mitres

[jaymar]

I want to cut some segments accurately. The segments will be fairly small and I will only be cutting them occasionally. What is the best way, a compound mitre saw other means? B&Q have mitre saw and so do Axminster(fairly cheap). Any advice is welcome.

 

[Philly]

Jay
What tools do you already have?
Philly

 

[Steve Maskery]

Jaymar
It depends on how accurate and how often. It also depends on how precise the angles need to be. If you want 45 deg accurately it's one thing. If you want 39.7 deg accurately, it's another.

I have a Nobex Champion saw for sale at the mo, advertised in the back of this month's GW. It is a frame saw, and does common angles with indents, and common compound angles too, by preset tilted positions of the workpiece. It's a decent level of accuracy, but the surfaces will probaly need a lick with a plane on a shooting board. I've managed quite nicely with this for several years unti I bought a SCMS last year. My Nobex now gathers dust. PM me if you are intrerested.

If you want a machined finish you need to look at a powered mitre saw, and these vary in price from sub-100 to a few hundred. Needless to say, the more expensive ones are better, but that doesn't mean that the cheap ones won't do what you want. It depends on your requirements.

In this month's GW I have a general article on mitres, with some cutting and clamping ideas, and in last month's I had an article about using a sine bar. With this you can get precision not just to degrees but to minutes, using an ordinary mitre gauge on a table saw.

HTH

 

[RogerS]

How small is 'fairly small' Jaymar? If very small then I would worry about my fingers and using an SCMS.

 

[jaymar]

The pieces i want to cut are not miniscule, About 15 mm square would be the smallest section x perhaps 40mm. I have a table saw, scms and radial arm saw but have not been able to cut a decent mitre on any of them. I am mostly into turning and want to make some segmented bowls which do require accuracy so as nt to leave gaps when glued together.

 

[Slim]

You should be able to cut them on the tools you have. Sounds like you need to spend a bit of time adjusting your tools to be more accurate rather than investing in a new one.

 

[RogerS]

At that size my preference would be a decent mitre box and a Japanese fine tooth saw.

 

[Fecn]

Jaymar,

I had trouble getting my mitres bang-on with my SCMS... until I worked out a really simple trick.

Take a sheet of paper (I use fairly thick A3 paper for this) and fold it to a 45d angle... Sit it up against the fence on the SCMS.. and then (with he power off) change the angle on the saw until the teeth on the blade meet up with the edge of the paper all the way along. Slide the saw back and forth and ensure that it's accurate all the way along. Rotate the blade a bit by hand (because they're not necessarily totally flat) and then try the same thing again. If the teeth still brush against the edge of the paper nicely, you're ready to cut.

Here's a pic... although I'm not sure it will make things clearer.

I've given up using the scale marked on the saw itself... It's about 0.3 degrees out. One of these days, I'm going to make myself a 45degree wedge of MDF to speed up my saw-setup

Hope that helps...

Fecn

 

[Shultzy]

For the sizes of material you are using I would go with Steve Maskery frame saw as it give a finer cut. To get an accurate angle use either a shooting board with a angled stop or the same, attached to a disc sander.

 

[Anonymous]

Am I right in assuming your wanting to build up a round form from small brick like segment's or are we talking about barrel like staves that go the full length of the form in one continous piece? If your doing barrel staves, use a planer with a acurate fence set to the angle you want, or just do it by hand keep a sliding bevel set to your angle to test.

I have never done any segmented turnings but I have made drum shell's from laminated segments which were curved in profile like a barrel, but also with a mitre angle (which I obtained by drawing rather than mathematickal calculation so am not sure what the angle was in fact I dont need to know it!!). In my case the segments werent a part of the final finish as such as it was painted, but if your using various coulours etc and you DO need the segment positions as part of the finished design, I think you will find it helps greatly to draw the plan view of the staves onto painted plywood or something firm and stable and lay them up onto the drawing (rod). It is far easier to spot any spiralling in or out, or other acumulated error, and maintain the correct diameter and so avoid one stave having to be adjusted and end up being too small, or worse, end up with a gap :shock: , especially if finished diameter is critical which I think it is on some segmented turned work? With this method it would be much easier to build up layers of segments of different wood's etc for the brick layed effect. I always prefer to rely on the rod than rely on the saw to do the acuracy part of the work, as fecn said the guages are unreliable; in fact I wouldnt fancy cutting such little pieces with a power saw. When I did the drum shell's I was honestly astounded when the last segment just fit in like a key stone none of the segments needed micro butchery to get good fitting glue lines. I just used inner tubes to clamp it up like giant rubber band's.

If the rod's right the job will come out right :lol:

PS to answer your original question, I'd just cut the pieces by hand. Someone sold me an ulmia little mitre saw something like that would be ideal, and with the pieces being little, adjust if necessary with the disco sander.