I can't imagine stacking would be a better solution?

Bill Henry-

SPFG, Supreme Picture Framing God
I've always been reluctant to "stack" V-nails. I have the terrible fear that the second nail instead of forcing the first nail up will slide up beside it and either separate the corner or split the wood.

For very deep mouldings, after it is glued, I let it dwell in the vise for at least 20 minutes before removing it. It may not be strictly necessary, but it makes me feel more secure.

Rick Granick

SPFG, Supreme Picture Framing God
I only use 7mm and 10mm vnails. To help decide which nails, how many, and where they should go on a profile, I made a small gauge out of a scrap of matboard. One end is the exact height of two stacked 10 mm nails, with a mark half way, at the height of one. The other end is the same, but for the 7 mm nails. By holding this little thing up to the mitered end of a moulding, I can tell which nail is appropriate, how many to use, and where to insert them along the width of the profile. On a reverse shape, for instance, it tells me not to locate the outer nail in a spot that is so low that the nail would protrude from the top.
I find that I don't need to adjust the pressure very often, except for turning it down for very soft woods. The trickiest element is the hold-down clamping. I have various sizes and shapes of pads made of everything from foamcore to various dense foams and rubber, to help disperse the clamp's pressure. I just use what seems best for the profile at hand. I also have several various clamp pads that attach to the clamp shaft by magnet (it's a VN2+1).
This combination of measures allows me do do just about anything with the v-nailer.

:cool: Rick

Jim Miller

SPFG, Supreme Picture Framing God

The V-nailer can be one of the best time-saving and profit-generating tools in the shop -- not to mention that it makes better corner joints. If you're not comfortable experimenting with the tool, and wonder what you're missing, get help.

Most of the trade shows have a class or two that includes some v-nailer coaching, and you can always use a demonstrator on the trade show floor. The representatives there know what to do.

You can probably corner one of your sales reps who has framing experience, and get decent advice that way. Or, if necessary, find a framer out of your area who has a machine like yours, and pay him/her to show you their methods.


MGF, Master Grumble Framer
I got a whole batch of hardwood wedges at the start of the week as I was running out of wedges.I didn`t order these and although they join softer woods alright I,ll be swapping them for regular wedges asap.I don`t know why but they just feel different when you join the frame.


When I was first learning on the underpinner about 9 years ago, I would cut my moulding, and then cut two small pieces and test the nails in the particular moulding. After a while I got to know exactly what size nails to use for the different hardnesses of the moulding and profiles so that I wouldn't have to cut test pieces.
It almost gets to be second nature. You can hold a piece of moulding, and tell by its weight, and how the moulding felt when you cut it, whether it needs short , medium, or long staples. Or if you need to router the frame.

K. Allen


PFG, Picture Framing God
Good advice everybody! Thanks for all suggestions and opinions. Jim Miller's comments just confirms why I have been so wary of "embracing" it. I agree that I can't just learn it from reading a manual. There is a learning curve. I have done lots of experimenting and now that I am using it on the real stuff I have to say at least I haven't damaged anything. If I were getting gaps or loose joins I wouldn't continue to use it. So for the time being I will continue to use it on the simple profiles and will use other means on the more sensitive ones.

I have had two different reps offer to show me how to use it but both have quit before I have taken them up on it. A possible plot to keep me from learning the skill? Probably not.....If I attend the Vegas show my first mission will be teaming up with any knowledgeable people and monopolizing their time as much as possible until I am V-Nailer Queen.

At least I know my fears aren't unfounded. I am not too proud to admit I have been framing for 18 years and don't know how to use an underpinner. There has to be a 12 step program somewhere....My name is Kathy and I don't know how to use my underpinner.......

I'll keep experimenting in the mean time.
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