Kennedy Power Hacksaw - newest addition to the workshop

[jonny neate]

I think thats why people reverse the blade when the damper plays up less friction on the forward cutting stroke,seems to help.

I had an old kennedy 90 in real bad condition could not get the damper to work any sense, a lot of the problem is the piston does not stay parralell in the bore and is shaped like a flying saucer if that makes sense.  So it only has a small contact area with the bore.You can groove them and put an O ring on them that can help a bit. My lastest Kennedy 90 is amazing and has even got tho original tripod stand and the damper works perfect.
                                           Jonny Neate

[jonny neate]

Just thought i would say i use ep90 geer oil in my dash pot,Ive have also got a user manual for it .
                                                                                                                          Jonny Neate

[raynerd]

Jonny, I might use some of that oil then. I`m using slide ways oil because it is thick but it could be too thick?!

[jonny neate]

Hi , I have put some coppies of the Kennedy manuals on eBay .
                                                                                        Jonny

[mechman48]

Hi Chris
When I first saw your video on youtube about this saw I told mesel' 'must have one of those'..tried as I might I couldn't find one on t'internet,noting along the way that Kennedy's & Chas Wade(partners) had long gone out of business back in the 90's..no chance there then! had a look on fleabay couple of weeks ago & lo & behold 2 of them up for bids..put my bids in but they went haywire during the last couple of minutes..one of them ending up going for £173...! the other for more I think! needless to say I was pipped at the post more's the pity.
So on reconsidering my needs I thought it over & went to Machine M's vat free day last Thurs & bought myself a new metalworker 6" bandsaw for just over £40 more the kennedy's auction prices. It would have been nice to have one of these sat on my bench but 'cie la vie', at least I have a band saw to use.
Cheers
George

[DELBOY52]

Hi,
I have just managed to get my hands on a Kennedy 90 Power saw.  Mine has one of the MEM no-volt release switches, but there is no mechanism attached to it for turning the power off at the end of a cut.  Does anyone know how these switches operate?
Also, the Damper pot was completely bone dry, and looks as though it has been for quite a while. I will probably use an EP 90 oil, or similar, to start with, but what do others use, and what is used as a rubber gator over the pot.
And finally, what is the purpose of the slightly smaller bored hole behind the dash pot?

Many thanks,

[andyf]

NVR switches usually incorporate a relay. The start button is a momentary contact, pushbutton job. Pressing it sends current through the relay coil, closing the relay contacts to send power to the motor. There is a feedback from the downstream side of the relay contacts to the upstream side of the relay coil, so once the start button has been pressed and the contacts have closed, the relay holds itself on. To stop, there is either:

Chinese version: a stop button with a plastic bar sticking into the relay and bearing on the contacts, so pressing the stop button simply forces the contacts apart. That stops the motor, and also breaks the feedback so the relay coil goes dead and when the stop buton is released, the motor won't restart until the start button is pushed.

Higher quality version: same principle of operation, but the stop button operates a real switch (push-to-break) in the feedback circuit. If your NVR switch is like that (the only way to find out is to have a look inside the casing) then adding another switch in series with the stop switch will do what you want. This extra switch is positioned so it is opened when the saw frame has descended to "cut complete" level. As the relay coil takes very little current (<0.05A, generally), a microswitch will usually suffice.

Can't help with the oil, gaiter or mystery hole, I'm afraid.

Andy

[RussellT]

According to lathes.co.uk the later model hacksaws had NVR switches but it's not clear that they had any mechanism for an auto stop.  As Andy says it should be possible to add a microswitch to interrupt the current in the hold on coil - but it is likely to be at 240V so will need insulation /enclosure.  The earlier ones had a lever that turned off the switch on the end of the motor.

On my model 60 I used a rubber bellows that I had in the scrap box for a gaiter.  I think it was off a brake master cylinder - I turned a plastic disc to fill the hole at the small end and drilled 2 holes for the damper rod and screw.

I can't help with the mystery hole as I don't have a model 90.  Perhaps you could post a picture.

