Advice on buying vintage Wadkin BRA radial arm saw

[mr_offcut]

Hi guys I'm in the market for a vintage Wadkin BRA radial arm saw. As I understand it they were made in 14 and 16 inch. Looking for the 14".

There is one Kinda near me, but the guy says it's only 9". And the riving knife looks like it is close to the blade, so it looks like that's all it can take. Thing is i can't find any reference to a 9" Wadkin RAS. Did they exist?

Anyone have a 14", could they measure the blade guard?

Are there any specific things to look out for on the BRAs?

Also moving these things, Can two men lift one? Or should it be broken down?

Thanks

 

[guineafowl21]

I only know of the 350 and 450 (14” and 16”). Maybe it’s one of those but has a 9” blade fitted, and custom riving knife? The riving knife is normally removed for crosscut work.

I have a 350. What blade guard dimensions are you looking for?

Check the usual things, including play in the arbour, and also that all the rotation latches work and clamp properly. Often, the clamp levers are broken off, as is the rise/fall handle.

Check for play in carriage rail bearings, and that they are present and correct - play can be adjusted out but new bearings are very expensive.

Two men could lift/drag one, hoist one end onto a trailer/truck bed, and slide it home no problem. Just remember to lock the carriage before starting.

They’re usually three phase - is that ok for you?

Brilliant machines - quickest thing to set up for repeated, accurate crosscuts, and tenons/laps of pretty much any size. I’m actually using mine now for tenoning.

Good for ripping too (14” will do 8” rips if timber is flipped end-for-end), but you must set it up right. Ask here for advice if you want to do that. Many are frightened by it, but it’s all in the set-up.

 

[mr_offcut]

Thanks for your detailed response, exactly what i wanted. It seems pointless to get a flimsy RAS, so I'm glad about your description. Also that it stay at the correct angles. Dados and tennoning were my main motivation over a sliding miter.

I intend to use a VFD, as this will allow the blade to be slowed down if required. I currently have a 'static phase converter' for my 1hp TS. If the motor gets bogged down, the start cap is not automatically re-engaged. While this can be addressed, it actually helps with kickback. If the blade pinches, it stops. You only get to push against 2/3hp. Not saying this setup can be applied to a 7hp motor. But it's probably saved me twice.

Its a 12' x 15' home workshop. So sheet goods are a little difficult to handle, but at the end of the RAS table are doors. A small flap at the side of the doors would allow me to rip an 8x4 (using the small flap door and regular door together like barn doors). I've been reading up on ripping, I think if I follow the safety advice I should be fine. May add some additional start/stop switches, as the typical bench mount type is inaccessible when you have half ripped an 8x4. I should imagine ripping backwards turns it into a terrifying monster & ruins it.

The dimension I'm after is best said with a picture:

 

[deema]

Check the bearings in the track, as @guineafowl21 says they are eye watering expensive to replace. The other thing to check is the spindle, nut and the hex slot in the end of the spindle. The motor is a special, so if it needs replacing the machine is really only good for spares / scrap. The last major item is the bridge casting that holds the motor. Verify it isn’t cracked, they can be if the motor has been removed by an ape. Other than that, they are just about bullet proof.

You will better off with a digital phase converter (DFC) rather than a VFD. VFD’s have a maximum number of switch on / off in a given oeriod which is usually too few for a RAS. The DFC has the advantage you just plug it in and play and can use it for other 3 phase stuff.

 

[guineafowl21]

^ That blade guard looks the same size as mine, in proportion to the other parts of the saw. It looks like you have the anti-kickback bar on the back for ripping, but I’d be looking for a proper riving knife, or make one.

I had one kickback with mine, early on, which would not have been prevented by kickback pawls. The just-cut piece migrated sideways and into the rear teeth, and was propelled right past me. That’s when I made the riving knife, and nice long push sticks.

Re: VFD, my 350 motor is 3hp and was wound in permanent star (400V only). If yours is the same you’ll need a 400V output VFD. I did dig out the star point for delta (240V) use with a normal VFD, but instead found a 10hp rotary converter.

Looks to be in good nick. Snap it up!

 

[mr_offcut]

My TS was permanent star. Had to dig into the winding to get delta. PITA, but its happy now. Thanks for the heads up.

Oh that one is on vintagemachinery.org. The pics of the one in question aren't great, here are a couple:
There is a space between the riving knife and blade, but if it 9" "tooth-to-tooth" then looks like 10 is max? But the proportions look right to me, so no further the wiser?

