RB4 Page 2

In this section we will take a closer look at the Box Beam.

	This is a photo looking down the right hand end of the Box Beam. The Beam is a standard size for all models which vary in the length of the sliding bar. It is 32" long by 5 5/8" high by 5 1/2" deep. The section is 1/4" thick. High quality silver anodised inside and out. There are no angled corner fillets so time will tell how stiff the beam is. There are a total of five T-slots so more than enough for even the most avid of jig makers!
The real innovation with the Router Boss is way the sliding bar is mounted. It is fully adjustable for play and is very smooth in travel. Here is the lower travel way. A square section stainless steel bar sits in a V-groove in the beam and the sliding bar has a plastic extrusion which runs along the steel strip. The runners do benefit from some dry PTFE lubricant.
	This is the upper mount which is adjustable. Screws from the front are threaded into the pointed adjustment strip to lock it after depth setting from the beam top. That strip engages with a similar plastic runner to the bottom mount. The adjustment bar can be moved up or down to remove play. The T-slots are generous at 1/2" wide with the front gap at ~1/4". I have checked and 6mm bolts easily fit through. Making up metric T-slot fixings will be easy. For instance I filed some flats on a 6mm domed head bolt which slipped into the slot. The flats stopped the bolt from turning. A packet of 5 mm oval T-slot nuts are provided in the kit.
The rule recesses house the adjusting bar locking bolts. Three of which can be seen here. They only require loosening so the bar vertical position can be set by grub screws from above. Notice the holes in the sliding bar. The fence does not have to be mounted at the end but in any one of the drilled positions. In fact Lewis suggests initially using the third mounting holes in from the left.
	To set the adjustment bar first slacken the locking screws shown above and then gently turn the height setting grub screws to find the smoothest travel without play. They are in the top T-slot. Finally tighten the front locking screws.
Perhaps it is just incidental but the travel handle folds like this. Not sure if there are any operational advantages though.
	The handle has a good throw so accurate tracking should be easy. Since the grip part of the handle turns on it's spindle it will be kinder to the fingers than a plain metal bar.
The sliding bar is activated by wire control. The wire is passed three times around the drive shaft under tension.
	The drive shaft runs in plastic bearings top and bottom of the beam and is positively prevented from working its way out by a C-clip in a groove as shown here.
The drive wire runs over a free running plastic drum on a shaft at the other end of the channel.
	The drive wire is trapped between two steel blocks as shown here on the left side....
...and tensioned by a bolt with this arrangement here on the other end. The screw holding a plastic cylinder above is a travel stop block.
	The rear dust extraction takes waste from the front shute and passes it out through this plastic moulding in the rear beam section.
The extraction pipe just pushes into the housing. The end of the pipe has an external diameter of 65.4mm (2.58") and 58.3mm (2.3") internally. I have two vacuum pipes that fit with a bit of pushing. You may have to adapt to suit.
	A choice of rules or white metal strips can be placed and screwed into the Beam recess for precise tracking. By a clever positioning of the fixing screws the rules can be set inboard or outboard of the beam. This flexibility combined with two positional cursors in the kit should cover all eventualities.
Three of the tiny Phillips screws secure the rule when set inboard but only two when set outboard. As you can see the rules are in metric and inches and increment from right to left. The screws are tiny though so care will be needed not to lose them!
	Here is a white painted 'storyboard' metal strip installed inboard. The strip takes pencil marks surprisingly well.
The plastic cursors are a smoky translucent grey and specially moulded to fit the slider recesses. The inner edges of the viewing window are angled making it easy to accurately line up to a mark. The outside edges work too plus there are internal central notches which work well combined with a ruler. Additionally there is fine slot at the top of the cursor for those who wish to use a very fine pencil and mark directly onto the beam.
	The cursor is secured by plastic finger screws and oval T-slot nuts so can be slid into any reference position on either side of the beam. A set square can be used to align the cursor vertically.
Here is the single fence which is black anodised. It is 8" long with a two inch clamping face. Approximately 1/4" thick. It is a little 'slippy' and Lewis suggests sticking on some abrasive sheet to give extra grip. There is not much of a stiffening curve on the back so there could be some movement when heavily clamped. I will find out when the machine is tested. Having said that I do like a flat back so that I can employ an extra clamp if needed. There is sufficient metal to permit drilling screw holes and fitting a wooden cheek face if so desired.
	At the moment the fences are direct extrusions but look ...... dead square. I understand future versions are likely to be machined. Not really required if they are all like this.
Another plus point! The top and face of the beam are square. In fact very square along the whole length. Certainly impressive.
	A rear view with a spirit level on the box section. Dead flat with no bends or twists. Not bad for a straight extrusion.
This is the set of keys provided with the kit. They are OK and do the job but I find them a bit fiddly to use.
	Imperial Allen keys are becoming harder to find in the UK but I have purchased some high quality, longer ball ended ones from Axminster Tools. ( £5.18 inc. VAT)

The alloy mounting brackets or cleats are an excellent fit to the the box beam section which just 'snick' fits onto them with no play. I have mounted them onto some strong plywood which I hold in my woodworking vice until I can find a permanent mounting place. Four heavy duty lag bolts are included in the kit to mount a wooden mounting board to a suitable wall space.

Some may notice that I have not mentioned the sliding cam-lock. Well the reason is the existing one works well enough but a redesigned and improved version will soon be shipped so I will review that. Note that current RB owners will have the option of a replacement.

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