Looking for an Electric Jack-Hammer

[Michael GilliganParticipant @michaelgilligan61133]

[ UPDATE ]

I have ordered it, using PayPal … process couldn’t have been easier

Was it the right decision ?

… only time will tell.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Nigel Graham 2 on 28/06/2023 21:15:08:

They were never called "jack hammers" in the UK! That's a US-ism.

I think a true "jack-hammer" is a mining tool, fitted with a screw-jack or air-ram to feed it into the shot-hole it is drilling.

The tool used for digging up roads and demolition is more often called a "road breaker", or if air-powered, a "pneumatic drill".

Small work now is usually done with an SDS drill with hammer action.

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Thanks, Nigel

But honestly, I don’t really care

A rose is still a rose and all that

It was a suitable title for the thread, and I explained what I wanted.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

PostScript for Nigel:

You may be interested to read my post, times-stamped 20/07/2016 11:52:16

on this old thread: **LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=113570&p=54

… and particularly Jason’s correction.

MichaelG.

[John Doe 2Participant @johndoe2]

Posted by Michael Gilligan on 28/06/2023 14:48:28

This chap is much younger, and much beefier than me !!

That chap might be beefy but he is wearing NO safety gear. No ear defenders, no safety glasses, no gloves, shorts, and I would be very surprised if those are steel toe cap and soled trainers. Oh, and the electrical extension is not completely unrolled.

I had some similar lads with similar equipment break up my old concrete kitchen floor, years ago, also with NO safety gear. When I offered them some ear defenders they looked at me as if I was mad. Don't they teach people anything these days?

Edited By John Doe 2 on 28/06/2023 23:42:42

[Michael GilliganParticipant @michaelgilligan61133]

Posted by John Doe 2 on 28/06/2023 23:40:34:

That chap might be beefy but he is wearing NO safety gear. No ear defenders, no safety glasses, no gloves, shorts, and I would be very surprised if those are steel toe cap and soled trainers. Oh, and the electrical extension is not completely unrolled.

I had some similar lads with similar equipment break up my old concrete kitchen floor, years ago, also with NO safety gear. When I offered them some ear defenders they looked at me as if I was mad. Don't they teach people anything these days?

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All reasonable comments, John … although not strictly relevant to my question

You may get an added frisson from knowing that they borrowed the extension lead from me.

I have ordered whatever it is I have ordered, so I am quite happy for this thread to evolve.

MichaelG.

[Pete RimmerParticipant @peterimmer30576]

Posted by DC31k on 28/06/2023 17:57:34:

Posted by Michael Gilligan on 28/06/2023 16:51:22:

They only appear to do 240V so my safety-conscious approach is probably doomed.

The UK's use of 110v on building sites is part historical curiousity, part institutional conservatism. Before the days of RCDs, 110v (centre tapped to earth) was a good way of preventing people getting killed. Now that RCD technology is mature, the rationale for having low voltage stuff is less clear.

IMO they will never swap out 110v centre-tapped earth for 240V RCD protected site tools, and it wouldn't make sense to for several reasons:

1. Most small tools which would traditionally be run on extension leads are now battery operated. Some main contrctors actually require it.

2. Where you have a transformer right now with 6 or 8 outlets on it you might only get four (expensive) RCD-protected ones.

3. Building sites by their very nature are exposed to the elements. Running 240V leads all over with RCD protection is just a recipe for nuisance-tripping which costs production and if it's the supply that's faulty it'll cost the site standing time.

4. The incidence of injury from 110v power by electrocution is very, very low. Why would they change it especially when everyone already has the equipment?

[Michael GilliganParticipant @michaelgilligan61133]

Here’s an interesting snippet from Excel’s Handling Instructions:

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As the very satisfied user of a three-wire pacemaker, I know that attempting to obtain anything other than ‘broad-brush’ advice on such matters is futile.

The likelihood of this particular electric motor interfering with my device does seem trivially small, and I have to wonder how its field strength compares with that on an Electric ‘Bus [public transport].

MichaelG.

Edited By Michael Gilligan on 29/06/2023 06:53:30

[PeroParticipant @pero]

Hi Michael

When I purchased my present house some decades ago I found I had need for a small jack hammer to carry out a number of smallish jobs over an extended period.

Like you I found that purchase was more cost effective than hiring.

With this in mind I purchased a small Hitachi brand tool which proved very suitable. I could fairly comfortably handle the weight ( important safety aspect ) and although I did initially suffer with a bad back due to bending I was later able to find longer tools ( chisels ) which helped alleviate this problem.

I think it has paid its way and is still available whenever I have the need.

One other thought. When breaking up paving I often use a long pry bar to slightly lift the edge of the paving before hitting it with a 7 lb sledge hammer. I find this breaks the paving quite readily and is actually faster and less messy than using the jack hammer. Works fine on paths etc but could be less successful on a 100 mm floor slab. I mention a 7 lb sledge as I lack the strength to wield a 10 lb version.

Stronger ME's may find larger tools more effective but I have found mine will do anything I require around the house.