 

[guineafowl21]

My guard is 420mm as pictured in post #3.

Not sure what you’ve got there. If it is 9” then it might be worth waiting for a proper 350/400 to come on sale.

 

[deema]

There was a dinky Wadkin RAS which the one in the photo looks like.
I might have a factory single phase full size Wadkin RAS that could be for sale which is properly dialed in (it’s my own) if a friend decides not to buy it.

 

[guineafowl21]

You will better off with a digital phase converter (DFC) rather than a VFD. VFD’s have a maximum number of switch on / off in a given oeriod which is usually too few for a RAS. The DFC has the advantage you just plug it in and play and can use it for other 3 phase stuff

Quick thread derailment - before I got the RPC, I looked high and low for a digital phase converter. It’s a confusing market - unless you buy an expensive, pure sine, true DPC, what you often get is a VFD.

For example, there’s one on sale at JFK electrical:
https://www.jfkelectricalni.com/product/digital-phase-converter-5-5kw-7-5hp-240v-in-400v-out/

I ordered one, and the chap rang me to check what I was running. Apparently these won’t run a DC brake, like I have on the RAS, and won’t enjoy the pole switching Dahlander motors on the spindle moulder and power feed.

I’d apparently need an expensive sine wave filter and a much bigger unit to run my machines, pretty much the same overall cost as the pure sine wave, true DPCs.

He was very helpful, and although I cancelled the DPC/VFD order, the service on some other bits and pieces I ordered was excellent.

Just beware of the blurred lines between DPC and VFD, that’s all.

 

[schnapps95]

Hi guys I'm in the market for a vintage Wadkin BRA radial arm saw. As I understand it they were made in 14 and 16 inch. Looking for the 14".

There is one Kinda near me, but the guy says it's only 9". And the riving knife looks like it is close to the blade, so it looks like that's all it can take. Thing is i can't find any reference to a 9" Wadkin RAS. Did they exist?

Anyone have a 14", could they measure the blade guard?

Are there any specific things to look out for on the BRAs?

Also moving these things, Can two men lift one? Or should it be broken down?

Thanks

Hi. We have two of these at work they made in different format's you could get a standard arm or a long arm which enabled you cut an 8ft x 4ft sheet up the middle at 2ft with head turned 180 degrees, also the later ones the arm was more angular, the motor was different and the guard is held on by two wing nuts instead of one

 

[alayagaia]

Hi guys I'm in the market for a vintage Wadkin BRA radial arm saw. As I understand it they were made in 14 and 16 inch. Looking for the 14".

There is one Kinda near me, but the guy says it's only 9". And the riving knife looks like it is close to the blade, so it looks like that's all it can take. Thing is i can't find any reference to a 9" Wadkin RAS. Did they exist?

Anyone have a 14", could they measure the blade guard?

Are there any specific things to look out for on the BRAs?

Also moving these things, Can two men lift one? Or should it be broken down?

Thanks

Had one of these myself, found it somewhat cumbersome and eventually swapped it out for a Festool mitre saw. Depends on what you intend to use it for.

 

[niall Y]

The bed on the illustrated Wadkin looks to be far too narrow to be of much use other than for setting into an existing bench. or between a run of roller benches.

I have to admit that my BRA14, with the more usual sized bench is raised up with concrete blocks under the legs. This gives a better working height for me, though the reason I initially raised it up was to keep it proud of the flooding I used to get in the workshop.

As others have said I would hold out for a more standard version. It is an incredibly useful piece of kit and is probably the single reason I never invested in a tenoner.

 

[mr_offcut]

Sorry bit slow to reply.

Thanks for the dimension 420mm ~ 16 1/2", but 14" saw. The saw in question has a 12" guard. So guessing probably max 10". Think I may pass on it.

There seems to be two table types thin and wide. No connection to saw size AFAIK.

I've done a bit of research on the DPC thing. It looks like it can output with no load, whereas the VFD can't apparently. I guess they use slightly different tech. If you want to buy one device for multiple machines then I guess its a good option. But It doesn't really provide any advanced features to the saw. Like DC brake, soft start and variable frequency. So do VFDs break a lot, or only with very heavy start-stop?

