Kennedy Hexacut machine hacksaw

[Graham MeekParticipant @grahammeek88282]

A few days ago I promised that I would post a few photographs of the conversion.

The next photograph shows the new ribbed pulley. Which is all that is required to be made to convert this machine.

Lastly the saw in action, if you notice from the the blurr on the hacksaw frame this is taken with the saw in motion.

The material is 40 mm Aluminium and the saw cut through this in several minutes.

You might also notice the Brass swarf from the previous cuts this morning.

Regards

Gray,

[Leo F Byrne 1Participant @leofbyrne1]

I think I’ll do this. What length belt and where did you get it? I can turn up a new pulley in aluminium.
You should be ashamed of the brass swarf – but don’t worry too much. I’ll post pics of the area under MY saw!

[Graham MeekParticipant @grahammeek88282]

Hi Leo,

My apologies for not getting back to you sooner. I seem to have had computer problems this end.

The belt Ref No. is 559P/220J _10 RIBS. I purchased my belt form Simply Bearings, (Usual disclaimer), it was here with in two days.

I am going to send you an PM with my email address so that you can have the PDF drawing of the pulley.

Regards

Gray,

[ianjParticipant @ians]

I have a Kennedy model "90" hacksaw, which is much larger than the "60" (Hex bars are 21mm AF)

I've never managed to get the flat belt to run on the centre of the large pulley.

So seeing Graham's Poly belt conversion I decided to do the same to mine.

Been a larger machine the dimensions are different to Graham's.

Large pulley diam. 9.875" (251mm)

Small pulley diam. .96" (24.38mm)

Centre distance of pulleys 6.8125" ( 173mm)

Graham very kindly calculated the Poly belt length as 34" ( 864mm)

This was purchased from "Simply Bearings" Part No. 864PJ/340J-14Rib

As can be seen in the photo the belt now runs nicely on the centre of the large pulley and is far easier to put on than the old flat belt.

[BazParticipant @baz89810]

Graham you have a PM.

[Graham MeekParticipant @grahammeek88282]

A while ago I noticed on Ian’s 90 Saw above that there is a blade tensioning facility. While I have not as yet checked to see if this was standard on the 90. I thought the blade on the 60 would probably give a better finish if it was under some form of Tension. Plus it may even lead to extending the life of the blade.

Using a similar arrangement as the 90 was not really possible as the blades for the 60 are cut into two. The standard hole in the hacksaw blade would only work for one end of the hacksaw, (NB, tooth direction on the blade). Duplicating any such adjustment was deemed too much of an overkill.

I tried compressing the frame of the 60 using a Record 12″ “G”-clamp. The amount of effort required was negligible and the resultant cut surface did not show the previous striations of the previous set-up and was generally much better. The saw blade would ring slightly as it was cutting, so it was under tension.

While I could of continued to use the “G”-clamp the set-up. The size of the clamp pad faces made extracting the old blade and inserting the new one time consuming. Something simpler was needed.

The above shot shows the finished design in-situ. It will be noticed that the blade can easily be removed as the clamp does not go high enough to cause a problem.

(Please ignore the Brass thumbscrew, the Camera, or the Operator were having difficulty getting the focus right)

In use the 4mm Allen key in the M8 grubscrew is very easy to turn, due to the ball bearing at the bottom of the hole in the clamp pad. There is an added bonus in that when the adjuster is put onto the machine and slightly “nipped-up”. Before releasing the clamp screws on the blade to remove the old blade. This setting will not interfere with the original blade setting. Thus once the optimum setting is found, (This I found was about a 1/4 to 1/3 of a turn from the free state), this initial setting will remain for ever and a day.

Regards

Gray,

[Clive FosterParticipant @clivefoster55965]

Nicely done Graham.

Which reminds me that over 40 years ago when I first encountered a Hexacut saw I was told to push moderately hard on the end of the bow to put an “unspecified” amount of tension on the blade before tightening the second clamp as it would last much longer than if simply installed loose. Which was true.

But your little device is vastly better than shove’n hope.

Hafta say I was most impressed by the way the little, clearly made down to a price, beast coped under the conditions of casual carelessness with which it was used.

Clive

[Graham MeekParticipant @grahammeek88282]

Thanks Clive, It is nice to know I am on the right track.

I thought other Kennedy owners might want to make this little item, so I have loaded the drawing below. Having this here will save the un-needed exchange of PM’s and emails. The manufacture of this device took hours rather than days, so will no doubt repay its construction equally as quick.

 

Regards

Gray,

 

 

 

[Dave WoottonParticipant @davewootton]

Thank you for posting that Gray, I bought a very used one of these a while ago from the Facebook marketplace and am looking forward to giving it a good overhaul. The previous owner had attempted some fairly desultory repairs and fitted a new flat belt, and posted his efforts on Youtube, however none of the bodges are undoable, and the machine is fairly sound, so hopefully given a little time to get round to it it should be returned to full vigour. I had been thinking of some form of blade tensioning device, this is simple and doubtless effective, far better than my overcomplicated musings, I had not thought of a seperate tool for tensioning using the existing blade clamps, very clever.

Thanks again for sharing

Dave

[William AyerstParticipant @williamayerst55662]

Good morning all – apologies for the thread necromancy on this one – but some years ago I bought a Kennedy Hexacut sight unseen and while usable it came to me with a few problems and I was hoping to seek some help from the kind folk here to get it back in tip-top shape:

1. There is no belt guard – would it be at all possible for someone to provide some outline dimensions of the belt guard so I might fabricate one please?

2. The cuts are not square – drifting left when viewed from the front of the machine. I gather this may be due to worn bushings. If that is the case, am I best to replace bearings with Oilite or plain Phosphor bronze?