The EXCEL model, as shown in the post above, looks like it should do the job.

Pero

[Michael GilliganParticipant @michaelgilligan61133]

Thanks, Pero

MichaelG.

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Just as an aside … I have an Hitachi reciprocating saw which is giving excellent service.

[Michael GilliganParticipant @michaelgilligan61133]

An encouragingly hefty package was delivered by DPD a few minutes ago.

MichaelG.

[Trevor Drabble 1Participant @trevordrabble1]

[Michael GilliganParticipant @michaelgilligan61133]

On opening the carton, first impressions were excellent; a blow-moulded case, with wheels !

Unfortunately, this is obviously not up to the job … one of the catches doesn’t work, because the plastic has split in transport.

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I have written to the supplier, in the hope that they can send a replacement case.

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Weather permitting, I might test the beast late this afternoon.

Very glad I didn’t buy anything considerably heavier than this machine’s 19.8 kg

MichaelG.

[John OlsenParticipant @johnolsen79199]

I didn't know that you Brits used 110 Volts on building sites. The idea intrigues me since in fact 110 Volts is not actually a lot safer than 230 Volts. Both are quite capable of delivering a lethal current through your heart, especially if your skin is damp or sweaty, as it might well be on a building site. There are 400 deaths and 4000 injuries each year in the USA for instance. 230 Volts might be a bit more likely to kill you but I would not risk my life on the difference.

What we did in NZ, which I would not claim as perfect either, is that you are supposed to use an isolating transformer. This gives you a secondary which is not earthed, so that it takes two faults rather than one to create a dangerous situation. Eg one side has to be accidentally grounded while the other side touches you, or you have to be touching both connections. But that meant a bulky transformer for every tool, so in their kindness they allowed the transformer to have two outlets. That of course doubles the chance that one of them is faulty. I prefer RCD's myself, especially since it is so easy to check them, Battery tools are also good.

John

[Michael GilliganParticipant @michaelgilligan61133]

John

The ‘Yellow Transformer’ actually delivers 55-0-55 which is, I believe, considered ‘intrinsically safe’

MichaelG.

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Ref. [one of many]

https://cmdonline.co.uk/products/110v-site-transformers-yellow-portable-transformers-1kva-to-5kva

Edited By Michael Gilligan on 01/07/2023 06:30:49

[DiogenesIIParticipant @diogenesii]

Just out of curiosity, how 'workmanlike' is the cable and strain relief?

[Pete RimmerParticipant @peterimmer30576]

Yes as Michael says above the 110v tools are powered from a centre-tapped-earth isolating transformer which means that the maximum potential is actually 55v RMS.

You could get a lethal shock from it, probably, if you're working around sea water. I know that I've had a few tasty ones when the tools have got salt water in them when doing marine work. Many modern small tools have smart triggers which the salt water plays havoc with. One job I did (cutting the sea walll opening for the new tyne tunnel) we had to keep a barrel of tap water handy to jetwash the gear through at the end of every day then leave it in the drying room to dry out for the next shift.

[Michael GilliganParticipant @michaelgilligan61133]

At 20 minutes duration, this is probably unnecessarily long … but it’s a good introduction to the yellow stuff:

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MichaelG.

[Robert Atkinson 2Participant @robertatkinson2]

The US domestic electrical supply is very similar to the UK 110V tool system. It is twice the voltage of the UK safety sytem. Domestic premises in the USA are typicall provied with a split phase 115V – Neutral – 115V with the neutral connected to ground. The two 115V supplies are 180 degrees out of phase so there is 230V between them. Heavy loads such as water heaters, air conditioning and washing machines are 230V and connect across the two phases.

Robert.

[Michael GilliganParticipant @michaelgilligan61133]

A quick review, whilst I am having a breather !!

The machine performs superbly, and was ridiculously good value for money.

So far, the limitation is very obviously my own pathetic inability to handle the weight with any finesse.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

[ POSTSCRIPT ]

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”Oh deary-me, that’s a little inconvenient” said I … or words to that effect !

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Yesterday, I decided to remove another of the old steel fence-posts, and positioned the chisel point about 30mm away from the post, hoping to free it with minimal disturbance to the concrete slab.

… a couple of seconds later, it found the path of least resistance:

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Those ‘familiar with the art’ will immediately notice the problem !

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Two hours later, I finally managed to cut and peel-away enough of the steel to release its grip on the chisel.

Several lessons learned.

MichaelG.

[Ady1Participant @ady1]

The gods laff at us

These things only happen to those of us who make the effort…

An angle grinder would free that in a couple of minutes, 1mm stainless wheel

[Michael GilliganParticipant @michaelgilligan61133]

Unfortunately:

• my stock of angle grinder disks went AWOL in the relocation to Wales
• access to the relevant cutting line was near-impossible

I ended-up using the Hitachi reciprocating saw [blunting two Starrett bi-metal blades in the process] and then had to use a 3/8” square file to make the final cut … it made a satisfying ‘crack’ as the tension released, but I still had to prise-away the metal with a crow-bar before I could pull the machine free.

MichaelG.

[Author]

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