choosing underpinner

[red]

Ive done a days training and have been busy reframing my old pictures
on pretty basic tools. but not too bad a job
I have decided on a morso and a keencut ultimat or similar when
I get round to creating space.I only intend to be a hobby framer from home
as ive retired. ive looked at table top underpinners do they do as good a job
as a floor mounted one? whats the pros and cons? any advice most welcome

[Jamesnkr]

Get yourself a pneumatic one. I probably make no more than 200 frames a year, if that. I wouldn't swap my (rather elderly, slightly wheezy) pneumatic one for anything else.

[red]

thanks for that pneumatics are the business I agree, but I don't want
to spend too much and I'm also an old luddite!

[prospero]

I've used a manual pinner for 30 years+ and it's done a lot of frames and still works fine.

Cons for pneumatics....

You need a compressor.

Lots more things to go wrong.

You can't 'feel' the pins going in.


Pros for pneumatics...

They make a nice hiss-kerplunk noise.

[Jamesnkr]

Pneumatic underpinners are tabletop and so take up less space. You only need spend £250 on one second hand; a new floor-mounted manual one could cost you the thick end of £1000.

And Prospero has a right leg as thick as an ancient oak tree's trunk...

[vintage frames]

Yes but ...
Buying a Morso is the most important tool, and well worth any money spent. Get the cut right and you're 90% there.
An underpinner is just a quick way to staple mitres . Are you going to be making lots and lots of frames or just say the odd one or two? I would advise instead buying a good quality frame clamp, good quality PVA and some framing pins when the glue has set.
With a frame clamp you get lots of wiggle room to get the mitres close as the clamp tightens. With the underpinner, and if the cut is slightly out, then once you press the pedal there's no going back!
Perhaps get used to using the morso and then think whether you need the convenience of an underpinner.

[Glimpse]

I use a basic Cassese underpinner that I bought secondhand very cheaply. It's completely bulletproof, very reliable and gives perfect results.

The one thing I learnt - and I imagine this goes for all underpinners - is to learn how different frame shapes react under the pressure of the pinner. Some 'scoops' seem to be perfectly designed so that the head/pad forces the joint apart during pinning!

Obviously, the pinner works best when pushing against a perfectly flat moulding, so I try and add the outermost wedges first, and then use a flat piece of MDF to spread the load when adding the inner wedges.

The odd bad corner will always happen no matter how good your equipment - due to knots or soft spots in the wood - but these can usually be sorted with band-clamps afterwards.

I use the cheap (£5) ones from Screwfix, modified with a bit of felt glued into the corners to protect delicate mouldings.

Another thing to bear in mind is that it helps to have a large, empty surface at the same height as the underpinner to support larger frames and prevent straining the joins you've already made. I made a small workbench that I can move around when needed.

[red]

thanks for advice I will ask santa for a floor mounted manual one!