Thread: Firewood splitter design

Actually it will stiffen the heck out of it, I'm talking about the flat on edge and welded to both the flange and web. And to both sides as well, with the opposing side done so it crisscrosses, which will stiffen it even more.

After having a look at the image again, it looks like the UB is a piece of 250 UB 25 which would match with the Web and Flange thickness quoted. Web should be 5mm and flange 8mm.

A 250 UB 37 would probably been more benefical here with minimal bracing/webbing

The mast is 125mm wide which means 60mm depth per side. I have a precut length of 100mm X 6mm.(Already on the splitter) I even have some 130mm X 6mm. They are toerail sections removed from catwalks at work when expansions etc were done. I got them from the scrapbin. I even asked for permission. I don't have anything like 60mm X 5mm. This is one of my objections. I can see how this would stiffen up the mast. My other objection is that this would require a lot of metal strap, a lot of cutting and a lot of welding. This method therefore would be substantially more expensive than my current idea which would require about 1000mm of 60mm strap and some welding rods and electricity.

If I could see a substantial benefit I would consider it but I don't see this myself. Over the length of the mast where the slide operates you indicate a vertical line which appears to be another length of strap mounted vertically, outside the space of the slide mechanism. The criss cross straps attach between this strap and the rear flange. This would not add any rigidity to the front flange of the mast at all. If this section was left out it appears to me that there would be no difference.

I was told by a friend who is self taught about many things, that in order to visualize stresses related to a situation like this, picture each contact point as a hinge. Therefore the connection between the front flange and the web is a hinge as is the rear flange and web, all welds etc. Looking at the situation in this way shows that neither method has any effect on the front flange. The strength here will be supplied by the extra angle and lots of tie in welds.

Attachment 212721

I plan to box in with strap as shown by the short lines then reposition the brace as inicated by the long line. These will all be tied in together and the added angle will also be tied in to the cross braces. It is true that having shorter lengths and steeper angles can add overall strength but I think that it is not warranted given the amount of extra work and cost involved. For the mast to twist it has to stretch one of the braces and I don't see that happenning.

This splitter has operated now for about 7 years without problems and the paint cracking is just showing up. This is with a 5mm web. If I increase it with 2 bits of say 65mm X 8mm angle (cut to suit) and spacers. That is going to increase the strength of this section by over 300% ignoring the spacers. Tying down the top of the mast with the brace in the correct position will mean that the slide section twist will then be resisted from above as well as below. I have also thought of using RHS instead of strap for the cross bracing.

Thanks for the suggestions tho as sometimes (for me anyway) suggestions like this can often lead to further ideas. What I need to do now is to find a realy twisted bit of wood and observe what is really happening just to be sure.

Dean

The method you've shown will still twist to some degree but no where near as bad as what it is currently doing.

The vertical strap where the slide is, is still tied back to the flange by the crisscrossed pieces as it has been boxed in and I know for a fact that it will work, as I have done work like this previously in the past. Even 40mmx5mm strap will fix it, it doesn't have to to right out to the edge of the flange, just needs to be stitch welded to both the web and flange.

Originally Posted by devnull

Have you seen this one?

Monday Monday - YouTube

No. That is a new design for me. A lot of info like this is available on YouTube but due to my limited internet connectivity I am limited. I have looked on YouTube for splitters and seen some horrendous ones and some good ones but none I think are as good as mine. That design would have more hydraulics than usual. My lift works off the knife movement using a cable and has a lock to hold it up. Splitting a 900mm diam ring of redgum on that splitter with one person would be tricky. What do you do with the other half when you don't have someone helping. My table is smooth and flat and is 450mm wide and about 1200mm long. Add the lift which is sitting flat and level with the table and there is a lot of room for big bits of wood.

Also I can have another person rolling rings on the lift as well if I get the timing right. In the video I noticed he lifted a ring off the pile, carried it over and put it down on the base. I would have thought that rolling rings was easier. That is the idea for my lift. I can also use a sack truck if it is easier. I guess this splitter was mounted on the ute (truck). I would never carry cut wood over to the ute like that. Lots of wasted effort. My splitter is moved by a ride-on mower but is normally used freestanding. I usually try to split from one side to the other with a wood pile or trailer right next to it.