If a DPC is intended for multiple machines, I can't see how it can provide DC braking (unless there's a separate feed for each tool). I'm not too up on DC brake modules or DC brakes integrated in a VFD. As I understand it they disconnect from the supply and put the winding's through some big resistance. So, unless I've misunderstood, a DPC should be compatible with a brake too. But I may have some things wrong?

deema, I may be interested but do understand I can't pay for restored condition. I'm hoping to find one cheap and local restore it. If the motor bearings need replacing with new, then I assume the spin-down time will be ages, and a DC brake would be useful. Safer apparently too, not quite sure how, other than less time spinning, implies, less danger.

 

[guineafowl21]

I have a Crompton S10 DC brake on the RAS (came with it - very expensive new). The rotary phase converter runs it just fine, although I had to retune the braking force and time when I moved away from the shop with real three phase.

It’s set down low so I can turn the saw off with my knee, keeping hold of the carriage and workpiece, which is good.

I looked into VFDs with braking resistors, but they seemed expensive.

The 14” blade is heavy, and takes ages to spin down without the brake. When you’re in a rhythm, there’s a tendency to get your hands in, moving the pieces around as soon as you’ve made the cut. Try to get into the habit of using the timber to knock the offcut out of the way, not your hands. Just never place your hands in the saw path - there’s no need to.

The spinning saw blows a lot of air around, so if there’s a stray offcut in range of the blade, it could be blown in there and cause the saw to climb forward. If the workpiece is long, it can tip upwards after being cut. At least with the brake you can minimise any hi-jinks.

If your RAS is not very level, the carriage can creep forward too. A retractor reel might be a good idea.

 

[deema]

The ten second stopping time requirement came from an analysis of accidents. What I understand became apparent was that in industrial use, operators tended to stick their pinkies into machines before the sharp bits had stopped rotating. The standard was to reduce the wait time to a maximum of 10 seconds to reduce this tendency. So, from a safety perspective, if you are not prone to being fixated with sticking your pinkies into rotating blades (some people do have a weirded fascination with ‘I wonder what it would feel like’) then braking isn’t going to reduce the mess if you stick your fingers in when it’s switched on. I say that as there seems to be a perception that if you stick bits in and then hit the stop button the 10 seconds stopping time will reduce the mess……it won’t, that damage is done long before you think of where is the stop button!

My friend will hopefully decide on whether he is having the saw in the next couple of days. It’s not a fully restored saw, so it’s not ‘better than it came out of the factory’ condition which is what @Sideways and I always try to achieve on our restores. This is my user saw, so it’s in as it came out of the factory condition, tinkered with to ensure it cuts properly and precisely. Ie the paint work is original. The price will, reflect the cost of what I paid for it, not the time I’ve spent getting it spot on.

 

[duke]

Had one of these myself, found it somewhat cumbersome and eventually swapped it out for a Festool mitre saw. Depends on what you intend to use it for.

RAS does serve a good purpose for myself, I have a dado blade set at 19mm for shelf and cabinet work or whatever need requires.

 

[mr_offcut]

Thanks guineafowl21 for that tip about the saw to climbing forward. That was non-obvious (to me at least) so learned something new. deema, I will wait to see what your friend decides.

Ok So I did a bit of reading on braking modules. 10s is a bit underwhelming. It looks like they have duty cycles, which annoys me. According to what I've read the motor can spin down at the same rate that it spins up. The power and consequently the heat in the winding's is the same. It's usually above the rated amps of the motor, but is momentary.

According to this: https://circuitglobe.com/induction-motor-braking.html
'Zero Sequence Braking' is one of the best methods.

This has more info, calculations, and in conclusion, a 100-300uF capacitor is required https://scialert.net/fulltext/?doi=jas.2012.2616.2620.

I found some of the diagrams confusing, so this may work:

Not tested. Disadvantage is that you have to split P3a and P3b in the motor. Not always easy. As I understand it, because the motor is turning, the coils produce a voltage similar to three phases mixed. This charges the capacitor, which produces a voltage to stop the motor in a feedback loop. I'd appreciate any feedback, maybe I've missed something...

 

[guineafowl21]

10s is fine in practice. If you want it quicker, you can adjust braking force and time.

I’m not sure about what you’ve posted above, but bear in mind that very rapid braking like you describe could undo the blade nut by inertia.

My blade clamps are locked to the spindle, but the nut isn’t. This is fine under gentle braking.

If you want hard-stop braking, you might have to modify the shaft similarly to modern spindle moulders, where the shaft is slotted to accept a washer with lugs, and the whole lot is clamped with a countersunk allen screw.