Sliding Table Saw

[thomas169]

Hi all, I'm a new poster and fairly inexperienced woodworker here.
I'm looking to get a table saw for building speakers enclosures and from my limited experience have decided that I need one with a decent sized, accurate sliding carriage. A small footprint and low weight would be nice but are of less concern, and I also can handle 3 phase if needed but would rather not.

I've browsed eBay and am pretty sure I'll need to get something used (which is no problem) if I want to stay in my budget of about £400 and get something that fits my criteria. I've looked at some fairly big old Wadkin saws and they do look good but maybe a bit heavy and possibly overkill.

I'd appreciate any advice, especially any names or features to look out for.

 

[BradNaylor]

As you say, at that price you are looking at second hand, but you should be able to find something to fit the bill. Looking at what is available on ebay at the moment, these are my comments;

link

This is a nice saw, reputable make, and it is single phase. Unfortunately, it will fetch well over a grand - single phase machines are very sought after. Keep an eye on it though, you never know!

link

If you've got the space, you could do a lot worse than one of these. They are accurate, heavy duty, and reliable. Best of all, no-one wants them because they are so old fashioned. This makes them cheap! I wouldn't mind betting that this one doesn't get any bids over £400, particularly as the idiot who listed it has spelt 'panel' wrong, meaning most people won't find it in their search.

linl

This is almost identical to my saw, but ridiculously overpriced! I paid £350 for mine from a joinery shop that was closing down. I can recommend SCM saws if you can find one at the right price.

link

I like this one. Maybe a bit small for big sheets of ply, but a much better bet than a new Chiwanese saw for £800.


All in all, you really need to be looking at 3-phase machines to get a decent saw for £400. You may well be lucky on ebay - a private sale is what you need. A dealer selling second hand gear is going to be charging a hell of a lot more than you want to pay.

Good Luck

Dan

 

[George_N]

The other option to consider for cutting sheet material is The Festool system (or other hand held saw/guide rail combo). Similar price tag as a second hand Wadkin and just a tad lighter.

 

[thomas169]

Cheers guys,
So far I've used a circular saw and DIY sled, and although that Festool system looks good, I'm looking to move away from using a circular saw for all of my cuts. I hope/think doing so will give quicker and more accurate cuts (?).

I do have a small B&Q table saw but it proved worse than useless of almost any type of cutting I was after, and so has been lying unused since I got it, time to sell on it on I reckon.

Dan, Thanks for the list, two of those saw are located in the North East which is good for me but sadly they appear to be the two that will likely be out of my budget. Something like that big old Wadkin you mentioned is very tempting tho, and atm seems to be the best option for the job, I assume it will give me the, large accurate cuts I'm after, if only it didn't weigh as much as a small house, I’d go for it right now.

 

[Tusses]

It depends on what kind of speakers you are wanting to make ?

all need air tight rattle/vibration free joints which is best achieved by glueing and screwing/nailing then caulking the inside. standard 'furniture' joints are no good !

PA - really just need to be fairly neat, and most any saw will do with plenty of support all round and some way of making a fence to guide the sheet through

Car - again about any saw - as you will no doubt cover them in carpet or cloth.

Hi end HI-FI on the other hand need to look like a peice of furniture ! but are a lot smaller so you dont really need to be ripping 8x4 sheets to your finished size.

there are jigs and fixtures you can make so you can have your 8x4 sheet vertical - leaning up against the wall, and a good circular saw with a good (the correct blade) will do an excelent job and do it easily and in a very small space !

remember - if you want to size an 8x4 sheet on a table saw you need at least 8' infront and behind the saw and 8' to one side and 4' to the other. thats 16'x12' that you need clear, to work in !

take your time not to buy the 1st saw that you find - and think about the circular saw with a panel cutting system again !

 

[thomas169]

Its is for large P.A speakers mainly, I paint them with a textured roller and thick black speaker paint, so ultra smooth cutting isn't required as it ends up getting quite a thick coating. Thing is with my circular saw construction atm, is slow and a bit of a pain with all the clamp and then reclamp stuff I have to do. Since lots of the cuts I make are long bevel cuts the guess work that is involved with my saw is the main cause of any errors in my cutting. I'd like the table saw to be able to cut 4x4 sheets and do accurate bevel cuts.

