Trenching head for Wadkin BRA?

[Guineafowl21]

A request aimed particularly at our resident machinery spotter...

Looking for tooling for my BRA 16 (1”bore) for making housings, in plywood/MDF as well as normal wood, so I guess carbide tips are needed. Housings from about 10-25mm would be handy.

I have an old 6” wobble saw, but it has a well worn 1 1/4” bore so the reducers are a bit of a shaky fit. Also produces curved bottom housings so not ideal, and the tips are on their last legs.

Amateur use so a brand new tool is a bit out of price range. I just need more shelving, and am planning a chest of drawers made with frame/panel housed to accept web frames. Also might be handy for quicker tenoning.

Any suggestions much appreciated.

 

[9fingers]

5/8" dado head bored out to 1" maybe.

Bob

 

[Trevanion]

A request aimed particularly at our resident machinery spotter...

I wonder who that is :eusa-think:

So, Wadkin originally offered sets of trenching cutters for the BRA which I’m sure you’ve already seen, made from gunmetal with bolted on knives and knickers. Now, a set of these would be ideal but the unfortunate thing is that they’ve become a serious collectors item, even for people that have no intention of ever running them, and so they now command a premium on the likes of eBay especially if there is international bidding as they are highly sought after the world over (You have Jack Forsberg to thank for that!). They’re relatively rare and don’t come up for sale that often as say old Whitehill blocks, but I’ve seen clean sets fetch over £250 on eBay in the past which is quite a ludicrous price in my opinion for quite old tooling, especially as quite a lot of these sets haven’t been particularly looked after in their previous lives and can be quite worn out, which can make them dangerous to use, as well as spare parts being non-existent. On top of that, while they work really well when setup correctly, they are a bit of a pain to get set so that they’re working correctly as you have to set each knife and knicker individually with no method of easy adjustment.

Personally, if you really want to trench with the radial arm saw you’re going to have to look at a new groover, I would imagine the best place to get one would be Whitehill as I would guess they’ve made quite a few for BRA operators over the years. It won’t be a cheap option by a mile though as it will be a big chunk of metal at about 8”-10” in diameter, but they’re a much better bit of kit compared to the Wadkin ones as there’s no faffing about with the knives and knickers. You could also pick up the CMT Dado blade set from Scott and Sargeant which would be a good option as they’re not too expensive, still a bit of a faff to set up and you’ll need some kind of reducer sleeve as they’re 30mm bore.

https://www.scosarg.com/cmt-230-dado-set-d-200-b-6-35-22-23-d-30-z24

Alternatively, Wallace might have a spare set or know someone who does.

 

[wallace]

I had a clear out of stuff a couple of month ago and had 3 sets of the gun metal wadkin trenching heads. I think I sold them for £80 a set. I think they were off a EKA tennoner so too big for a BRA.

 

[Guineafowl21]

Thanks. A proper Wadkin head would be nice, but would the HSS knives survive plywood for long?

Those variable groovers are good, but pricey, and a bit restricted in range perhaps.

A dado stack sounds a better option, possibly 30mm bore as it’s easier to sleeve them down than to bore out, unless I send them over to Doubleboost John. They would also need drilling for a drive pin if I’m to use the DC brake.

 

[9fingers]

I only suggested boring out as it would be a job to can do on your new lathe?

Bob

 

[Trevanion]

Thanks. A proper Wadkin head would be nice, but would the HSS knives survive plywood for long?

Probably not, the glue used in plywood is very abrasive on cutters, you can cut miles of hardwood with a saw without much issue but a few sheets of plywood, MDF, or OSB really wears out blades. I think Wadkin offered either Stellite or Carbide tipped blades for the job to fit their heads.

A dado stack sounds a better option, possibly 30mm bore as it’s easier to sleeve them down than to bore out, unless I send them over to Doubleboost John. They would also need drilling for a drive pin if I’m to use the DC brake.

I’d personally just use a 25mm to 30mm sleeve that’s as long as the maximum size of groove that can be used then use spindle moulder spacers to take up the slack between the nut flange and the end of the sleeve when doing narrow grooves. You could drill holes in the plates but I’d personally run it without the brake.

 

[Guineafowl21]

I only suggested boring out as it would be a job to can do on your new lathe?

Bob

Could be...I’ve already had a few jobs come my way once word got out I had a lathe.

Would you bore each blade (and shim?) individually, or make up a 5/8” mandrel, and use that to centre the whole stack on a faceplate?

 

[9fingers]

I did mine one at a time. I was always taught that machining multiple items as a stack was bad practise and open to errors.
Make a reference go no go plug gauge for your spindle size.
Bolt a ply wood disc to the faceplate with deeply csk bolts. Skim the ply to get it running true and put a 3/4" hole/recess in the centre. Machine a rebate around the circumference to accept the carbide teeth with clearance and so the blade body was flat on the ply. Assuming your tailstock is set up properly on the lathe axis, use a centre to press the blade onto the ply. Secure with 4-6 equally spaced woodscrews and washers in the gullets of the outer cheek dado blades. Bore out the centre, checking with your plug gauge as you go.

Rinse and repeat for the other cheek and chippers.

hth
Bob