Lets Talk 6X4 Bandsaws !

[BaronJ]

Hi Guys,

I promised that I would do a write up on some of the modifications that I did on my Taiwanese 6X4 bandsaw that I acquired from an engineering company that I've done work for and they let me go and raid their scrap box.

The bandsaw was hidden away in a remote store room, having been discarded as no good ! In actual fact at some time in its life it had fallen on its back, breaking the hinge pivot arm, to which someone had tried, badly, to do a plate repair. The machine also had a 1 Hp Brooks motor fitted. Presumably because the original motor had either failed or been damaged when the machine fell over.

The three pictures below show the original broken hinge pivot. I obtained a new one from "Machine Mart" here in the UK, I also purchased a new gearbox pulley from them. A very reasonable £12 pounds inc carriage and VAT for both items.

Here you can see the bodged repair. The blade arm wobbled all over the place, no hope of a square cut !

Screws were put in the sides to attempt to strengthen the repair.

The new hinge pivot arm before being painted.

The bandsaw was on a tinplate stand that had seen better days !

I didn't take any pictures of the machine when I got it, however I did take a lot during the complete refurbishment.

I designed and built a new square tubular frame stand for it including putting it on 75 mm swivel castors, two of them having a braking mechanism. Which is handy to stop it wandering off in use.

The steel that I used was 1" square 10 gauge wall thickness. I used offcuts of the square tube for the original support bolt placement going through the cast iron bandsaw frame.

I used some pieces of scrap 3 mm steel plate with slotted holes just in case I hadn't quite got the holes in the right place. In fact it was a good thing because the holes in the casters were a slightly different spacing for the ones without brakes.

 

[BaronJ]

Next part:

One of the things that needed fixing was the motor mounting plate ! Again basically a bit of bent tin which simply didn't fit the motor mountings properly.

As can be seen here placed on top of the piece of 3 mm steel plate that I used to replace it. As can be seen it is a little bit larger in size in order to accommodate the Brooks motor's larger frame size.

This is the new motor mounting plate with the holes drilled and threaded M8 to match the Brooks motor mountings.

A picture of the Brooks motor before being painted.

This is the bandsaw body being set up on my Chinese copy of an Optimum BF20LB mill, ready for milling the slot on the far side.

This is the slot before being milled, you can see the cut in the bottom where the bandsaw blade has cut into it. The original sides of this slot are tapered inwards, so I milled the sides square so that I could fit a solid piece of steel in there.

This is how it looks after milling and fitting the blanking piece. It is simply pressed in place with a coating of super glue ! I was going to use Locktite but didn't have any to hand at that point in time.

The finished and painted bandsaw body ready to fit onto the new stand.

 

[BaronJ]

Part three:

When it came to re-assembling the blade arm I discovered that the support guides for the blade tensioning wheel were very sloppy ! In fact the guides were made using 4 mm thick material running in a 5.5 mm slot. I replaced them with skimmed down 6 mm plate.

These two pictures are of the original guide plates resting in the slots intended to support the blade tensioning wheel.

This picture is of the new guide plates that I made to replace them.
Now the wheel is held square without any side to side wobble and the blade tracking mechanism works properly.

It you look carefully you can see that the gap is a fraction wider at the bottom than where the wheel spindle is ! This is because the tracking is set by a screw pushing the block holding the wheel spindle away from the mounting, relying on the blade tension to pull it back. In this way the blade is caused to track on the wheels properly.

I'll cover some of the other modifications later ! Its dinner time for me now.

 

[BaronJ]

Part four:

Following on from the last post,

These are the new plates drilled and ready to fit, replacing the ones shown laying on the frame above.

This picture shows the new plates fitted and now supporting the tension wheel spindle.

Another very useful modification ! Replacing the hex head bolts holding the blade guides with hex cap screws and a new thick washer. Originally the fastenings were hard to get to tighten properly when setting the blade square.

I had to file a little off the sides in order to get enough twist to set the blade dead vertical. I also has to file the face under the new thick washers flat, there were casting marks on the face causing the washers to **** to one side or the other. This simple change makes setting the blade much easier.

Also in this picture you can see another modification that I made to the vise and one that I made to the arm stop.

The arm stop has a small loose block sat on top ! The idea being to prevent the blade resting on the added piece when not in use. This has since been replaced with a hollow cap because I kept knocking it off.