If I read the festool saw information right it claims there is zero clearance from saw to guide rail even at an angle. This would be a huge help and quite a draw for me as this is one of the main reasons I'm not happy with my current setup. Would one of these and a piece of ply to use a cut table really be a suitable alternative to a table saw?

Cheers
Thomas

 

[Tusses]

I'm surprised there is still a market for those since the moulded plastic ones came out !

I used to make them years ago. The mid/high range and some of the low/sub you could do with a TS but you need a lot of room for the big stuff as I said.

I have only read about the festool system - but from what I have read , it sounds like it would be better than a TS for your setup. It'll be worth reading up on it and finding somewhere that will demo it for you.

oh - not wanting to teach granma about eggs n all that - you know you get a better sound from MDF or chip board ! just have to protect the edges/corners.

 

[thomas169]

Tusses,
Those moulded plastic ones tend to be budget speakers which isn't much like what I'm building also if you look at any of the large, good quality P.A speakers you won't find many plastic ones, at least I haven't anyway.

I'm not sure why you would get a better or worse sound from MDF (density?) providing the cabs are all well braced. I was told the birch ply I use is stronger, lighter, and more resistant to moisture. Though the cabs are large I try to keep the weight down as much as possible with Neodium drivers and where appropriate using 12mm ply with extra bracing rather than 18mm stuff.

Saying this for permanent installs I wouldn't hesitate to use MDF, since it is so much cheaper than Birch ply (I pay £40 a sheet, and thats with a small discount), and if you're right have some sonic advantages. It's mainly becasue it’s less robust and heavier than ply that I dont use it. Since I use the speakers for hire and free parties these are important conciderations.

Oh and the more I look at it the more tempting the Festool becomes.

 

[neilyweely]

with speakers it is all about the density of the materials used, so yes, mdf is the kiddy. I bought a load of one inch thick stuff to use on the boxes I have been commissioned to make for a shop over the way.

Some high end stuff is made from concrete, as it is so dense and rigid. The other thing to consider is the effect of the air movement inside the box, you get a lot of distortion with the standard square box as the air moved by the driver affects the movement of the driver itself ( it kinda bounces off the back of the box and hits the driver again).

I am sure you know all of this anyway, but with regards to the materials used in manufacture you need to consider density and rigidity. Bracing can help, but unless you are going to use a lot of bracing, which may affect acoustics, you need to use a very rigid material anyway.

I found a lot of information on design on the net which I used to make some of my boxes, and they sound better than cabinets I have heard costing more than a grand.

cheers

neil

 

[Tusses]

birch ply isn't so good. - its too stiff. imagine tapping on the side of an acoustic guitar ! that is the extreme , but is the same principle

the reason for MDF or Chipboard is that is is sound dead. it doesn't 'ring' and tends to dampen resonances . Like if you get your calculations wrong and get the air volume to resonate at a frequency the box uses, then you get a loud boom every time that note appears in the sound source.

Making the cabinets lighter makes for a worse speaker as the cabinet walls can move easier - depending on the frequency bracing is of no use at all , if , for instance, it is placed at a multiple of the frequency harmonic node.

you will find yourself cutting the frequency in half the more bracing you add , so in the end its best to use a more 'sound dead' material. I would recommend at least 1" thick for the base cabs !.

yours might sound good - and they might be better than is needed - but place two designs side by side and you will tell the difference

 

[thomas169]

I don’t make direct radiators which are likely to be the cabs that will suffer most from standing waves forming and vibrations in the rear chamber. The chambers in the back of horns are smaller and as such suffer less panels vibrating, but I still fill them with wadding which helps to reduce standing waves and I try to keep the dimensions of it fairly close to the golden ratio.

