Thursday 4 June 2020

Why Doesn't My Power Tool Startup?

When a power tool won't power up there are various causes of failure. but troubleshooting should be done in a methodical order, the main thing though is to check the obvious first!

Equipment Needed:


Some screwdrivers, flat and Phillips head
Continuity meter or multimeter to trace continuity from the plug to the motor.


A non-contact voltage detector (optional). These devices glow when the tip is held close to a live cable


https://dengarden.com/home-improvement/Using-a-Multimeter

Important !!!
Remember to avoid shock, disconnect the tool from the mains supply before troubleshooting!!!


Troubleshooting: 


 ● It may be obvious but ensure the socket outlet isn't faulty, try the tool in another outlet to see if it works.

● Check whether the overload circuit breaker if fitted on the tool has activated. This happens e.g. on a table saw when the motor is stalled. To reset you need to press a button. The breaker may need a couple of minutes to cool down before resetting

● If plug is rewireable check for loose screws at plug pin terminals, loose fuses etc. 




● A common cause of failure especially with drills and other hand held tools is one or more broken wires in the power flex caused by metal fatigue in the cable (like when you break a paper clip by bending it backwards and forwards) , this usually happens where the cord leaves the plug or where the cord enters the tool. If you have a non-contact voltage detector, you can use it to trace the break from the plug to the tool. Plug in the tool and hold the tip of the detector at the plug, it will glow here but as it is moved down along the flex it will stop glowing after the break (If the break is in the live core of the cable)

● Sometimes it is possible to detect where a break is in a flex by stretching it, the flex will narrow in the region of the break

● If you still can't trace the fault, unplug the tool. Open it. Check the continuity from each pin of the plug to the switch in the tool.

● A faulty on / off switch can prevent the tool from working. Use the continuity tester to check this

● Loose spade terminals on switches may cause intermittent operation

● Tools with green and red start and stop buttons may have a faulty relay

● The brushes in the motor may have worn down

● The armature or field coils of motor may have gone open circuit. The field coils can be checked with the continuity meter

Tuesday 19 May 2020

String Trimmer Line

This 0.095 inch diameter (2.4mm), 3 pound, 685 foot spool of professional trimming line manufactured by Oregon should last you years and years. It has a high strength inner core and an outer coating to prevent welding. In other words it is less likely to stick as it unwinds from the spool. The square edges also improve cutting efficiency compared to standard round profile type
Check your trimmer to see whether it is compatible with this diameter line.

Sunday 19 April 2020

Activities for Kids During the Covid-19 Lockdown: Sowing Seeds

Equipment

  • Some trays, pots, yogurt containers or similar
  • Spray bottle from shower or window cleaner
  • Seed compost or multipurpose seed and potting compost
  • Seeds

Time to sow

For annual and half-hardy annuals, February to April. Check the seed packet.

You can use any types of pots, boxes or proper seed trays

Steps

  1. Fill the containers almost to the top with seed compost
  2. Shake the seeds out onto your hand and scatter evenly over the compost
  3. Don't cover very small seeds. Seeds a few mm in diameter can be covered with a sprinkling of compost. Larger seeds such as sunflower seeds should be pushed about 1/2 inches (12mm) below the surface.
  4. Water with the spray bottle and keep the compost moist. Only water as needed, not everyday. You can use a watering can, but unless it has a fine sprinkler rose, it can flood the compost and wash away seedlings.
  5. Keep the tray in a warm place and cover with a sheet of card to conserve moisture and keep the seeds dark until germination
  6. Once the seeds germinate, remove the card and move to a bright place such as a window sill.
  7. Transplant into pots once seedlings have their first pair of "true leaves" (the second pair of leaves to appear). Once the plants become large enough, transfer to their final location.

Fill tray with compost

Sprinkle seeds from your hand
Transplant seedlings once they're big enough and have two "true" leaves

Wednesday 22 January 2020

Repairing a Heat Selection Knob on a Fan Heater

Well this was frustrating! The range selection knob on my fan heater was turning without doing anything. I decided to try and open the case to see what was wrong, but of course the manufacturer had used security fixings, relatively uncommon triangular ones too!



I have lots of shapes and sizes of Torx bits and screwdrivers, but they would be useless in this situation. Luckily I managed to undo two of four screws from the upper side of the heater using a large jeweler's screwdriver. This allowed me to pull the case apart just enough to remove the knob.


Part of the shaft of the knob had snapped off in the switch. Gluing, even with superglue wouldn't be a permanent fix because the resistance of the switch was such that a large torque was needed to change range.
First I removed the broken-off piece of shaft from the switch using a woodscrew. The piece was hollow as was the other piece of shaft remaining on the knob. I decided to attach the two pieces together using a rivet pin.


I hoard lots of scrap, and rivet pins are part of my collection, along with self tapping screws, springs, nuts, washers and all sorts of other miscellaneous items! Some of these pins were exactly the right diameter.

I dripped some super glue into the hollow interior of both sections and also on the broken surface, then joined the two pieces together. Some heat from another fan heater accelerated curing of the glue.


After trimming the pin, I replaced the switch, cost of repair? Zero!

Monday 20 May 2019

How Do I Mix Fuel for My String Trimmer, Hedge Trimmer or Chainsaw?