3. The auto-stop lever has broken – An extended stud on the Hoover motor has a nut on it, to which a bent piece of rod has been soldered. I think this may be after-market, as it doesn’t quite match any expected dimensions and the solder joint has broken (and been repaired) – I have thought about making a new one, with a silver-soldered boss for pivoting. Does anyone have the original dimensions of the auto-stop lever please?

4. The belt is in bad condition and not centred on the motor shaft, which is just domed over – I understand I can buy a straight replacement for it (540mm x 25mm flat belt – bearing boys) or a ribbed version as discussed in this thread (559P/220J _10 RIBS – simply bearings) – should I expect to bush the motor shaft with a pulley to bring things back in line? There doesn’t appear to be enough lateral adjustment.

[Howard LewisParticipant @howardlewis46836]

Normally, a flat belt will self centre when running over a slightly domed pulley.

Why? I cannot recall the proof shown MANY years ago at Technical College.

Possibly, a ribbed belt might behave in similar fashion

Howard

[Howard Lewis]

On Howard Lewis Said:

Normally, a flat belt will self centre when running over a slightly domed pulley.

Why? I cannot recall the proof shown MANY years ago at Technical College.

Possibly, a ribbed belt might behave in similar fashion

Howard

Nicely demonstrated here, Howard:

https://youtu.be/6sM0Qjumyro

https://woodgears.ca/bandsaw/crowned_pulleys.html

 

MichaelG.

.

 

[William Ayerst]

On William Ayerst Said:

Good morning all – apologies for the thread necromancy on this one – but some years ago I bought a Kennedy Hexacut sight unseen and while usable it came to me with a few problems and I was hoping to seek some help from the kind folk here to get it back in tip-top shape:

1. There is no belt guard – would it be at all possible for someone to provide some outline dimensions of the belt guard so I might fabricate one please?

2. The cuts are not square – drifting left when viewed from the front of the machine. I gather this may be due to worn bushings. If that is the case, am I best to replace bearings with Oilite or plain Phosphor bronze?

3. The auto-stop lever has broken – An extended stud on the Hoover motor has a nut on it, to which a bent piece of rod has been soldered. I think this may be after-market, as it doesn’t quite match any expected dimensions and the solder joint has broken (and been repaired) – I have thought about making a new one, with a silver-soldered boss for pivoting. Does anyone have the original dimensions of the auto-stop lever please?

4. The belt is in bad condition and not centred on the motor shaft, which is just domed over – I understand I can buy a straight replacement for it (540mm x 25mm flat belt – bearing boys) or a ribbed version as discussed in this thread (559P/220J _10 RIBS – simply bearings) – should I expect to bush the motor shaft with a pulley to bring things back in line? There doesn’t appear to be enough lateral adjustment.

The ribbed belt needs its own motor pulley and it needs far less tension to work. This pays dividends as regards the life of the original Phos Bronze bearings.

These bearings are cast into the parts of the machine. It is not a simple case of pressing the old ones out and pressing in new ones. They will need to be machined out. something I have to get around to on my machine one day.

The “cutting off to the left” is most probably as you have assumed a result of worn bearings.

Regards

Gray,

[Graham Meek]

On Graham Meek Said:

The ribbed belt needs its own motor pulley and it needs far less tension to work. This pays dividends as regards the life of the original Phos Bronze bearings.

These bearings are cast into the parts of the machine. It is not a simple case of pressing the old ones out and pressing in new ones. They will need to be machined out. something I have to get around to on my machine one day.

The “cutting off to the left” is most probably as you have assumed a result of worn bearings.

Regards

Gray,

Thanks Graham – it’s not the end of the world, I’m never doing precision work on it anyway, just using it to hack through big chunks of steel or CI I don’t want to expend the sweat on – but it would be nice to get it back into shape.

 

With regard to the pulley/ribs – I know I’ll need a new one for a ribbed belt, but I’m more just a bit confused as to what mine is doing. It would appear that it’s a sleeve on the motor spindle that has been rounded over, but has been slightly misaligned to pull the flat belt off the centre of the drive pulley?

Is it worth trying to lever off that sleeve on the motor spindle? Would you please be able to PM/Email me your plans for the 10-rib motor pulley on the chance I can get it off?

The bushings sound like a pain to replace – do you have any tips please?

[Graham MeekParticipant @grahammeek88282]

Hi William,

The original pulley on my machine was slightly larger than that shown on your machine. It had an Allen grub screw into the keyway of the motor shaft. If my memory serves me correctly it was also slightly “Crowned”. Whether this was an original fitting or not I cannot say. I suspect the belt tracking problem has been a perennial problem for the previous and countless owners.

I would get a can of “Plus Gas” to spray the pulley with before I attempted to remove it, or if you have some Diesel handy this will do. Failing that a Dremel type tool with a slitting wheel and cut down the keyway slot.

Now I no longer have my Emco FB2 machining out the existing bushes is not going to be easy. I was thinking about this earlier this morning and it looks like I need to make some form of line boring machine.

The correct oil for the dashpot is stocked by Morris Lubricants and I will need to sort the name out. I do know it is used in the steering box of a VW, Transporter I think.

Give me a day or two and I will post the Drawing for the pulley on here. It is on my old computer and I need to convert it from AutoCad to Jpg.

Regards

Gray,

 

[vic neweyParticipant @vicnewey60017]

The big spring that helps pull down the arm is also important, too strong and it will jam the blade

[Graham MeekParticipant @grahammeek88282]

Luckily I remembered I sent another Forum member a PDF of the pulley. Fortunately it was in the files of my current computer.

The oil is Morris Golden Film AG 140, Non-EP. This according to Morris’s Technical Dept is the equivalent to the Kennedy specification, which I sent them at the time.

I have found this oil gives quite a range of adjustment on the dashpot.

Regards

Gray.

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