Movement of panels is wasted energy and no top of that does cause colorations at certain frequencies but extra bracing will help to reduce the effect of this problem since the smaller the distance from supports reduces vibration (this is where the rigidity of birch actually helps). Since the extra bracing that I have to use is mostly in the horn path it doesn’t’ raise low frequency cut-off to the extent it would in a direct radiator speaker box.

Even if I was building direct radiators I'm still not sure I use a certain type of wood (MDF) to reduce resonances, I'd think the better option to use wadding and get the other benefits that stuffing a cab brings, (increased volume as perceived by the driver) and then whatever wood was best for the job.

I am aware though that using a thicker walled heavier cabinet wound give a better sound, but since these aren’t hi-fi speakers there must be some compromise in the weight (portability) / sound quality balance. Building any speakers other than large HiFi things is always going to be a compromise between size / efficiency / and LF cut-off. Even if it they did sound slightly better made of MDF the other trade off’s when used in the cabs I build and for their purpose are for me not worth it. Of course others have defence concerns and MDF may be the better option for them.

I'm not against using MDF its just I struggle to believe it sounds NOTICABLY flatter, it may cause small changes when measured with an RTA relative to MDF, but I nor anyone I know has such accurate ears as I’ve said . Our hearing isn’t all that sensitive to small changes in amplitude vs. frequencies plots anyway. They are far more sensitive to time alignments issues and phase problems instead.

 

[thomas169]

On topic I've decided I won’t be going with the Festool system, but I do now have a bit more money to spend, about 700 max.

Also for what I’m doing is there any real benifit or need for a saw with scribing blade.

 

[JonnyD]

I find its very handy to have a scribing blade for Melamine faced chipboard and the cheaper far eastern type plywoods. With the right type of blade in a decent machine i think you should be able to manage without the scribing blade.

jon

 

[BradNaylor]

I know nothing of the acoustic properties but I would have thought that for PA cabs birch ply was the best bet.

I know from my days playing in a band that PA cabs get abused. MDF or chipboard would just not stand up to the punishment.

As for scribing blades; for birch ply I would use a good quality cross-cut blade and have it sharpened every couple of weeks. (Therefore you need two)

A scribing blade is then unneccessary.

Cheers
Dan

 

[Scrit]

To point out a small innacuracy, the blade is a scoring blade.....

As to whether or not you need one I think your budget precludes one in any case. They are advantageous if you are dealing a lot with veneered boards, e.g. veneered MDF and I've found the quality of cut on plywoods to be very good, but as Dan points out similar results can be obtained by using an appropriate blade on either a power circular saw or a standard table saw.

The main advantage of a panel saw is that (a full size one) can easily break-down standard 8 x 4ft sheets of material. If your workspace doesn't run to that or you don't have sufficient volume it may be as well to get the merchant to do your initial breaking down and utilise a smaller machine with appropriate blades.

Scrit

 

[BradNaylor]

Scrit,

Did you just agree with me?

:shock: :shock: :shock:

Dan :lol:

 

[Tusses]

I know nothing of the acoustic properties but I would have thought that for PA cabs birch ply was the best bet.

forgetting the acoustic properties - birch ply is a very good choice !

the stuff we've used in the band over the last couple of decades has been mainly chipboard. comes in a van with a sound crew and engineer - we just turned up and play - if its hired out as a unit including engineer then there is no problem with 'on the road abuse' .

I have seen ply used - and depending on the type of music - the sound isn't too bad.

 

[andyavast]

some of the best PA speakers I have heard have been baltic birch ply. I have a lovely sounding and quite expensive speaker cabinet for my guitar amp and it is constructed with 25mm Baltic Birch ply also... sorry if this is off topic thomas.

Andy.

 

[thomas169]

Well I just this evening took delivery of the Electra begum PKF255 that was mentioned by Dan in the first reply. So far (I've not cut anything yet) it looks good and is so so quite compared to my old table saw. No mount for the mitre fence tho so I'll be trying to source one of them in the next couple of days.

And if I was asked to build a speaker for permanent install I would likely use MDF.

 

[BradNaylor]

Nice one, Thomas.

How much did you get it for? You must have made a decent offer to get it withdrawn from the auction.

Cheers
Dan