One of the other useful things is extended vise jaws. Not only do they allow me to cut thin pieces but also allow me to clamp material between the jaws on top of them. This improves the cutting of wide flat plate by increasing the blade cutting angle.

I also added a threaded hole for a screw which saves me having to look for a packing piece of the right size when cutting short or thin pieces.

I drilled the vise plates and used M6 hex socket countersunk screws to fasten the new extension plates to the vise jaws.

More later:

 

[goldstar31]

I agree with the us eful extension and added a long bolt at the rear to keep things parallrl ehen cutting short lenths.
Very Low tech but it works

 

[BaronJ]

Hi Guys,

Part five:

I found the drawing that I did for the stand !

You will need to enlarge the picture to be able to see the dimensions, for some reason they have become very small but are fine on the DFX drawing.

This is the screw that I made for the jaw spacer. It is simply a short length of M8 threaded rod with a knurled aluminum knob Locktited to one end.

During the refurbishment I measured the amount of run out of both pulleys and only found that there was a thou on them both. A quick clean with de-greaser was all that was needed to clean the blade track.

This is the new motor mounting plate after painting and having decent hinges made and fitted.

One side effect that I found after making a hydraulic drop damper was the counter balance ! The weight of the motor and the fact that it is mounted slightly further back almost perfectly balances the blade arm weight with only a light loading applied from the spring adjustment screw. In fact without the spring attached there is only 14 Ibs of dead weight measured under the blade.

This is the almost finished bandsaw fully painted and ready for action.

I had to buy a new "A" section belt for the saw because the motor is further back, but there is absolutely no hint of any risk of it falling on its back as it would on the original stand.

A close up without the arm cover fitted giving a better view of the new blade guide bearings and pivot arm hinge. Notice the white plastic spacer on the right side of the hinge. I found that the blade arm could drift from one side to the other, so I made a spacer using "Nylon 60" plastic to prevent that. This also means that I can now get consistent length cuts when using the length stop.

I also spent a good deal of time not only ensuring the the blade cuts as square in both planes as I can make it, but I also made sure that the vise is square to the blade as well. I can now cut within a few thou of dead square without requiring a clean up of the material being cut.

Well its been a long post but I think that is about it ! I do have many other pictures and I'm happy to post them if anybody wants to see a particular feature. Comments welcome.

Thanks for looking !

 

[bazmak]

Just seen this thread and really enjoyed going thru it.Congratulations on a great job well done
This is the work i love doing.Getting a broken down item for next to nothing and bringing it back to life
especially if its something you need and will use.Does it have a talble for the vertical position ?

 

[goldstar31]

Hi John( et al)

Digressing somewhat, I have never found a saisfactory method of holding down those large, round sort endes of metal. Perhaps you or other readers might provide information thatI certainly do not posses.

Expanding the topc, I am wanting to change the rotating workhead from a sinle graduated casting to the newer TWO bits of Mild Steel. I was able to obtain a short bit of 'round; but have to split it into two bits.

Therwise, it means making a special 'circulsr dovetail cut around the perfery of the block and it requires a rather awkward cutting tool.

I CAN do it, it follows the words and music of the Model Engineer's Workshop Manual description by Geo Thomas of how he constructed his small ungeared rotary table.
That machining is where the tool and cutter grinder such as the Stent and the Quorn possess 'certain advantages' which other lesser tools do not possess.

Worried Blue Eyes

 

[timo_gross]

Hello Norman,

not exactly sure what your problem is. You want to cut a disc into two discs? I just made this mock up setup. (not my idea saw it somewhere).

Put some square block, in this case my angle plate in the clamp of the machine.
Then use a C-clamp to clamp the disc onto the angle plate.
You will have to rotate the part a few times.
Then cut however deep you can go without cutting into the clamp. Avoid clamping the gap, packing or leaving enough material in the middle.

Greetings Timo

 

[timo_gross]

I just remembered where I saw it. The lady explains it worth watching in my opinion. 14:30 the clamping starts.



Cheers Timo

 

[timo_gross]

Hi Guys,


Here you can see the bodged repair. The blade arm wobbled all over the place, no hope of a square cut !

View attachment 126465
Screws were put in the sides to attempt to strengthen the repair.

View attachment 126470
The new hinge pivot arm before being painted.
....

