Advice on DW RAS

[John2905]

Hi

I have recently bought a DW125 RAS it fairly good condition apart from having no table timbers. These are obviously quite easy to make from MDF but I do not know what the sizes should be for each strip. I can,to seem to find size details anywhere. Can any one help with these dimensions please or perhaps a link to more info ?

John

 

[DaveL]

Hi John,

Welcome to the forum.

I have split your post off the old thread, you will get a better response with a new one.

I don't have any sort of RAS, but hopefully someone will be along with some useful advise.

 

[mailee]

Hi John, I have the Elu version of this saw and it is identical. It is a little late now but first thing in the morning I shall go to the shop and measure them for you. Speak soon. :wink:

 

[mailee]

Hi John, OK here are the dimensions of the table:
Table is 48" wide and the first section behind the blade is 6" deep. In front of this but still behind the blade is another piece which is 2" deep. Then the fence which on mine is 3/4"thick. Then in front of the blade is the main table which is 18" deep. I hope this helps you. :wink:

 

[John2905]

Hi mailee

Many thanks that is just the detail I needed.

Regards
John

 

[Joe90]

Hi

On a machine like that you have to provide your own fence, is this correct? How then does one ensure that the fence is perpendicular to the direction of travel of the blade? :?

I made my own 'RAS' by making a base for a spare Makita 235mm circular saw I had and putting it on 1000mm ball bearing runners I also had... :shock: it is very good in that it runs smoothly with minimal side to side play and has about 800mm of cut... 90 degree cuts only. I only use it occasionally for the odd piece... I really want to buy a proper one when I see one second hand, several people say they have a RAS for sale when really it's a SCMS. :shock:

The problems I always have though are setting up the back fence so that it is exactly perpendicular to the travel of the blade... also it's difficult to see where the saw will cut but I have a scale taped to the fence which works pretty well...

Any help would be appreciated...

 

[mailee]

Hi Joe, On the true radial arm saw the swivelling post is adjustable to give you a true 90 degrees to the fence. I usually run a cut along the table just breaking the surface and then use a good square to adjust the arm. I never use mine for mitre cuts as I made a jig to use on the table rather than disturb the settings. They do tend to go out of adjustment on a regular basis but if you keep them adjusted rgularly they are a great saw. I would not be without mine now and this is the second one I have had. I prefer it to a SCMS but it is personal choice really. To do the same job as the radial arm it needs to be a BIG SCMS and they are around the same price as the radial arm. Scrit is the one to quizz as his knowledge on these is second to none. :wink:

 

[Scrit]

On a machine like that you have to provide your own fence, is this correct? How then does one ensure that the fence is perpendicular to the direction of travel of the blade?

Well you go through fences and base boards so it is normal to make the fence from something like 22mm thick beech, pine, whatever is to hand as the centre bit won't last. Similary it is a good idea to cover the top surface of the table with a sheet of hardboard or 4mm MDF as a sacrificial top. This is much cheaper than sawing into the plywood table surface. As mailee says there is a convoluted process to setting up the DW RAS which needs to be followed exactly to ensure accuracy. It starts with the blade/guard being removed and the arbor is then tilted to the vertical, pointing downwards. The arm is swung from side to side and the table is levelled to touch the bottom of the arbor. If you don't do that first then all the other set-up processes are a complete waste of time. The prpocess is the same for all the DW saws (an incidentally just as applicable to Ryobis, Eumenias, Wadkins, Stromabs, Maggis, etc) and is in all of the DW RAS manuals. Once the table is level the blade needs to be set vertical, the arm squared to the fence, etc.

The problems I always have though are setting up the back fence so that it is exactly perpendicular to the travel of the blade... also it's difficult to see where the saw will cut but I have a scale taped to the fence which works pretty well...

The five cuts technique used for panel saws can be used. Take a look at this thread (smacks of "here's one I prepared earlier"..... :roll: ) and you'll see what I mean. Starting from a single straight edge if you make squaring cuts and turn the just cut edge in to the fence each time if your last cut cuts a 3 to 4mm wide strip (at the fence end) and discrepancy will be magnified by the process and corrective action can be taken.

Having looked at the issue of the RAS going out of whack I'd say this: it doesn't happen on industrial RASs, it does on home shop machines. I believe the reason why is to be found (partly) in the arm on the hobby machines being lighter, but has much more to do with the general build of the sheet metal base to which the column is attached. They are simply too light and will flex when any out of square load (such as cutting a mitre) is put on them. I've had a table fabricated in the past for a DW1751 which cured the almost all of its ills - it was made from 3mm thick channel section. The problem area has to be the two front to rear folded steel channels to which the arm is bolted. If these could be stiffened by adding a snug-fitting plywood box section between them and possibly by bolting two thick channel sections down the outsides then I'm certain rigidity would be much improved and with it accuracy after cutting mitres.

Scrit