Radial arm saw setup and use? (accuracy)

[bigegg]

See this is what i thought. And its not even a "pin" as in round pin, that could ware, and get slack, but a wedge that 'pins' into a slot. So ware is taken out, and the wedge will center to the same point again.

But that is in contrast to...



So im still left wondering! : )

The wedge only locks one joint.

You swing the arm by 45degrees, and that puts a side load on the upright pillar which can move it by 1/2 a degree.
That flexes the table, and twists the fence.
The side load moves the yoke slightly.
Then you move it back to 90degrees, to find that everything's out by a millimetre across the 12" cut, so you spend 20 minutes re-squaring it all again.

 

[Johnseat]

I've had one and sold it, trust me the wedge doesn't guarantee it will locate exactly back to where it was.
You go to a wood workers shop and have a look at their RAS bench (that's if they've got one!) and take note of the back rest, the groove for the 90° cut is huge due to the movement.
Also I wouldn't use timber or sheet wood for the bench top as it warps all over, I'd use a thick melamine.

 

[Turbo]

I'm reading this with interest as I recently acquired a Dewalt RAS similar to the Julians - might be the same, mine has lost its sticker. I'm unsure what to do with mine as it needs some attention - most of the clamp levers are seized, some are broken, probably from ham fisted attempts to move them. It's also 3 phase so I'll have to botch up some capacitors to get it running.

It's also quite large & too heavy to move around so needs it's own dedicated work space, something I currently don't have available. There is one shed I was going to turn into a woodwork shed but Dad put his hens into it while he treated the henhouse for mites & he has no notion of moving them back again!

I see why it's not a good idea to swing the arm on the column for cutting mitres but what about tilting the saw blade to cut an angle along the edge of a sheet, eg if you were making a large wooden box & wanted to mitre the joints between the sheets. Does tilting the saw blade knock out the accuracy badly?

Apologies to Julian if it seems like I'm hijacking your thread but I think we both might be looking for similar help. What I've read so far in this thread has answered some questions!

 

[bigegg]

I'm reading this with interest as I recently acquired a Dewalt RAS similar to the Julians - might be the same, mine has lost its sticker. I'm unsure what to do with mine as it needs some attention - most of the clamp levers are seized, some are broken, probably from ham fisted attempts to move them. It's also 3 phase so I'll have to botch up some capacitors to get it running.

It's also quite large & too heavy to move around so needs it's own dedicated work space, something I currently don't have available. There is one shed I was going to turn into a woodwork shed but Dad put his hens into it while he treated the henhouse for mites & he has no notion of moving them back again!

I see why it's not a good idea to swing the arm on the column for cutting mitres but what about tilting the saw blade to cut an angle along the edge of a sheet, eg if you were making a large wooden box & wanted to mitre the joints between the sheets. Does tilting the saw blade knock out the accuracy badly?

Apologies to Julian if it seems like I'm hijacking your thread but I think we both might be looking for similar help. What I've read so far in this thread has answered some questions!

The blade tilt/twist doesn't tend to be so bad - on mine at least!

If my previous posts seem to be badmouthing the RAS, then that was not my intent - it's a fantastically useful bit of kit which I use on a regular basis.
The accuracy can be had, and repeatedly, but it does have limitations which have to be worked around. Perhaps it's just mine? Yours may not be as bad- I have a black and decker powershop RAS (same design, different stickers).

The biggest issue is, to my mind, the pressed steel table box -I have had plans to fill it with concrete for a couple of years, but at the moment, it's still "on the list"

 

[julianf]

The biggest issue is, to my mind, the pressed steel table box -I have had plans to fill it with concrete for a couple of years, but at the moment, it's still "on the list"

I had a look, and the pillar just bolts on to it, so, rather than filling the box, why not just replace it all together?

 

[bigegg]

I had a look, and the pillar just bolts on to it, so, rather than filling the box, why not just replace it all together?

Cos I'd replace it with a cast concrete table, so might as well leave it in as reinforcement.

 

[julianf]

Two more questions...

