Cutting a window using 3.5mm mountboard

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Mrs C
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Cutting a window using 3.5mm mountboard

Post by Mrs C »

hello fellow framers
I hope everyone has stayed safe and well these past two months and managing to weather the storm.
Re. the above subject, I hope someone can help.
I haven’t used extra thick mountboard for some time and from what I can remember, past experiences proved tricky. I have a large vintage poster to frame using a thick window mount and I only have a couple of sheets so no room for mistakes.
I use a Keencut Ultimat Gold. Do I need to change blades and is setting the depth one of trial and error?
Any advice welcome.
Carol
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prospero
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Re: Cutting a window using 3.5mm mountboard

Post by prospero »

I find this a bit of a trial. The thing is to use multiple passes - starting with the blade set at a shallow depth and gradually
extending it. Two passes if you're lucky. Mostly three or more.

Also you need to make compensations in the end stop. (the one nearest to you). I add 2mm when cutting 2.4mm board, so maybe
+3mm. So if the margin is 70mm, the end stop should be set at 67 or less. Best course is to set it by using a piece of scrap the same thickness.
The top stop doesn't need compensation as the extended blade ensures your start point is right.

Trying to do it all in one cut needs excessive force.
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Re: Cutting a window using 3.5mm mountboard

Post by Not your average framer »

I find it very hard to get nice clean results when cutting 3.5mm thick boards, without getting scuff marks on the bevel from the entry, or withdrawal of the blade. I generally aim to cut such boards in four cuts to avoid taking too thick a cut at each time. The final cut is generally made with a brand new blade to that the last cut is a good one. I don't offer customers 3.5mm boards and hope that they won't ask for them either. 2.5mm is trouble enough for me and 3.5mm is a bit thicker than I like to go by choice. 3.5mm boards cut much better on a CMC in my opinion. I'm semi retired and don't work as many hours as I used to, so I can mostly do without all the bother these days..

I sometimes produce double mounts, using two different thickness of board. It used to be quite popular a few years back, but that look is not very popular these days. Perhaps it's just as well! I also used to do a reasonable amount of V grooves as well and that has slowed down quite a bit too! Time goes by and things change and they may well be gone forever. I still like doing deep hand finished bevels to be fitted behind a normal mount, they are not that hard to do, but I can't even remember when I did the last one. I was planning upon retiring before I got to 70, but a lot has happened since then and my plans for the future are a bit up in the air these days.
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Re: Cutting a window using 3.5mm mountboard

Post by Steve N »

To practice, cut a smaller window than the finished one required, if you do it at least 25mm smaller, then you should be okay, then when happy, do it at the finished size
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Mrs C
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Re: Cutting a window using 3.5mm mountboard

Post by Mrs C »

Those are all very useful tips, thanks guys. Glad to hear it’s not just me then! :)
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Re: Cutting a window using 3.5mm mountboard

Post by pepper »

The Ultimat Gold should cut 3.5mm but check the following:

* The cutting head should have minimal (ideally zero) side play or the board will use that loose movement to pull the blade slightly off track and once the blade starts to veer offline it will bend the blade tip so it can continue on its path. Then sometimes, on a large mount, you may find the blade comes back in as the cut progresses, this could be due to your arm/elbow position influencing the attitude of the cutting head as you pull the head towards you.

* Make sure the board is being clamped properly, as has been said before check the surface you have the cutter on is flat and not bent or twisted.

* Blade depth is all important, it should just be cutting into the surface of the slipmat. The longer the blade tip the more flexible it becomes and will obviously bend easier. On a side point here, it is often a mistake to think a thicker blade will prevent the blade bending in this situation, a thicker blade should always be the last resort.

* Lastly, but in most cases has most influence, is blade type. 3.5mm conservation board will certainly need a chisel or single edge blade either the Keencut TECH S 012 or the thicker TECH S 015, make sure they are positioned the right way round in the blade holder (you can only use one tip). If you don't have any drop Keencut an email and they will send you some samples of each to try.

If you are meticulous about all points above you should be OK, by the way you will need to calibrate the stops but this is simple to follow in the manual if you haven't had to do it before.

One last thing, someone mentioned scuff marks on the bevel, if you see this it will most likely be on the end of cut. This is caused by the blade effectively running backwards when exiting the cut. This rubs the cut fibres of the board in the opposite direction to produce the scuff. Try holding the blade down then lift up the long black handle a couple of centimetres to un-clamp the board then retract the blade holder to pull out the blade and rather than the blade running backwards it pushes the board away and the blade twists out without scuffing.

Hope all this is not too unwieldy!
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