I cannot understand why almost all splitters are made with such poor design. I looked at a video a couple of days ago where this guy was going on about his fabulous new splitter and then said that if the rings (logs) are too big it can be operated in the vertical position. He was squatting as low to the ground as it is possible to get. Great posture, not. Then I looked for the controls. If his arms were 6ft long he would have been able to reach them, maybe.

I designed mine the way I did because I had heard about my neighbours splitter and had a look. He okayed me taking photos. At that stage they(splitters) were expensive machines and this was the only one that I had seen that was user friendly. It was simple to me. A table and lift was the only safe and posture friendly method to use. I worked it from there.

Dean

Originally Posted by Acco

Actually it will stiffen the heck out of it, I'm talking about the flat on edge and welded to both the flange and web. And to both sides as well, with the opposing side done so it crisscrosses, which will stiffen it even more.

That is how I pictured it and I agree it will stiffen the mast as I did say but it will not stiffen the area where it is needed most and neither will my method. I just don't believe that I need that much stiffening at that much cost in time and money.

Dean

You need to look at the overall picture, most of the twisting action will actually begin at the top where the ram is mounted to the UB.

You don't need to go to the extreme amount that I've drawn in, I just did that quickly to give you an idea. You'd get away with just three pieces to the top of the slide and same again behind the slide.

Originally Posted by Acco

The method you've shown will still twist to some degree but no where near as bad as what it is currently doing.

The vertical strap where the slide is, is still tied back to the flange by the crisscrossed pieces as it has been boxed in and I know for a fact that it will work, as I have done work like this previously in the past. Even 40mmx5mm strap will fix it, it doesn't have to to right out to the edge of the flange, just needs to be stitch welded to both the web and flange.

It is tied back to the rear flange which has no effect. The damage from twisting is occuring in the area covered by the slide just behind the front flange which will be outside the area covered by your straps. The twist originates at the knife slide and the top of the mast twists with it. As I mentioned earlier, picture a hinge between the front flange and web and you will see that boxing in the rear will not do much except concentrate the flex in the web to the unboxed section. Again I must say that in my opinion the cost far outweighs the benefits. If there is a benefit worth considering I don't see it.

I really need to watch closely while the twist is occuring and maybe hold it slightly twisted so I can examine the whole mast but at this point I believe that the main area which needs working on is the area where the knife slide operates. I can only see one way to do this. I have heaps of 6mm plate and strips as mentioned. I have some heavy angle that will suit. I have 50mm X 3mm RHS. I have 45mm X 5mm angle. I have some 30mm or so X 2mm. I don't have anything less than 100mm X 6mm except that. To buy material as you have suggested would require a trip of nearly 200km return plus the cost of the material. I hope you can understand why I need to have a good reason to follow this path when I don't understand how it can offer much benefit.

Dean

Originally Posted by Acco

You need to look at the overall picture, most of the twisting action will actually begin at the top where the ram is mounted to the UB.

You don't need to go to the extreme amount that I've drawn in, I just did that quickly to give you an idea. You'd get away with just three pieces to the top of the slide and same again behind the slide.

We seem to be leap frogging posts. Yes I need to look at the overall picture but I think the twisting is at the knife. What would cause the top to twist other than the twist of the knife. I will try to have a look in the morning.

Dean

Dean

Your splitter has lasted a long times already. I suspect that from what you say only a modest amount of strengthening will be neccessary. If you observe the twisting forces and take some remedial action I'd say it will go for a good number of years more.

It would be galling to to nothing and suddendly have it let go under the pressure of a particularly nasty lump of timber. Then there would be a hugeamount of work to do.

It is good design. Do you have a patent on it?

Regards
Paul

Originally Posted by Bushmiller

Dean

Your splitter has lasted a long times already. I suspect that from what you say only a modest amount of strengthening will be neccessary. If you observe the twisting forces and take some remedial action I'd say it will go for a good number of years more.

It would be galling to to nothing and suddendly have it let go under the pressure of a particularly nasty lump of timber. Then there would be a hugeamount of work to do.

It is good design. Do you have a patent on it?

Regards
Paul

That is also my thoughts on this problem.

When I built it I had no idea it was any different to other designs available. I thought it combined all the best features of what I had seen and that was it. At that time wood splitters were not as common as they are now and a lot more expensive. A lot of what I had seen were tractor mounted.

