Thread: Ripping Bench Advice

i am collecting parts to build a number 2 beanch saw also.

motor size will depend on whether you are using electric or petrol.

from memory a petrol would need to be 5hp and an electric 3hp?

Rip style teeth
The obvious feature of a rip profile is its big deep gullet. The purpose of it is to rake out dust. To go with the grain, the style of a rip table saw blade has an aggressive +20 degree positive hook angle and plenty of side clearance. Usually a rip profile is flat on top as shown here. (Triple chip is seen on some varieties.) A flat shape or F style is also seen on a raker, but it has a bit less hook. It sometimes has the capacious gullet. A raker opens up combination patterns which are primarily alternate top bevel. It is inserted between and slightly below the level of the groups of other tips.

http://www.dekalbsaw.com/glossary.html

The biggest problem with doing it with a saw bench is physically moving (big) slabs past the blade. A 12" blade will also only give you 4" max deep cut anyway and I wouldn't be ripping to 5" with anything less than a 16" blade

Also for doing lengthy repetitive rips you need about a HP per inch for Aussie hardwood, so 5" needs 5HP electric - this means 3 Phase. Yes you can cut 4" deep rips with a 3HP TS but how many metres can you make before it overheats - I can do about 6 m and then my TS trips out.

There are many simple small CS solutions to break up slabs - have a look in Will Mallof's book on Chainsaw lumbermaking.

One solution is a mini-mill which when used with a small (50cc) chainsaw with 0.325 pico chain (smaller kerf than regular chainsaw) you will easily be able to cut 5 x 5 or more with these.

Handling the slab is much easier than running the slab past the blade, just clamp the slab to a pair of sawhorses so that the piece to be cut hangs over the end and move the CS with mini-mill along the slab.

I'd post some pics but picture uploading is not working form right now.

if you set up a good number 2 bench saw with rollers a infeed and outfeed then moving the slabs over the saw is easy. and lots faster than a chainsaw.

You can get 5hp in single phase if all else fails - but heavier and more expensive than equivalent 3 phase.

Originally Posted by weisyboy

if you set up a good number 2 bench saw with rollers a infeed and outfeed then moving the slabs over the saw is easy. and lots faster than a chainsaw.

I agree, but my main argument was if you use a 12" blade with just a 3HP single phase to continually rip at 4" the motor will die pretty quickly. I would love a number 2 saw bench but a dead circular saw cuts a lot slower than a live chain saw. If I was going to set up a ripping bench I'd be starting with a 16" blade, 5HP - 3 phase and a 500 kg bench.

It also really depends how many slabs you have to break up, where they are located, how big they are, and what other machinery you have available etc. If you have to resaw a lot of slabs, maybe you should have got a Lucas to start with. If the slabs are heavy (some of mine weigh 250 kg) a forklift will be needed to lift them onto the saw bench whereas a minimill I can break them down almost on the spot. My slabs are also scattered all over the south west of WA. A minimill can fit behind the seat in my van, so I don't need to tote and carry whole slabs, whereas a number 2 bench . . . . .? If you only need to resaw a few slabs at a time and if kerf loss is your major issue, breaking a slab down with a minimill or similar to where it can be handled thru a bandsaw is still one of the best options - infeed and outfeeds will be needed here too. A bandsaw is slow but you can rip ~12" depths which would require a serious blade on a sawbench.

Thanks for the replies. The biggest problem I face with my setup is there is no mains power. The last power pole is about 9km away from my work area and I was quoted approx $17,000 to be connected, and I had to supply poles. I run a 5kva generator to power the equipment I use so I am limited to smaller gear. At least there are no neighbours to complain about noise.
I have a Stihl 026 with a 16" bar, so I will look at getting a pico chain for it. So far my slabs aren't too big. I'd love to get access to trees so big I couldn't handle the slabs alone.
A big bandsaw would be ideal, but unless they make a petrol one, I can't run it.
My intention with the saw bench was to make a sled arrangement on rollers that I place the slab on. The only bit not supported would be the edge on the far side of the blade which would be the actual board being cut off. Sort of a heavy duty version of those big table saws that they cut full sheets of ply on. The weight of the table isn't a problem. I don't intend to move it. I'll probably build it outside my shed anyway, and just roof over it.
When I do get slabs too big to move manually, I have access to a small tractor with tiltable forks. I don't intend this for mass production. I just want to be able to slice up my slabs while minimising loss. I try to keep my timber in as large a piece as possible untill I need it. It takes a lot longer to dry, but its easier than trying to stick smaller bits back together.
I've only had a look around the local retailers and 12" seems to be the biggest blade they stock. A few places said they could probably get larger but it would be a special order and much more expensive. Most of my slabs are 2" to 3" thick, but I want to be able to cut as deep as 5" just in case. As a thought, wouldn't it be possible to run the slab through with a 3" cut, then flip it and cut from the other side? A lot of man-handling, but surely possible? It will go through the thicknesser anyway, so a small amount of misalignment wouldnt hurt.

yer i have the same problem no power to the mill site thow not as far away as u i cant afford to get it down there.

i have been toying with teh idea of a bench saw powerd by a chainsaw motor. i dont see why it would not work but power might be a problem.

tehre would be no problems runnign a bench of a petrol or deisel motor.

you could rip both ways but you would have to flip the slab.

as for blades give teh local saw doctor a call tehy will have second hand blades in many sizes or tehy can get a new one in any size lots cheeper than anyware else.
i recon i can get a 5" cut from the spindle and a 12" blade i have under the house.

