Use of sliding compound mitre saw

[CWatters]

Perhaps this is a question for people who frame roofs or do other large scale work...

Say you need to cut lots of 90 degree half lap joints in 6" oak. Is this something you would use a sliding compound mitre saw for or would you use a circular saw?

I've not owned a compound mitre saw and I'm trying to work out how flexible they are. Looking in screwfix it seems many will make the depth of cut required (3") but will they do it in a 6" thick beam? .

Using a circular saw across a beam like this is essentially a free hand cut unless you get into clamping on bits of wood to act as a guide.

 

[Digit]

Trying to push a long piece of timber across a TS to cut a half lap is a pretty dodgy idea. For that the SCMS is likely to be the better option IMO.

Roy.

 

[skipdiver]

You wouldnt get a six inch piece of wood in mine.It will cut about four inch timber at a push so in theory it would do the required depth but the timber wouldn't go under the blade.I would tackle this job with a radial arm saw but not a slider.Your other method sounds better but 3" depth is a lot even for a big circular saw.If you have one capable of doing it,then i would use some kind of jig and do it in stages to the required depth.

 

[Rich]

Once again, this is another question I would like to reply to as I cut a lot of lap joints, but I don't feel happy replying to a man who has no christian name and I don't know where he lives, some will find this pedantic, but to me, it's nice to know who you're talking to.
Regards,
Rich. (from Reading.)

 

[dennis]

Have you got a hand held circular saw as I have sometimes half lapped timber freehand with one.

Dennis

 

[mailee]

I have the large De Walt SCMS the 718 and I dont think that would cut a six inch thick piece. Another problem with a SCMS for cutting half laps is that you will have to space the timber away from the fence otherwise you end up with a concave cut in the lap face. Maybe a router and jig would be the way to go or as has been suggested a hand held circular saw and a guide. HTH.

 

[dennis]

The larger hand held saws will cut just over 3inches and working your way back from the end of the timber to the shoulder you only need a guide if you havent the confidence to follow the shoulder line freehand which I have never found a problem.

Dennis

 

[CWatters]

Once again, this is another question I would like to reply to as I cut a lot of lap joints, but I don't feel happy replying to a man who has no christian name and I don't know where he lives, some will find this pedantic, but to me, it's nice to know who you're talking to.
Regards,
Rich. (from Reading.)

Sorry. I'm Colin Watters and live near Huntingdon in Cambridgeshire. Going to be building a green oak framed shed as soon as I can get planning permission.

 

[CWatters]

Have you got a hand held circular saw as I have sometimes half lapped timber freehand with one.
Dennis

Hi, Yes I have a CS but haven't yet checked if it will cut 3" deep. In the past I've had problems with keeping the cut straight even with a guide...The blade seems to bend too easily when trying to make deep cuts - as if the kerf isn't symetrical - possibly due to rubbish blades?. Was a big problem when trying to cut railway sleepers last year. Ended up cutting them by hand which was quite a lot of work.

I'm expecting to have to buy or hire some tools to do this project and was really trying to work out whats best to go for. There won't be many half lap joints - most will be M&T but the half lap is the deepest.

 

[BradNaylor]

Once again, this is another question I would like to reply to as I cut a lot of lap joints, but I don't feel happy replying to a man who has no christian name and I don't know where he lives, some will find this pedantic, but to me, it's nice to know who you're talking to.
Regards,
Rich. (from Reading.)

Sorry. I'm Colin Watters and live near Huntingdon in Cambridgeshire. Going to be building a green oak framed shed as soon as I can get planning permission.

Don't worry Colin,

You've just encountered the village silly person.

Most people on the forum preserve their anonymity - including the moderators!

 

[CWatters]

The larger hand held saws will cut just over 3inches and working your way back from the end of the timber to the shoulder you only need a guide if you havent the confidence to follow the shoulder line freehand which I have never found a problem.
Dennis

Thanks for the reply. Would you be able to recommend a good make of blades for a CS?