Seems you had good luck that you could find this spare part (very cheap) If it would be a car, you would have spent that much just for the parts number . I wonder would it have been possible to solder the fracture? (not for 12 obvoiusly)
Would you have manufactured a new part otherwise?

Greetings Timo

 

[goldstar31]

Timo
Thank you for your replies.

Might I respectfully comment that that the Rotary table' video is not applicable. I have and have made numerous rotary tables and all that I expressed was where the technique for the eventual \workhead' on my old Quorn and rthe new Mk3- still as a kit. You have consequuently 'missed the point.
I have what , conceivavb;y be regarded as 'rotary tables' are on my Stent and in Mark1 Form already pn the Quorn and my Deckel SO close has the built in facility.
So let me return to the Problem which I eaised.

Like BaronJ, I have a Typical 'Raiwanese' 6. x4 metal cutting saw and you are again decr ibing YOUR solution to your problrm but -- NOT mine and actually for what must be thousands of iother users.
The fixed casting which normally holds materials in a vise/vice does NOT extend- to hold anything away from the vice itself.

I and the thousands of other 6 x 4 users want a solution which applies to their machine-- and noyt anyone elses;s.
Therefore I look forward to what might be the answer to my problem.

Speaking again, getting two bits of metal to do the job is simple and cheap. Cutting two bits of round metal does NOT require changing a machine to do it.
I can only apologise if my comments might be somewhat offensoive but I actually gave John Baron a part complete set of Mk1 castings beause I had and still have no use for them nor find the machined onne on my working Quorn suitable to my future requirements.
So My apologies if there if difficulties between us might cause disagreement ot inded friction.

 

[timo_gross]

Timo
Thank you for your replies.

Might I respectfully comment that that the Rotary table' video is not applicable. I have and have made numerous rotary tables and all that I expressed was where the technique for the eventual \workhead' on my old Quorn and rthe new Mk3- still as a kit. You have consequuently 'missed the point.
I have what , conceivavb;y be regarded as 'rotary tables' are on my Stent and in Mark1 Form already pn the Quorn and my Deckel SO close has the built in facility.
So let me return to the Problem which I eaised.

Like BaronJ, I have a Typical 'Raiwanese' 6. x4 metal cutting saw and you are again decr ibing YOUR solution to your problrm but -- NOT mine and actually for what must be thousands of iother users.
The fixed casting which normally holds materials in a vise/vice does NOT extend- to hold anything away from the vice itself.

I and the thousands of other 6 x 4 users want a solution which applies to their machine-- and noyt anyone elses;s.
Therefore I look forward to what might be the answer to my problem.

Speaking again, getting two bits of metal to do the job is simple and cheap. Cutting two bits of round metal does NOT require changing a machine to do it.
I can only apologise if my comments might be somewhat offensoive but I actually gave John Baron a part complete set of Mk1 castings beause I had and still have no use for them nor find the machined onne on my working Quorn suitable to my future requirements.
So My apologies if there if difficulties between us might cause disagreement ot inded friction.

Hello ,

I was already fearing that I missed the point. It happens to me too, that I fail to explain my problem. Sometimes I even get unpatient and angry about the presumably "wrong" answers.

I gave it a go, to guess what I thought might be your problem. I put the setup on my machine to show what I am trying to say.
( The photo I just made for the post, to explain what I tried to say).
There is only one minute 14:30 to 15:30 were the setup is explained, it only happened to be in a video about rotary table adapers. (coincidence)

Maybe someone finds the setup useful anyway.

Greetings Timo

 

[BaronJ]

Hi Guys,

I'm not actually sure quite what you mean Norman ! Timo's solution works only until the blade gets nipped by the clamping pressure.

Fitting a block in the blade gap allows support past the point of cutting, also extending the existing vise jaws allows you to grip material that is quite thin, but the maximum diameter is limited to about 3.5" simply due to the height of the vise jaws.

My way round that limitation is to use a "V" block stood on end. True you get a gap under the work with a steel "V" block, so a wooden one allows you to reduce the centre height. I also use an angle plate to ensure that the material is square to the blade. Once the material is secured in the vise I remove the angle plate.

Norman I hope that this solves your issue with cutting a piece off a short end !

 

[harborfreight8x12]

I have a couple of pictures of my Harbor Freight 6x4 bandsaw. I made plastic cover for the gearbox so that I could always see the lube level, since the first bronze worm gear was destroyed by lack of gear lube. Also, my wife's idea, I mounted the bandsaw on a heavy duty two drawer file cabinet on a Harbor Freight furniture dolly. Been happy ever since.

