Thread: Table Mounted Jigsaw

Apologies haveabeer. I thought I had responded to your kind offer, but it would appear I only got as far as the thought process.

I have gone down the table path far enough now that I am committed to this avenue of attack.I actually got a little further along today and will have to post some development shortly. However, your thoughtfulness and generosity is much appreciated. Also at some time I will be pensioning off my Triton saw table, when I get around to restoring a serious old style table saw I have.

Regards
Paul

I did advance a little on the contraption today but took no pix so I will have to let that slide until tomorrow.

So perhaps I can take the opportunity to address the scrollsaw suggestion mentioned by both Handyjack and Chief Tiff early on in the piece. I did indeed consider a scroll saw and in fact I found a design on the net that utilises the table mounted jigsaw and a spring on the top of the beam. The scroll saw is welded/braised/soldered to a broken or cut down jigsaw blade. The jigsaw still produces the reciprocating action needed for the scroll saw.

At first glance this was a very attractive option. In fact I could have both. On top of that I have these blades:

P1060049 (Medium).JPG

I think there is more than 1Kg of them . I bought them on a whim: Oh, OK, in a fit of madness, if you prefer, thinking that they looked like scroll saw blades. However they are 12" long (300mm for those of you born before 1990)

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Even the finest of these blades is only around 8ppi. The figures on the blades are the widths at 4.3mm, 5.8mm, 8.6mm and 12mm.

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I had some discussion with Matt on this subject as during the lockdowns we were in touch and he was anxious that I was gainfully employed, not wasting my time or lolling about on the longe watching Netflix.

The discussions were not conclusive but I have an almost unshakeable belief that they re the blades used for slicing bread. Whether they can be converted to a coarse scroll saw blade i don't know. They would have to be cut down, as I believe a scroll blade is around 125mm, and a new hole drilled for the top pin. I actually think a scroll blade would be a little to fine for the work I would put it to. 24mm thick Forest Red Gum and other similarly dense hardwoods might give a scroll saw a work out, but that is me speaking without any experience of scroll saws. If these blades are indeed intended for slicing bread they may turn up their teeth at hardwoods. I may try fitting one to a hacksaw frame to test one.

I also have old plans for making scroll saws out of re-purposed Singer sewing machines, pipe and pipe fittings, but that is another story.

For the moment I will concentrate on the jigsaw.

Regards
Paul

I don't think those blades would cut it in a bread slicer; they are far too coarse and should probably be made from stainless.

I reckon they may be intended for frame or bow saws; the ones that IanW likes to build.

Originally Posted by Bushmiller

However they are 12" long (300mm for those of you born before 1990)

Shirley you mean after 1990? I'm 1970's vintage (just missed the first couple of weeks) and am fully ambisinestrous in either Metric or Imperial.

Originally Posted by Chief Tiff

I don't think those blades would cut it in a bread slicer; they are far too coarse and should probably be made from stainless.

I reckon they may be intended for frame or bow saws; the ones that IanW likes to build.



Shirley you mean after 1990? I'm 1970's vintage (just missed the first couple of weeks) and am fully ambisinestrous in either Metric or Imperial.

Yes of course it should be "after" and the other typo is the "longe" which should be "lounge"; not even "chaise longue!"

In fact Matt said the same thing about the blades. He felt they would be stainless if they were for food, but the teeth seem too coarse for a turning saw. However I will try to insert one in a hacksaw frame to see if they stand a chance of cutting timber. So many things to do today .

Regards
Paul

Paul,
Do the blades have a set on them?.
My morning coffee rational, is why would you bother putting a set on a blade designed only to cut Bread.

Cheers Matt.

Originally Posted by Simplicity

Paul,
Do the blades have a set on them?.

The light and dark shading on alternate teeth suggests so.

Jigsawblade.JPG

Originally Posted by BobL

The light and dark shading on alternate teeth suggests so.

Jigsawblade.JPG

Yes I saw that hence my question to Paul.

Hopefully he can confirm our observations.[emoji6]

Cheers Matt.

Matt and Bob

I can confirm your suspicions. The blades have set: Quite aggressive in fact. I will make a few more observations. I just came back into the house for some checks regarding the jigsaw itself.

Regards
Paul

I did get to do a little more work today, although it took me all day. Is that a little bit weird sounding? You don't have to answer that one if you don't wish.

By that I mean I spent the day chasing bearings and then I spent the rest of the day looking for bolts that were a suitable diameter to fit the bearing, then looked for washers. Then I realised the back bearing was just too big. I went looking and found my tub of small bearings and there were two just about the right size for the side bearings and another, slightly larger, for the back. I am not sure why I was unable to find these before.

I clamped the timber temporarily in place.


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The vertical timber holding the bearings needs to be cut off at the top. I left it long so it was not too fiddly to work with and the vertical slot needs to be extended downwards. I would have like to have used Tee nut inserts so I could use bolts, but I did not have any to hand and the hardware store had closed so I used 1/4" coach screws. I may still be able to go down the bolt track if the coach screws work loose in time.