 

[Digit]

You've just encountered the village silly person.

I never said a word!

Roy.

 

[Argee]

... it seems many will make the depth of cut required (3") but will they do it in a 6" thick beam?

I may have got hold of the wrong end of the stick regarding measurements, Colin, but you speak of a 6" beam with a 3" cut, so I imagine that the 6" dimension is the depth of the beam, not the width of it?

If that's so, the depth of cut on the SCMS is irrelevant on its own. What you propose would require that a three inch cut be completed with the blade still three inches above the table, wouldn't it? Plus, the timber would need to be stood off from the fence sufficiently to allow the blade to complete the cut horizontally. As far as I can see, that would require a very large capacity saw, but if one is available it's the repeatable way to do the job.

If, however, the 6" is the width, and 3" is the depth of the beam, no problem with the majority of SCMS, providing their trenching depth can be accurately set and remain repeatable.

Ray.

 

[Tom K]

Once again, this is another question I would like to reply to as I cut a lot of lap joints, but I don't feel happy replying to a man who has no christian name and I don't know where he lives, some will find this pedantic, but to me, it's nice to know who you're talking to.
Regards,
Rich. (from Reading.)

Sorry. I'm Colin Watters and live near Huntingdon in Cambridgeshire. Going to be building a green oak framed shed as soon as I can get planning permission.

Don't worry Colin,

You've just encountered the village silly person.

Most people on the forum preserve their anonymity - including the moderators!

Nah the village silly person is a Brummy


Regards Tom

 

[dennis]

Colin

There are several good makes of blade and as you will be cutting a lot of oak I would suggest getting the best crosscutting one that you can afford
perhaps others can give reccomendations on ones that have performed well on oak.As Ray says there seems to be a bit of confusion over the beam sizes, and it also depends on which way you are half lapping but as I understand it your half lap is 3inches deep.So if your beams are 6inch by 3inch you would be removing 3inch wide by 3inch deep by whatever length to form your half lap,If this is the case you could cramp 2 or 3 together and cut as suggested moving a blade thickness each time then cleaning up as required.

Dennis

 

[Tusses]

I'm guessing the beams are 6 by 6 ? no ?

also - I'm guessing 'green' oak, which I have heard is very easy to cut .

 

[OPJ]

On my Bosch GCM 12 SD, you can actually fit a lump of timber 6" deep underneath the blade, though I've never tried to cut anything like that on it... Bosch also specify that the maximum depth of cut is about 4".

Tusses, I think it depends on which way you cut the timber. Ripping or cutting along the grain you're bound to encounter problems as the stresses are released from inside the unseasoned timber. Take it steady and you should be able to cut across the grain though.

 

[Rich]

Once again, this is another question I would like to reply to as I cut a lot of lap joints, but I don't feel happy replying to a man who has no christian name and I don't know where he lives, some will find this pedantic, but to me, it's nice to know who you're talking to.
Regards,
Rich. (from Reading.)

Sorry. I'm Colin Watters and live near Huntingdon in Cambridgeshire. Going to be building a green oak framed shed as soon as I can get planning permission.

Don't worry Colin,

You've just encountered the village silly person.

Most people on the forum preserve their anonymity - including the moderators!

Dan, what have I ever done to you? why would you want to say that about me, after I went out of my way to warn you about boxing in a boiler, I'm astounded, you can ask digit if you like, I tried to pm you and even put it out on the forum how dangerous it was, and I'M the village silly person, you should be ashamed at yourself for sinking so low just because someone holds a pedantic view, it certainly did'nt bother Colin watters, who had the decency to reply in a polite manner.

Rich :evil: :evil: :evil:

 

[Anonymous]

Don't worry Colin,

You've just encountered the village silly person.

Most people on the forum preserve their anonymity - including the moderators!

Rather uncalled for isn't it?

 

[Digit]

Yep!

Roy.