Thread: Fundamentals: cutting things square and true to templates

Looks like you need a band saw or jig saw with the way they are now glued down on the one board . There are some cheap small Band saws at Aldi's I'm told that would be OK on 12 mm ply.
What I think you need to know is which are the most important angles and sides of the shapes and work from that . Knowing where they fitting in the finished piece. And that determines how you cut each piece out . If only two sides of a triangular brace need to be dead on, then cut out the piece over size first , with two square edges true, lay or stick the pattern to that and proceed on the not so important angles.

With what you now have you can cut them out and shoot the straight angles with a plane on a shooting board to get them right . That's if your machinery , Your Saws wont do it .

Rob

Being the simple bloke that I am I would have glued the parts that require straight edges to the edge of the ply, first ensuring that the sheet was cut square. That way you have one reference edge.

If you have no reference edge, and nothing prexisting square, then I would stick with the sled on the tablesaw, but hotmelt glue the piece to be cut onto the sled, in such a way that the line to be cut is lined up with the blade. Afterwards, gently separate the hotmelt.

Another option is to put your sled aside, put the fence back on, and rip a piece of ply to use as a makeshift sled. Provided you don’t move the fence, then every time you push the makeshift sled through the blade it will run exactly along the previously cut edge. Hotmelt glue your workpieces onto the makeshift sled, such that the edge you want to cut is lined up with the previously cut edge on the sled. Push it through the saw. Gently prise the hotmelt apart.

Double sided tape works too, just make sure it’s of the sort that won’t allow movement when passing through the saw.

Awesome advice guys! Exactly what I needed.
I’ll sleep soundly now lol

I love the hot melt glue and I know now that getting a reference edge is the first step.
Gluing the template on square is not necessarily going to be too hard since I can check the drawings and paper edges for square.

I’ll do another set of templates in the morning and reconsider the whole shebang overnight!

Can’t spring for a bandsaw now SWMBO is at the Very Limit!
I could have cut straighter with the scroll but I wasn’t thinking far enough ahead.

I have a plane and decent vice but I don’t know of the technique.

My saws are good enough to cut straight and i proved it making my sled and router fence but gee, that took a longtime and I double checked everything ten times.

Plus I was working with more straightforward pieces.
Now I have some guidance I will have at it again.
Best,
Will


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And I’ve just learned about shooting boards from the master.
https://youtu.be/ZKYli4sMGwM

Originally Posted by notch

I have a table saw, sled (cuts square) and compound mitre saw with a good blade but not super accurate quality.

Hi Will

looking at the templates you have attached to the ply, most if not all are probably best cut without gluing the template down.

I'm seeing lots of straight lines and uniform curves which can be set out with an architect's or draftsman's circle template or a pair of compasses.

Your existing table saw and sled can cut accurate 90 degree corners and for most of the frame components, what will be important is that the pieces match rather than they are exactly the same as on the template.

ALSO
keep an eye on the grain orientation. The finished clock will look off if the grain direction is not uniform piece to piece.
In particular, the grain on the back frame should run up and down, not diagonally across the piece.

Ian, yes... So true.

The Baltic Birch has such a beautiful presentation and this is an important concern for me of course!

Here I was trying to conserve material and not really thinking grain from a cutting or performance perspective as it is so stable - but completely forgot to consider the importance of the most obvious feature of the clock “in perpetuity”, other than whether it’s working or not!

Thank you for mentioning this and yes, I will do some work today on my CD ply with my tools and what I’ve learned to see if I can make a rough frame.

Will



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Guys, everything that I’ve read here made my day today a very significant one.

I think today I finally “got somewhere” in the sense that I was able to dial in my method and refine my tool setups and end up with a full set of frame parts cut perfectly square and matching exactly.

I tried to incorporate all the advice I was given in this thread and it kind of all came together.

I started the day setting out to prove my saw cuts square and whilst it became immediately apparent that if I took enough care the fence and saw pair were reliable there was a problem with my sled and I had to fix some slop in the action and then readjust the fence according to the 5 cut method.

I took my time and used a piece as large as I could cut comfortably and dialed it in.



The square never lies and I took that as my main project - can I get properly cut square pieces repeatable from different scrap stock?

Well...

After trimming to this degree with the 5 cut system:



And screwing down my sled fence. I began to find myself cutting pieces I’d measured out and getting exacting results.



Clearly I know that at my level and with the Triton/underslung saw and beginner made sled when I say “exacting” i realise that this is not going to be to the level most of you use the term with. But if I was getting things clean and true to my set squares I was happy!



Marking out and cutting pairs led to very satisfactory results.







In the end I have a complete frame set which next needs cutting out and half laps.





So I’m a very happy camper - I had a really fantastic Sunday arvo in my shop.

I want to thank everyone who gave me inspiration with this fundamental step in such a positive and encouraging way. I felt like I had a host of options, most I’d never thought of and it allowed me to start seeing things from a new perspective. Hence my methodical efforts to practice what I’d been taught!

Have a great night guys!
Will


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To finalise this project today I revisited the sled and how it fits to the Triton.

Part of the issue is the way that the mitre guides interact with the rails.

Firstly there is always going to be some inherent inaccuracy in the pressed steel and aluminium fittings and because they are slotted and don’t go right through the table I was limited in the length I could use.

Consequently I was using the fence at its widest point to reference the sled square - but there was still some movement that I was not happy with. I couldn’t get it to slide smoothly and without binding and still have no possible angular movement!

Overnight this went round and round in my head and today I screwed outside rails to the sled to act as additional, longer guides.

This way I got rid of all the slop and although it’s a little stiff here and there i is always running straight - so I then did a final calculation using the 5 cut method as presented by William Ng on YouTube.
https://youtu.be/UbG-n--LFgQ

And got things down to a really really fine tolerance.

Probably as good as I’ll get with this gear.

Just for interests sake here is the finished piece and some numbers achieved.





The five cut process took only one calculation as promised by William Ng.

Calculate the difference between A and B widths after cutting a piece 5 times - proceeding to cut each time with the previous cut on the fence.

Then ((A-B)/4)/length of 5th piece is your error (in mm for eg) and you multiply that by the length of the distance between your pivot and adjustment point on the fence, use a feeler gauge and clamped stock to set the adjustment (taking into consideration the +/- to move left or right). Unscrew, move and clamp fence, drill and fix and your done.

Here’s the numbers I got.

First error 1.03mm across 370.5mm, which is 0.275mm across 370.5mm let cut, or 0.000695mm per mm and my pivot length was 573mm so I needed a 0.398mm too far up on left. So I used a 0.4mm feeler gauge on right and then adjusted the fence.

This gave me a new A and B of:

0.05mm across 343.5mm or 0.0125 per cut over 343.5 and this is an error of 0.000036mm/mm or 0.0036%

Time will tell if it’s repeatable but I suspect if I’m careful with the sled and the saw (in particular when swapping it out for the router etc) it should be about as good as I’d get on this gear!




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