P1060146 (Medium).JPG


The bearings have a small amount of lateral adjustment and as you can see in the pic above the right hand bearing could be adjusted in about 1mm. A quick run of the saw indicated that in principle everything is good. I chamfered the timber and glued them in place in the chanel. It will cure overnight. The blade I used to set up is an extra long specimen and I still have to check to make sure all blades including the small curve cutting examples are supported.

Tomorrow I hope to start tarting the device up a little.

Regards
Paul

A little more information as I had to disassemble the arm for painting and varnishing. This is what is behind the washers:

You can see here the provision for lateral adjustment of the bearings. The idea to my mind is that they barely touch the blade.

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On the "scroll" saw blades for a moment I fitted the widest blade to a hacksaw frame. It is about 4 1/2ppi so really coarse and the cut is correspondingly rough

P1060150.jpg

These two pix are a cut in Forest Red Gum. The smooth cut is with a 7ppi 24" rip saw (A Simonds No.10 from 1901 - 1905, not that you needed or wanted to know that )

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I dis try two other blades but the hole I had to enlarge so it would fit on the hacksaw frame broke out of the blade as there was insufficient blade material. I will have to re-think that. Incidentally the blades are quite hard and not easy to drill.

Regards
Paul

Paul,
I’m completely confused,some would say easily done.
I know the design brief was so you can cut out the waste from inside a saw handle,
How do you open an close the machine ? I think it’s far Beyond a contraption now.
To place the saw with in the area to cut.
(Did that all make sense[emoji3064])

Also ,am I right that your last two threads have been basically about hunting and gathering bearings ?[emoji6].

Cheers Matt

Originally Posted by Simplicity

Paul,
I’m completely confused,some would say easily done.
I know the design brief was so you can cut out the waste from inside a saw handle,
How do you open an close the machine ? I think it’s far Beyond a contraption now.
To place the saw with in the area to cut.
(Did that all make sense[emoji3064])



Cheers Matt

Matt

Anybody other than you I would agree would be completely confused. The blade will still have to be removed from the jigsaw to cut out the waste from the hand hole but this is very simple. A lever has to be flicked and out pops the blade. Inserting the blade is only slightly more difficult providing there is good lighting and you have not had too much to drink. A little sawdust around the aperture seems to help for location.

Regards
Paul

Originally Posted by Simplicity

Paul,

Also ,am I right that your last two threads have been basically about hunting and gathering bearings ?[emoji6].

Cheers Matt

Matt

You've nailed it! I am more of a gatherer (scrounger) than hunter, but so far you have only had the abridged version. The original back bearing had a 12mm hole and I had to find a bush so I could use a smaller bolt, I had some stainless steel tube that was 1/2". I ground that down and polished it so it fitted the bearing and then I could use a 10mm bolt before I realised it was still to big, but I spared you that story. So really until now you have only heard the half of it. Fortunately I found the tub of small bearings I had mislaid and have ended up with the selection you have seen above. Also no machines or router bits were compromised or destroyed during this process. Therefore no surprise visits in the middle of the night from the RSPCM. (M = Machinery)



Regards
Paul

I assembled the contraption (don't really know what to call it) today as the finish had dried and it was time to test to see if it actually worked.



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I already had a saw handle sketched out together with the template so all that remained was for me to remove the template and start cutting.

P1060168 (Medium).JPG

Immediately I saw some shortcomings. The blade I had originally inserted to take measurements was the longest blade I have. The blade that is required for tight curve cutting is the shortest blade I have. It reaches the back bearing, but not the lateral bearings, which is really the prime consideration.
P1060171 (Medium).JPG

I cut as much as I could using the wider (and longer blades, the two middle ones) seen above and only used the curved cutter for the hand hole and and some of the tight bits on the outside.

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Frequently I was unable to keep cutting in a continuous cut and had to chop off multiple pieces.

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Finally I re-attached the template reade for flush trimming with the router.

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So what did I learn. It is clear that 24mm thick Forest Red Gum really tests the boundaries and it is necessary to have exactly the right blade The bigger blades I used did not like cutting with the grain at all. So it seems I would need to use a dedicated ripping blade for that and the curve cutting blade for tighter radii was really too short as it did not contact the lateral bearings.

I will need to make up a new bearing holder with smaller bearings if I am unable to find a longer curve cutting blade, which might not be even available. One thing I was able to adjust was the back bearing. Two problems occurred there. Firstly it sat too far from the blade, but I solved that by putting a washer between the beam and the bearing support. Secondly I had tightened up the bolt too much and it would not rotate. Slacken off the bolt: Easy.

For the moment there is no advantage in using the table mounted jig saw other than being able to cut closer to the line making the next operation easier.

Regards
Paul