Being a welding forum, how come you (plural) even bother with wooden tables? The mr sawdust thing has metal strips set into wood, but why not just weld up a frame out of box (etc) and bolt a bit of mdf to the top? The average wood person probably does not have a welder to hand, but most people here do, so why bother with bendy bits of wood, etc?


Second -

Ripping -

I understand that it could all get adventurous with ripping from the wrong direction with a RAS, but if the wood is pushed toward the rotation of the blade, then its never going to grab, right? And if the guard and / or finger things are low, then im thinking it cant lift the job either?

The reason im asking isnt to be smart - far from it. I dont have a table saw. I do have a RAS, but it needs some time and money on it before its up and running. But, without being able to rip, then its kind of nothing more than a space inefficient chop saw to me.

Im wanting to do the rebates on these bits of oak i was on about in the other thread.... And one of my timbers is bowed also, so i need to rip the side of it too, to straighten it up.

 

[brewdexta]

Two more questions...

Being a welding forum, how come you (plural) even bother with wooden tables? The mr sawdust thing has metal strips set into wood, but why not just weld up a frame out of box (etc) and bolt a bit of mdf to the top? The average wood person probably does not have a welder to hand, but most people here do, so why bother with bendy bits of wood, etc?

I did the Mr sawdust table as it utilises the legs that fit on the base which I already had, but as Bigegg mentions, the saw base can flex a bit, it can probably be sorted. I didn't want to build a bench for it but it would be a good solution if nice and solid and you could use the same flexible fence system that Mr Sawdust advocates. I may end up getting rid of the RAS and buy a sliding mitre saw, but not yet, the tool kitty is empty.

Second - Ripping

I can't help you there, I have a table saw I use for ripping.

 

[eLuSiVeMiTe]

Cheap table saws come up regularly.
Wouldn't want to rip on a Ras if it snatches ..... Table saw pulls down. A Ra's pulls horizontally.

Need a floor standing jointer really. Can't rip a bow out of a timber against a fence it follows the bow. Plane true rip against the true edge. Ping a string line and use a skill saw in a pinch.

 

[bigegg]

I can't help you there, I have a table saw I use for ripping.

I've done ripping on the RAS.
It felt unsafe, even with the fingers down.
I managed it,but the slight flex is just enough to make it feel like it's constantly going to grab.
As I said, could be just mine - it does need a bit of fettling.

 

[bigegg]

As to the table thing - a nice 4ftx18" cast iron surface plate with 12mm of MDF on top would be perfect.
A welded space frame to replace the sheet steel box would also work - but concrete would work better, and be easier to make.

Just because this is a welding forum, doesn't mean that welding is always the best solution - I believe the original 1940s/50s de Walt's had cast iron bases with solid wood tables.

 

[Onoff]

Mine has a table made from MDF painted with yacht varnish. Supported both ends by some 50dia, 6wall st/st tube.

I do like to keep things tidy:

Just had to sketch the wiring diagram for a lad who'd bought one spares or repair if anyone's interested:

Tbh I've just nicked the capacitor from mine for my gennie!

Safety first, NEVER wedge the guard up:

I agree btw, useless for ripping!

 

[bigegg]

Cheap table saws come up regularly.
Wouldn't want to rip on a Ras if it snatches ..... Table saw pulls down. A Ra's pulls horizontally.

Need a floor standing jointer really. Can't rip a bow out of a timber against a fence it follows the bow. Plane true rip against the true edge. Ping a string line and use a skill saw in a pinch.

Clamp it to a piece of plywood, and run the straight edge of the ply against the saw fence - on a table saw, not the RAS!

 

[eLuSiVeMiTe]

Noted for future use. Cheers. Good idea.

Clamp it to a piece of plywood, and run the straight edge of the ply against the saw fence - on a table saw, not the RAS!

 

[DennisCA]

I don't know much about these saws but Frank Howarth on youtube has several and has some interesting setups wit build in dust collection, with videos of him making them.

 

[julianf]

Noted for future use. Cheers. Good idea.

In theory -

If the fence is at least double the length of the job, and you run the concave side along the fence, then it will not rock.
This would allow you to cut the convex side straight.


I had assumed the issue is exactly the same when using any saw with a fence? I cant really see why the rocking / bowing thing would be any easier with a table saw?