Wednesday, 7 June 2017

Digital radio, LED lights and an external antenna

The general lighting in my shop is very good. However I did notice that there were dark spots particularly at my assembly table and bandsaw. I looked at the new LED lighting strips meant to replace standard fluorescent strips but in the area I wanted to increase lighting levels strips would not be practical.

I then looked at RO80 lamps and they suited the area. I bought 10 E27 bases and fixed 5 of them in place. One per roof joist over the assembly table and one behind the bandsaw and one in front of the bandsaw.
E27 Lamp Holder

They were wired so that I could have a separate bathroom type pull switch for the two locations.
Bathroom Pull Switch

The LED lamps arrived and I screwed them in. These are cool white 5000K, 700 Lumens, 9W, 240 volt lamps. They have an E27 screw thread and have an equivalent lighting output of a 75W halogen lamp.

I switched them on an the difference was very noticeable. I could now see what I was assembling!
The augmentation of lighting around the bandsaw was also very good.

Lighting above the assembly table

Lighting fore and aft of the bandsaw

5 additional LED lamps in situ.

Then came the bad news. The shop music system has a digital DAB/DAB+ radio receiver. This is the standard in the UK and some other parts of the world. It also has a conventional FM mode. The antenna for this was inside the shop. This is not an ideal situation as the roof is metal and cuts down the signal profoundly. When the new lights were switched off the reception on DAB and FM was just about acceptable. There were some stations that "burbled" as per DAB reception but that was ok to put up with.

When the LED lights were switched on the DAB reception was completely blocked. I put this down to the electronics in the lamps generating EMC (probably inducing it into the electricity supply wiring) and overloading the front end of the radio receiver. I switched over to FM and there was also noise on there and some stations could not be listened to especially in stereo.

I had a quick look on Amazon and found a supplier of external DAB compatible antennas. These were fairly cheap so I bought one.

When it arrived the antenna was assembled and clamped to a 10 foot long aluminium pole. DAB in the UK is vertically polarised so I positioned the folded dipole in a vertical orientation.
The outside of the shop already had a suitable antenna bracket fitted to the external wall so I simply mounted the pole into this. The 75 ohm cable was routed through the inside of the tube.

DAB Antenna vertically polarised mounted on the outside of the shop

Then a hole was drilled through the brick wall into the shop and the cable passed through. The hole was sealed with some external mastic sealant. Inside the shop the cable was routed up and along the walls, clipped into place and passed through into the shop music system. The cable was cut to length and the connector fitted. This was then connected to the radio receiver.

The receiver was powered up and the reception was clear and noise free. The LED lights were then powered up and there was absolutely zero interference and no noise. The new antenna worked fine and the LED lights work great.

Wednesday, 31 May 2017

Driveway gates - Part 7 - cladding

The western red cedar cladding was fitted next. This was premade tongue and groove cladding from a local commercial wood dealer. The only thing I had to do was fit the tongue into the groove I had milled in the stiles. It is crucial that a spacer of about 4mm is used when fitting each board to provide room for expansion/contraction. Each board was fitted with a series of stainless steel screws pilot drilled into the iroko.

Several coats of Sansin exterior weather seal was applied. This is a beautiful waterborne finish that build up a nice satin appearance with a deep colour after many coats. It can be applied with a foam brush or sprayed. I opted to use a foam brush.

Next all the hardware was fitted. 3 banded hinges, 3 shoot bolts, and a vertical drop bolt into each leaf. Fitting of the stays was left until final fitting on site.

The job was now completed. The old gates were sawn up and became firewood having served their purpose for the best part of 30 years

Driveway gates - part 6 - Drawbored and wedged M&T joints

I had used wedged mortise and tenon joints on a previous gate project. One of the problems I found with this technique is the wedges can have a tendency of pushing the joint apart unless you clamp the joints first of all. Once the glue has set there is no issue of course.
The width of these gates is slightly bigger than the capacity of my largest clamps. These clamps have the facility of joining two together.
First of all one of the clamp heads is removed totally from one of the clamps. The adjoining clamp requires its movable clamp head turning through 180 degrees. Then the two clamps are simply joined with a large nut and bolt.zz
The glue up using West Systems 105 and 205 epoxy.
Draw-bored and wedged tenons make for an immensely strong joint

Each one of the tenons has a 5 degree wedge removed from either side of its width. I made a template from 1/4" plywood with the correct angle.
I also used the same template to cut some 5 degree wedges from some 1/2" scrap iroko stock. There are a pair of wedges required for each mortise and tenon joint.

I decided to use the drawboring technique "recently rediscovered" by many woodworkers. If you don't know what this is then Marc Spagnuolo and Christopher Schwarz both describe the technique on their respective websites/blog.

Marc's is here
Chris's is here

I drilled a blind 10mm (3/8") hole 60mm (2. 3/8") from the face of each stile. After dry fitting the tenon into the mortise a bradpoint bit was used to transfer the centre of the hole to the tenon.
The tenon was disassembled and the centre point was then moved 1/16" closer to the shoulder. A 10mm hole was then drilled into the tenon.

A batch of 10mm x 40mm long dowels were sawn to length. Then a 15 degree bevel was sanded into one end of each using a disc sander.

Driveway gates - part 5 - Diagonal braces

The stiles and cross rails were dry assembled, squared and clamped up. The table saw mitre fence was set to 38 degrees and each one of the diagonals had one end cut to this angle.
Each one of the diagonals had to be marked to the length and angle that was subtended at the other end. They should have been all roughly the same but due to discrepancies in machining there are always slight differences.
The intersect with the mid rail  was marked onto the diagonal. This angle was transferred to the table saw mitre gauge using a sliding bevel. The cut was made by sneaking up to get a good match. Then the piece was dry fitted into place. The edges of the diagonal was transferred onto the mid rail. The diagonal between the mid rail and top rail was lined up with the pencil lines.
This same process was then used to cut its upper angle.

The decision had also been made early in the design to use floating tenons to anchor the ends of the diagonals to the crossmembers. This required cutting 10mm (3/8") slots into each piece using a router. If you have a Festool Domino XL then use that instead. I don't so used the router method.
My mortises were cut 25mm (1") deep and the slot length is 100mm (4"). I marked the start and end of each mortise onto the face of each diagonal and crossmember when they were dry fitted in place.

Balancing a heavy 1/2" router onto a 1" wide board is not easy so I ganged a piece of stock onto the side of each piece with clamps. This gives a wider bearing surface. I also used a shop made plexiglass base screwed onto the router to fill in the cutter void and increase its length.

Clamps at either end to create end stops.

The resulting mortises obviously have rounded ends. Loose tenons were made to be a hair shorter than 50mm (2") and each edge had a 1/4" routed radius to match the mortises.
The loose tenons were glued into each of the diagonals to aid assembly further on in the process.
Shop made loose tenons and the corresponding routed mortise in a diagonal brace