Russell

[9fingers]

The hole, which should be tapped, is for the screw-in Tee handle used for carrying the saw on site.

hth

Bob

[JerryNotts]

I've had a Kennedy 60 for about 25 years or more.
Mine is in as-built condition.  It has worked flawlessly over most of that time,

I think I can answer a couple of questions that have been asked here -
1. The dashpot piston should have a thin spring steel washer fitted on its lower side and held in place by a large headed screw screwed into the opposite side of the thread for the central rod. This screw is adjusted to allow the flow of oil into the holes in the piston and the opposing rod is tightened down against it to hold the screw in place. The 'L' shaped off-centre rod bears down on the washer and is used to adjust the flow of oil.
2. Mine has the NVR switch which is lifted  manually to the 'ON' position, a rod attached to the cutting rails and bent into another 'L' shape with a plastic end cover is adjusted to turn the switch to the 'OFF' position as the cutting arm falls. Being the usual MEM type lever action switch its action is best described as snappy and the adjustment has to done with care and locked.
 but then I moved home.
If anyone wants pictures please let me know.

Today I decided to give it it's first service and to remove the years of crud.
It has the rubber gaiter covering the top of the dashpot, as is shown in some of the diagrams. This had worked free from the dashpot surround and as it is a tight fit I cannot see how to re-fit it.
Has anyone had this problem? Or any advice.

JerryNotts

[Digger]

My Kennedy hacksaw machine is much modified, it's driven by a single phase  240 volt motor  with a built in reduction gear on the end, the  saw  itself is  driven by a 'V' belt, the  final speed being in the region of   80 strokes per minute,
I am a firm believer in any machine tool must be fitted with a no volt release starter, that if the power is interrupted it will not restart on it's own.

The original Kennedy had  a hoover motor, which had a switch on the end cover that was, by the use of a  bit of steel bar hinged and moved by the  saw  frame decending, flicked this switch to the off  position, thereby stopping the motor.

I wanted something better than this arrangement, when the frame of the saw is lifted  to put what you intend to cut in the vice,  a pivoted vertical bar rests on a stop on the fixed base,  to start the saw, a linkage is moved to pivot this  bar to allow the saw frame to decend, ( anyone who has a Kennedy will understand this).

As I did not want to  have mains power  going to any switch actuated by the frame of the saw when it completed it's cut, so I installed a microswitch with it's normally closed contacts, wired in series with the holding coil supply inside the no volt release  switch housing.

This micro switch is actuated by the  use of a  camera shutter  release cable held in a bracket directly under the saw fram latch bar, as the frame decends this latch bar pushes the camera shutter release which in turn opens the contacts of the micro switch, interuppting the power  to the holding coil of the no volt release switch. and the saw stops.
I have found this saw to be invaluable, for  the smaller jobs encountered in the workshop, as  time is  not an overiding factor, it really does not matter how long it takes to  make its  cut, I just set it going then do something else.

Digger

[Meldonmech]

Hi Digger
                  The motor switch on my Hoover motor caused a fire which completely burnt out my motor.  I replaced the motor and have been switching off at the wall socket, at the end of cuts.  I bought a no voltage release switch several years ago, but never got round to fitting it. I recently visited Maplins to look at micro switches, I did not make a purchase, because I not figured out a tripping method. I would be interested in seeing pictures of your arrangement. I do miss that facility off self stopping when the cut is finished.
                                                   Cheers David

[Digger]

Hi Digger
                  The motor switch on my Hoover motor caused a fire which completely burnt out my motor.  I replaced the motor and have been switching off at the wall socket, at the end of cuts.  I bought a no voltage release switch several years ago, but never got round to fitting it. I recently visited Maplins to look at micro switches, I did not make a purchase, because I not figured out a tripping method. I would be interested in seeing pictures of your arrangement. I do miss that facility off self stopping when the cut is finished.
                                                   Cheers David

Hi David

I have sent you a private message, I tried to up-load some photographs but for some reason was unable to do so.

Digger

[Meldonmech]

Hi Digger

                Many thanks for your swift reply, and the accompanying pictures, they were exactly what I required. Looks a powerful motor you have driving your saw, it will take a lot to stall it.

                                                                                            Good luck with your future projects.

                                                                                                                  Cheers David

[Digger]

Hi David

The motor is only 1/4 hp, but because of the reduction gear, the final output torque is quite high, on one occasion when the saw jammed up, the drive belt slipped, which I suppose is a good thing, the stand to which the Kennedy is fitted was I believe, once part of the line shafting bracketry from a textile mill, the whole thing is mounted on castors, so it can be trundelled away quite easily, it's a  very useful bit of kit.

Digger