Underpinner

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MHodson
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Joined: Wed 29 Jul, 2020 10:10 am
Location: Manchester
Organisation: Halo Picture Framing
Interests: framing

Underpinner

Post by MHodson » Fri 09 Apr, 2021 10:30 pm

Hi everyone,
Can someone please give me some advice. What are the advantages to an electronic under pinner? Will they stop the gapping at the join?
Many thanks
Michelle Hodson
Halo Picture Framing
242 Elliott Street
Tyldesley
Manchester
M29 8DS

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prospero
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Joined: Tue 05 Jun, 2007 4:16 pm
Location: Lincolnshire

Re: Underpinner

Post by prospero » Sat 10 Apr, 2021 2:20 am

Some machines have lots of bells'n'whistles. They are aimed at high-volume work and will not necessarily give better
joins than a manual. They are waaaaay more expensive and there is a lot more to go wrong. They also need a reasonably
high volume compressor for continuous use.

If you are not familiar with underpinners I would say get a manual one and upgrade later if need be. :wink:
Watch Out. There's A Humphrey About

Abacus
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Location: Halifax, West Yorkshire
Organisation: Abacus Picture Framing and Gallery
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Re: Underpinner

Post by Abacus » Sat 10 Apr, 2021 8:06 am

The gaps are not usually caused by the underpinner (unless your outside pin is too near the outside edge) it is caused by either your cutter, your cutting technique or warped moulding.

The cassese cs1 is a manual underpinner which I’ve heard good things about. They cost around £1200

We use a cassese cs2 which is a pneumatic version of the CS1, we are happy with our joints. They cost around £1400 but need a compressor.

I’d like a cassese cs20 which is similar to ours but has clamps to help with alignment these cost around £2500 and I can’t justify the extra money

The Mach4 is an electronic underpinner which has a memory of profiles, you press the pedal once and it puts in all the v nails you’ve programmed it to do. I’d love one of these, but at £9,000 it’s not in my budget!

I think any of these would be fine, if you’re getting gaps, it’s probably not your underpinner as I said above.

If you could let us know where your gaps are and the kit you have, we could have a go at diagnosing the problem.

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Gesso&Bole
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Re: Underpinner

Post by Gesso&Bole » Sat 10 Apr, 2021 8:24 am

There are a lot of different underpinners out there.

Some will do the job faster, some will clamp better, have more power than others etc, but I suspect that if you are getting gaps, like Abacus says, it might not be anything to do with your underpinner, but to do with your cutting technique.

In which case you could spend £3000 on a new underpinner to get faster gappy joints!
Here for the love of picture framing - happy to share any knowledge I have

Not your average framer
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Re: Underpinner

Post by Not your average framer » Sat 10 Apr, 2021 2:47 pm

Gapping at the join is a problem which comes up a fair bit from time to time. It can be due to some sort of problem with the alignment of the fences on your Morso, the Morso blades might need sharpning, the Morso blade might have been incorrectly ground, or the fences on you underpinner might need abit of a tweek. Rushing out to buy a new underpinner is very unlikely to solve anything.

So It's a methodical sequence of slowly going through checking what''s happening. Start first with the Morso. Maybe you need to check if your blades are nice an sharp, before doing anything else. If they have not been sharpened for a very long time, changing the fence setting can appear to put things right, but dull blades don't always cut the same on different mouldings, so you need to be sure about this.

Assuming that the blades were previously correctly sharpen try cutting thin pieces of paper, such as normal thickness photocopying paper on the Morso just like you use the Morso when cutting mouldings. Check that there is a nice clean cut along the length of both blades. This only tell you that the blades are sharp and cutting properly and it's not telling you if the morso's fences, or the adjustment of the bottom blades relative to the main Morso blades are correctly set. That all gets checked later!

Next it's time to check the alignment of the bottom blades relative to the bottom blades. These need to be adjusted one at a time. Press the foot pedal fully down and lossen the allen key headed screws on the bottom blade of one side and push the blade over to come in contact and parallel alignment with the main blade on that side. This only require gentle pressure (nothing more) slowly go from each of the outer screws, back and forth tighten the screws a bit at a time and also tighten the middle screw as well. Check by raising and lowering the foot pedal to check that the is freedom of movement and no binding as the blades move up and down. Even slight binding is too much and will not do the blades much good!. Then repeat this for the blade on the other side..

Using a known straight straight edge, Check the alignment of the right hand side fence on the Morso, with the long measurement rule on the right hand side measuring entension. It is necesary the this fence is in line with the rule on the long rule of the measurement extension and when this has been set, the right hand Morso fence should be locked into this position. Now it's time to adjust the left hand side Morso fence and this is something that we all find difficult at first. An easy starting position is too align this using your straight edge And cut two piece of reasonable wide flat wood (3" wide is quite good). Line these up together as if you are preparing to join them and measure the angle between the outside of the corner with a try square and usually this will be less than 90 degrees, However the adjustment to the angle of the left hand fence is going to be something like about a quarter of the magnitude of the visible error.

I like to join the two pieces together on the underpinner, while holding the two pieces of wood together such that I have closed any gap at the mitre joint. Now it's time to determine the magnitude of the error between the outside faces of the two joined pieces of wood and the try square. Not everyone does this like this, but I stack small pieces of photocopying paper together and count how many thicknesses of photocopying paper is needed to fill the gap between the end of the piece of wood and the try square. Now count the pieces of photocopying paper the correct angle adjustment will be somewhere near to a quarter of the number of the sheets that have been counted. At this stage you are ready to make a trial adjustment of the left hand side Morso fence. Take a nice strain piece of wood, or moulding and position the moulding in position against both fences.

The left hand side fence needs to be move back towards you and the appropriate number of sheets of photocopying paper need to be positioned at the same distance for the centre of the gap between the fences to correspond to the distance from the mitre join on the two peices of wood previously cut and joined and between the piece of wood and the fence. Don't forget that this is now a quarter as many sheets of photocopying paper as were previosly counted. Now cut four pieces of wood to join together as a test frame. For any gap that it still left your will need to and an extra sheet of photocopy paper to the number of pieces used to calibrate the fence position, then after reseting the fence position and recutting the frame pieces and rejoining the four pieces on the under pinner.

If the gap needs reducing instead of adding an extra sheet of photocopying paper, just remove one. Not everyone does it quite like this, but it is quite easy to explain. As you get more accustomed to adjusting the left hand fence, you probably will not need to bother with all the silly little pieces of photocopying paper. This is just a straight forward way of doing it, when you have not been doing it long enough to eye ball it and guess how much to tweek it by. I hope that this is helpful.
Mark Lacey

“Life is short. Art long. Opportunity is fleeting. Experience treacherous. Judgement difficult.”
― Geoffrey Chaucer

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