 

[BaronJ]

Hi Guys,

Thanks for the pictures. At least it won't fall over backwards when you move it !

I've also toyed with the idea of putting a clear plexiglass cover on the gearbox. I also notice that the worm in yours is steel ! The one in mine is bronze with a steel pinion gear driving the blade. The top up hole is a nice idea as well.

 

[timo_gross]

Hello everybody,

another setup, that no one asked me to post. I post it anyway. Presumably only works on blue machines. (sorry for the owners of green machines )
The hypothetical problem at hand. Cutting a disc from the 20mm left over of 1" rod. (I made the left over extra to be able to make the fotos)

I put the 20mm long piece into my ER40 collet block only about 5mm length are in the collet.

EDIT: In a post below BaronJ advises to be careful with using the ER collet only in the front, the advise is to put at least some piece of the same diameter in the rear end of the collet to prevent it from beeing uneven compressed.

I put my ER40 collet block into the machines clamping arrangement.

I cut off a small piece for demonstration purpose only.

The ER collet clamps at the very front quite O.K. For a saw cut good enough. For milling or turning I would not trust it too much.


I hope someone finds it useful. To be able to find the small piece in all the swarf, the mod that BaronJ made with the Al block maybe a good add on. (not for the blue machine, because it has a chip tray under the slot to collect some swarf)

Greetings Timo

 

[goldstar31]

Probably my minor proplem is to raid rge scrap bin and change the 'angle plates for higher and longer ones. Then fabricate a sort of Keats plate to securely hold the short round bar from 'wobbling and smashing the blade-- and worde.

I am a quite completent welder and could MIG =up the set up as really I should be able to think in the 'rpund' as well as in the flat.
Again, I recall ?Robert Smith writing this up in Advanced Machine Tool Work.


Snith describes a very useful Catspaw chuck as well as some useful msthematics on tool grinding

 

[harborfreight8x12]

Hi Guys,

Thanks for the pictures. At least it won't fall over backwards when you move it !

I've also toyed with the idea of putting a clear plexiglass cover on the gearbox. I also notice that the worm in yours is steel ! The one in mine is bronze with a steel pinion gear driving the blade. The top up hole is a nice idea as well.

You're right, it was my bronze gear that was destroyed, the steel worm gear was undamaged. I love the plexiglass cover, my bandsaw has a slight leak at the bearing seal, I'm just too lazy to tear it down and replace the seal. Kind regards, Al

 

[clockworkcheval]

Hi John( et al)

Digressing somewhat, I have never found a saisfactory method of holding down those large, round sort endes of metal. Perhaps you or other readers might provide information thatI certainly do not posses.

Expanding the topc, I am wanting to change the rotating workhead from a sinle graduated casting to the newer TWO bits of Mild Steel. I was able to obtain a short bit of 'round; but have to split it into two bits.

Therwise, it means making a special 'circulsr dovetail cut around the perfery of the block and it requires a rather awkward cutting tool.

I CAN do it, it follows the words and music of the Model Engineer's Workshop Manual description by Geo Thomas of how he constructed his small ungeared rotary table.
That machining is where the tool and cutter grinder such as the Stent and the Quorn possess 'certain advantages' which other lesser tools do not possess.

Worried Blue Eyes

The method to simply clamp a disc in the sawing machine with the aid of some additional pieces of metal looks is new to me and looks quite straightforward and practical. We - the members of my horological society - use sometimes a bit more cumbersome method. In making gears for clocks it is easier to get the nice cutting brass Ms58 in the form of round barstock than in the form of sheet. Brass sheet where I live can only be obtained in larger dimensions and sheet comes mostly as the tougher cutting brass Ms63. So with round barstock we are often faced with the necessity to cut a thin slice from a leftover disc. The alternative would be to scrap the leftovers and being Dutch we consider that not done. Our solution is to combine two leftover pieces to a 'dumbbell' . This dumbbell shape holds easily in the sawing machine if you support it with a length of flat stock. We can cut useable slices down to 2 mm thickness. I never tried it but I guess you can do exactly the same for leftovers of round steel stock. I made some pictures: soldering the first disc on the electric cooker, soldering the second disc, the finished dumbbell, dumbbell on sawing machine, set up for a slice of 2 mm.