Dean

Originally Posted by Oldneweng

What would cause the top to twist other than the twist of the knife.

I didn't actually say the top would twist, I said most of the twisting action will actually begin at the top, what would be happening is that when the knife engages in the wood, all the force is transferred to the top which would then start the twist, which is usually at the point furthermost from where the force has.

By adding strapping as a crisscrossed web you are therefore strengthening the UB by stiffening as you've essentially boxed the two flanges to each other. Another method to try and would require very minimum amount of material and labour, is to tie the top of the beam to the outer edges of the table. See attachment below.

I thought you might be amused to see the last firewood splitter I made.

Well. I know, it's a block splitter really. It just gives an axe a little more weight and an increased splitting action. Two pieces of leaf spring and a couple of blocks of steel. A huge round arm action and away you go. have a rest about every ten blows.

I think I can hear Dean cringing from here.

The handle is interesting. I used to supply timber to a tool handle maufacturer and they gave me this one. Unfortunately it was a reject. The curve in the handle is not a trick of the camera. It is real. I have to make allowances.

The ridges on the handle are because it was their racing model for use in competition except that this axe is in Spotted Gum and for the racing model they used imported Hickory. The ridges were achieved by running the lathe at a slower speed still on automatic feed. It does give superior grip.

Regards
Paul

Originally Posted by Bushmiller

I thought you might be amused to see the last firewood splitter I made.

Well. I know, it's a block splitter really. It just gives an axe a little more weight and an increased splitting action. Two pieces of leaf spring and a couple of blocks of steel. A huge round arm action and away you go. have a rest about every ten blows.

I think I can hear Dean cringing from here.

The handle is interesting. I used to supply timber to a tool handle maufacturer and they gave me this one. Unfortunately it was a reject. The curve in the handle is not a trick of the camera. It is real. I have to make allowances.

The ridges on the handle are because it was their racing model for use in competition except that this axe is in Spotted Gum and for the racing model they used imported Hickory. The ridges were achieved by running the lathe at a slower speed still on automatic feed. It does give superior grip.

Regards
Paul

Cringe I did not. I am happy to make stuff like that because at heart I am a tight a#s#. The idea has merit without a doubt. One of the advantages of block splitters is they are shorter across the cutting edge which allows greater penetration from the original impact. They act like a wedge as opposed to an axe which actually slices the wood. You know all this I know! Anyway if you had used a narrower axe or cut it the penetration would improve.

I am a fan of what I know as the Canadian Splitter. The square cyclone ones are a very poor example of splitter. I watched a video of reviews of splitters this morning starting from a beautiful example of the Canadian Splitter with a nicely shaped raised section which was polished like a mirror. Another thing which would improve yours. This review moved on to the ultimate. The standard horizontal / vertical jobbie with the worst posture position available on the planet. I know, I am biased but I don't care.

I have a splitter (Canadian) with a fibreglass handle which has been refitted once and I have a replacement handle and the resin kit to replace it because the handle is just about to need replacement. I bought that replacement about 8yrs ago. Still going strong. Does a good job of holding up the wall in my shed extension. The wall has not fallen down yet.

Unfortunately the reason for the lack of use of this splitter and the building of the hydraulic one is health related. I have a rare Auto Imune Condition which has caused a noticable loss in lung capacity. Your comment

have a rest about every ten blows.

for me would be 2 blows and a much longer rest.

Anyway enough of manual splitting. I have checked the effect on my splitter of twisting the knife with twisty wood. It was very difficult. First I had trouble making it twist and I used some bad wood. It is hard to watch both the knife and the top of the mast at the same time so I had to jam it in the twisted position and perform some sort of measurement.

I got a bit of twist from a redgum fork which stalled the knife. I was trying to measure with a 3m long bit of 50mm X 6mm angle clamped across the edges of the 2 flanges alternately just above the knife and then as close to the top as I could get. The result did not match my theory so back to the drawing board. Actually I noticed about 30mm movement at the end of the angle when clamped at the top, between twisted and straight and very little movement when clamped at the bottom just above the knife. When I released the pressure to check the bottom movement I realised that the pressure had already been released. It took a long time to do all this. Several hours of walking back to the shed etc etc. The angle was heavy and hard to handle. The whole thing took too long so back to the drawing board.