Originally Posted by Ravvin71

I run a 5kva generator to power the equipment I use so I am limited to smaller gear.

A 5KVA genny will power a nominally rated 3 HP saw but I wouldn't want to be ripping more than 2" deep cuts in Aussie hardwood with it on a continual basis. A 5KVA genny will not actually give 5KVA more like 3.5KVA, while a nominal 3HP 240V motor will draw as much as 1215 A ripping stuff above 2" . Thus the power supplied 3.5KVA, compared to the power required 15 x 240 (3.6 kW or KVA) are just too close for comfort for continuous operation. I'd be looking at a 7.5 KVA genny minimum to drive this setup.

A big bandsaw would be ideal, but unless they make a petrol one, I can't run it.

You can run a 2 or maybe even 2.5 HP all day on a 5KVA genny and rip 12" but it will be slow.

My intention with the saw bench was to make a sled arrangement on rollers that I place the slab on. The only bit not supported would be the edge on the far side of the blade which would be the actual board being cut off. Sort of a heavy duty version of those big table saws that they cut full sheets of ply on. The weight of the table isn't a problem. I don't intend to move it. I'll probably build it outside my shed anyway, and just roof over it.

Sounds good.

When I do get slabs too big to move manually, I have access to a small tractor with tiltable forks. I don't intend this for mass production.

Excellent

I just want to be able to slice up my slabs while minimising loss. I try to keep my timber in as large a piece as possible untill I need it. It takes a lot longer to dry, but its easier than trying to stick smaller bits back together.

That's my approach also

I've only had a look around the local retailers and 12" seems to be the biggest blade they stock. A few places said they could probably get larger but it would be a special order and much more expensive.

Yep a good 16" blade is going to cost double the price of a 12"

Most of my slabs are 2" to 3" thick, but I want to be able to cut as deep as 5" just in case. As a thought, wouldn't it be possible to run the slab through with a 3" cut, then flip it and cut from the other side? A lot of man-handling, but surely possible? It will go through the thicknesser anyway, so a small amount of misalignment wouldnt hurt.

This works in pine with 4" cuts, but not well or not at all in Aussie hardwood. When I do this with my 3HP table saw it overheats and trips out after a couple of metres of cutting. Doing this often enough it will kill the motor and genny.

The types of saws that do that blind cutting continuously (eg Lucas) have power (HP) to saw diameter (in) ratios of over 1:1 or more typically 2:1, whereas a 3HP with 12" setup is 1:4. Also to do this sort of ripping the electrical motor class needs to chosen appropriately to supply full power across the RPM range, thats why 3 Phase motors are much better at ripping than single phase.

if your constraints are a 5 kVA genny, a 2HP bandsaw with good in and outfeed tables are probably the way to go. A minimill will still be useful to rip the slabs down to size so they can more easily be handled onto the BS.

If you can upgrade to a 7.5 KVA you can then drive a 3 HP TS but you still won't be ripping 4" let alone 5" with 12" blade.

Seen this?

It is just another alternative to a minimill then go the bandsaw.

I'd hunt around for an old saw bench of the sawmill variety and adpt it to run on the pto of that tractor you mentioned. I did this with a bench that ran a 36 inch saw and drove it with a David Brown tractor (40hp approx) The rollers were hooked up to a holden gearbox which provied reversable friction through first and reverse gears. Since then I have graduated to a professionally built pto driven bench that I drive with a fiat 880 tractor. It has rollers powered by hydraulic friction. Great for edging slabs and the odd 6x6. It has a 44 inch blade that will do about a 13 inch cut. Built in sawdust blower etc. Still needs more power though.

Alternatively an aluminium straight edge, 2 cramps and a makita power saw will rip the edge of and do that double cut you mentioned.

cheers
steve

i love fiat tractors

go to the local sawmill most likely thewy wil have a few old saw benches you can do up that they will sell you.

that pto idea is a good one. like the old firewood benches.

the one local mull used a tractor to runn a generator that powerd all tehre gear.

will investagate further.

Originally Posted by Stopper

Alternatively an aluminium straight edge, 2 cramps and a makita power saw will rip the edge of and do that double cut you mentioned.

Be my guest, but you'll cook the saw blind ripping continuously in thick aussie hardwood. Portable saws are not designed for continuous blind ripping like a table or bench saw.

Some "interesting" saw benches on utoob.

"http://www.youtube.com/watch?v=BZbbJyJSHR4"

"http://www.youtube.com/watch?v=w_22xGwZ0sI&feature=related"

"http://www.youtube.com/watch?v=o8A1H15Ohw0&NR=1"

Cheers

yes verry interesting.

A couple of observations here. It is essential that saws of this size when used for ripping (not cross cutting as shown in the u tube videos) must be covered with a hood. Many sawyers have been scewered by timber propelled back from the top of the saw.

The other point I would like to add is that you usually find old benchs like this in the Land Newspaper and other rural advertising areas. There was one advertised in the land in October last year - PTO drive one man bench. (I checked it out but it was designed for sleeper cutting and the hob would not open wide enough for slabs.

cheers
Steve