These garden power tools generally have a two stroke engine (also known as a two cycle or 2T engine), and to make them lighter, they don't carry motor oil on board as in the case of a lawn mower or road vehicle. Instead oil is added and mixed with the petrol (gas) before use.
In general petrol/oil ratio for 2-stroke engines is 40:1 or 50:1 which is 2.5% or 2% oil. 50:1 is equivalent to 20ml in 1 litre or just over 2 1/2 US fluid ounces per US gallon. 40:1 is equivalent to 25ml in 1 litre or 3.2 US fluid ounces per US gallon. 

After adding oil, swirl the contents around to ensure it's thoroughly mixed.Consult the manual of the machine for details of the recommended ratio.



Tuesday 12 March 2019

Homemade Tools - Snow Rake

I put this together from scrap 2 x 1 and 3/8" (10mm) plywood. I used some pieces of waste wire from electric cable (string would be just as good) as ties to stop the board pulling off the end of the 2 x 1.



Tuesday 5 March 2019

New Science Q&A Article for Children

Just published a new science guide for children.

"Top 100 Interesting Science Questions for Kids" covers space, nature, technology, engineering, elementary math, chemistry, physics and biology.




Sunday 24 February 2019

AA to C and D Battery Converters

These are useful little gadgets if you don't have any C or D cells to hand. AA cells are readily available in cheap packs from pound/dollar/euro shops and are probably also optimised to have a higher energy density.



Tuesday 19 February 2019

Snow Shovels by Briggs & Stratton

Think I'd prefer shovelling by hand to warm up, but these snow shovels by Briggs & Stratton could be useful!



Lidl Tools from the Centre Aisle - Air Wedges

Picked up this set of air wedges in Lidl . They're like a mini version of what firemen use. Handy for lifting and positioning stuff and pushing things apart.


Valves for Shutting Off Water in the Home

Just a reminder folks to identify where all your gate valves are for shutting off water in an emergency. Tie a label around them or write the function on the wall behind with a thick marker. Valves can and do seize, so it's good to exercise them at least once a year. You don't want to be running around like a headless chicken when there's a water leak.

Monday 18 February 2019

Cutting Down the Overgrown Sycamore


My shepherd's hook for pulling down the overgrown sycamore in the back garden. The plan was to cut low and reach high with the 20 foot hook to get leverage, without having to climb up to tie ropes.


The hook was made from a 6m length of 12mm rebar, with a loop at one end for hooking around limbs and a smaller loop at the other end for attaching a rope. Unlike a rope, the hook was rigid and could be extended high up into the crown, without having to do any climbing.




One 8" bough down, about 8 more to go. This one managed to land on a sheet of steel that sliced into it.



I decided to make a rope saw for cutting through some of the limbs that were nearly vertical. It would have been dangerous to cut these with a chainsaw while I was up the tree. Using a rope saw was slow and hard work but really safe because limbs could be cut remotely and pulled down using a long rope and my sheperd's hook. The saw was made from an old chain saw chain. I cut one of the links with an angle grinder and opened it out, then attached the ropes to rings passed through link holes in the ends of the chain.




Finally finished cutting!


Lots of logs to cut up.


I chipped all the branches. They can be used as fuel on a stove or as a mulch in the garden for suppressing weeds.


By winter last year after a warm summer, the tree had put on 6 feet of new growth. Looks as if I'll have to do more lopping this year!





Sharp Vintage Calculators

My favourite calculator, the Sharp EL506. Really simple to use and no fancy "natural entry" nonsense that slows everything down in modern versions, with lots of extra keypresses required to do simple calculations. Cost me £5 in '84 when I started college. Batteries then lasted over 20 years.

Wednesday 26 July 2017

"Talking Tools"

Just wanted to let you know about my new Facebook group "Talking Tools".
It's a platform for pros and newbies to talk about tools, share reviews and tips. Novices can ask questions and get help from more experienced members. Manufacturers can also show off their new products.

Talking Tools

https://www.facebook.com/groups/203863340138801/

Friday 24 March 2017

Lawn Mower Won't Start? - Top 10 Small Engine Troubleshooting Tips

  1. Use fresh petrol (gasoline). Old petrol can cause difficult starting. Make sure there is enough fuel in the tank and check the vent in the tank cap isn'tclogged
  2.  The spark lead should be firmly attached to the plug, and the plug tightly screwed into the engine block. Try replacing the plug with a new one if the engine won't start
  3. Most modern mowers have a control handle which needs to be pushed forwards/upwards and held in place to keep the engine running. Make sure this control is mower is held fully against the mower handle while starting.
  4. If a manual choke is fitted, turn it on. Don't turn on the choke if the engine has been running in the last 10 minutes
  5. If the engine has a primer bulb, press it about 5 times. If the mower runs out of petrol during cutting, it will need to be primed again
  6. Check the air filter isn't dirty. Wash and dry foam type air filters in warm,soapy water. A paper filter can be blown out with an air compressor, but will eventually need to be replaced
  7. Check the cable connecting the "dead man's handle" (the control which keeps the engine running when held in place) to the engine is not damaged or snapped
  8. The carburettor should be tightly screwed or bolted to the engine
  9. Make sure there isn't any water collected at the bottom of the petrol tank. If there is, drain the tank and use a piece of stick or long screwdriver with a piece of rag tied on (with a twisty tie) to soak up water
  10. If the starter cord is hard to pull, check the underside of the deck and remove any clumps of grass which may be jamming the blade. Disconnect the spark lead before attempting to move the blade to remove clippings!
    Paper air filter

    Foam air filter