Next I tried using the same bit of fork to get another twist. This time the splitter just went straight thru it. I have multiple pics of all this so if anyone is interested just ask and i will post them. Several horrible bits of now split wood later I finally got a decent twist and sprung into action.

Attachment 212804

This is the piece of wood with the knife twisted. It is not so much as a tough bit but angled. Normally I would have split this bit up the other way to avoid this. You can see the mark the knife has made sliding down the crooked grain all the way from the top. Once there is enough pressure on the table the wood stops moving and the knife starts twisting.

The setup as shown in this pic is for the bottom measurement. A bit of 2 X 1 pine (green painted) is clamped on edge against the face of the flange just above the knife. The other end of the pine is positioned to almost reach the lifting frame which I have clamped in a vertical position to act as a datum point. Photos taken of end of pine location in relation to vertical member of frame. I was looking for sideways movement of the end of the pine.

Quickly move the pine to a position to clamp against the face of the mast as high as I can get it but angled down because it still had to line up with the lifting frame member. I love these trigger clamps. Photos taken.

Now I released the pressure on the knife making sure it was as close to the same position as possible with the chunk of wood still jammed on it. I then repeated the rough measurements as outlined above including photos in both positions. The photos are all out of focus as it was too bright to check on the screen and I was trying to be quick.

They still show the results however. There was no detectable difference in the position sideways from the top clamping but the clamping position just above the knife showed a variation of about 12mm. There was also a very noticable twist in the pine caused by the flange face being twisted more at the knife than above it. In other words the main part of the twist was localised at the knife position. This is what I had observed in the past. The knife and its slide which is clamped around the mast is doing the twisting, some of which is transferred up the mast.

I also looked at the flange face from a right angled position so I was looking across the face. I could see twist from the knife area which was not visible at the top, when compared with other lines of the splitter. The difference between the back edge of the table and the face was definitely visible.

My conclusion at this point is to continue with the plans I have unless someone can improve on them within a reasonable cost. While doing this checking I also noticed that the flat face of the flange is now concave in the knife area. Not real good.

Attachment 212814

This is a pic showing the telltale mast fatigue. This is on the right side as operating it. The other side was photograped but is not as obvious as this.

Attachment 212820

This is a pic from just after I finished building it. It is the only one I can find showing the knife design properly. I am interested in comments on this too as it is the only one I have seen like this. It is not my design. I went to a local engineering shop to enquire about the steel to make a knife and when he reaslised what it was for suggested a design that they had used before and gave me a good price for the whole finished knife.

I also asked for the backing plate to weld it to but when I picked it up it was too thin (I already had the position for the ram setup) which would put the ram on an angle inwards. This plate was also badly twisted. Probably cut with a guillotine. Not good for a plate (carriage) to run against a flat surface. I used a piece I already had that was the same thickness but flat and used some packing to bring it out to position. This piece is also much longer.

The knife is 25mm plate, 300mm X 300mm except with a section cut out to leave a 50mm X 50mm extension on the outside end as can be seen in the pic. Both bottom edges are cut to a point using just an oxy. According to the engineer the short front knife section starts the split with very little effort due to the small area, allowing the rest of the knife edge to then follow. Much like the narrow edge on a hand splitter. I have never seen reason to deny this. Two bits of 50mm X 50mm X 6mm angle are welded across the centre of the knife to ensure the wood opens right up and does not jam.

I have also not seen this type of knife in use anywhere else. I think one of its benefits is that it is much deeper than others. This is also one of its weaknesses. When I split big rings I do it around the edges, not through the middle, til I get its diameter down a bit.

I have had some serious bad bits of wood jammed on the knife when the hydraulics stalled. I have a length of steel pipe to place between the bottom of the ram mount bracket and the wood to reverse the knife out but now I generally just put a bit of redgum house stump under one edge of the wood and have another go. This cocks the wood to a different angle and usually loosens it enough to remove and try again a different way.

I must look up some specs and calculate the capacity one day. I really have no idea. Just looked at the picture above again and realised there was no cable for the lift at this point. Everthing is there but no cable. Even got the thimble ready at the top.

Dean