Question

[Art_Framed]

Hi guys, a simple question for you. What is the advantages of a pneumatic under pinner over a foot operated unit. Is it the clamping and speed of the nail delivery ?

[IFGL]

all of the above, but I find the biggest advantage is you don't have to lift your leg up, this just helps keep everything still.
Also on harder woods the pneumatic machines have less problems pushing in the nail, I wouldn't go back to a manual machine, contrary to what people might suggest you can still tell if a pin has been pushed in or stacked.

The only advantages with manual machines are you do not need power or a compressor and they are generally cheaper to buy and ultimately run.

[Art_Framed]

Thanks for the reply. We have an Alpha1 very nailer and over time I have noticed that when the nail is pushed into the frame there is a movement upward in the frame. This is only slight but it seems to indicate that the clamp pressure could be a bit stronger. It seems this is controlled by a spring. So another question is can this spring pressure be increased and had anyone done this or experienced the same issue, cheers.

[IFGL]

That particular underpinner needs the clamp head quite close to the moulding no more that about 10 mm any more than that and you will experience a loss of pressure.

also underneath the pinner, directly below the two rods that the clamp head is attached to, there are 2 bolt's, if I remember rightly these are a alen head, they can come loose, sometimes they can shear, if they are loose tighten them and your problem should go away, if they are sheared take it to your local back street car garage they will quite easily remove the broken bolts and replace them, ask them to locktight them in to prevent further problems, this should be a very cheap and quick repair.

[Graysalchemy]

I found that when I moved over to a Cassese that the joint was far superior, however it does show up the limitations of a morso cut, resulting in me buying a cassese saw.

[StevenG]

I have a CS88 manual and can confirm that on hard woods it can be a nightmare - actually I won't touch them these days, never seemed to get a good join (nothing I was happy with anyway)

Oh, if only I had some money

[Art_Framed]

Will check the bolts in question. I have had a good look under there in the past and never noticed anything out of the ordinary but could have missed them. Thanks again.

[Kwik Picture Framing]

pneumatic underpinner is alot faster than manual underpinner

[prospero]

And they make a nice hissing noise like the doors on the Starship Enterprise.

[Chris_h]

I have a double headed Taurus 292D which I got secondhand from ebay for £250 and it has been fantastic. With the double head its so quick to use and I have never had any problems joining anything or stacking wedges.

[IFGL]

@ Prospero, after reading that I will now have a smile on my face every time I hear someone use the underpinner.

[Not your average framer]

I have noticed that when the nail is pushed into the frame there is a movement upward in the frame.

I suspect that many other manual underpinners can experience the same problems if the wood is something hard such as oak. I have a CS-88 and as someone has already said, the top clamp on my CS-88 also moves at times when joining really hard oak mouldings.

I also have an old Euro pneumatic underpinner, which needs a few replacement parts and problems fixing, but the difference when joining hard wood gives quite a considerable advantage over the CS-88.

[prospero]

The CS88 has a quite soft (polyurethane?) top clamp. There is a harder plastic one that is better for hard woods. I've stacked three 10mm into ash on a CS88 and it does it well. My Euro would struggle to do this.

Oak varies in density more than ash and any pinner will struggle with the very dense bits.

[IFGL]

defiantly right there prospero, I have had pins just fold up rather than push into very hard oak, you do find certain suppliers are more consistent than others at delivering framing grade oak, from certain places I have known up to a 3rd be unusable with normal pinning and the same profile from supplier b almost 100% is good, oddly supplier b is also cheaper.

[prospero]

Most oak moulding from framing suppliers is not too hard. I did once get a local timber yard to mill me up some stuff and that was hard as iron. Even had to cut it on the Morso using half-slices. I didn't even try pinning that. Drilled and screwed. Made a good firescreen.

Oak that needs more than 10mm worth of wedges I would sooner clamp and nail. Fortunately, I have a 'Framemaster' clamp which I bought in a sale yonks past. It's rather like an underpinner, but just the lateral clamp which is opened by a foot-operated cable mechanism. Align the joint and let the pedal go and the clamp grabs it. Then you pull a lever on the side to cinch it up really tight. Easier than a mitre vice as you have your hands free for fine jiggling.
Comes in handy now and then.

If you do a lot of biggish oak mouldings, a Hoffman router system is the weapon of choice.

[ChrisG]

Some of the suppliers that offer a chop service will also route the mitres and supply the inserts for hard woods for a price of course but it should result in good joins.

Haven't used this service myself I tend to glue and clamp hardwood frames and then underpin the next day with a pneumatic underpinner plus hardwood wedges.