Problems cutting dense timber

[Iain]

I just acquired a piece of very dense timber, unfortunately I do not know what it is but it is about 125mm square and 600mm long.
I wanted to take a few slices 20mm thick off the timber and I put on a new 1/2" 3tpi blade on my saw (14" 3/4HP).
I managed to cut about two thirds of the way through and then all the screws on the blade guides came loose and the fence came loose. It was all tight when I started.
I removed the timber and started again from the other end and the whole lot came loose again. There was little or no vibration.
I might add that cutting was very slow and I did not force the timber through.
Any thoughts on what the problem may be and I realise that the timber is extremely dense.
I think the blade is OK as I put a piece of 2" pine through afterwards and it cut with no effort.

[barrysumpter]

Hi Iain,
I just spent some time cutting 30 year old redwood posts 100x100 x about 12". Thick and dense.

I wanted 10mm slices.

Tried the first on the bandsaw since the bandsaw could manage the full 100mm.
It took about 5 mins for this first slice.
The cut was really rough needing further sanding etc...

I decided to run the next slice thru the table saw - ripping once turning over end to end and ripping again. Leaving about 12 mm center to finish with the bandsaw.

------------------
Thanks,
Barry G. Sumpter
Proud Tritoneer

[This message has been edited by barrysumpter (edited 25 April 2001).]

[Iain]

Thanks Barry, that had been a consideration but I have a problem with the TS, it scares the hell out of me. We sit there and look at each other, like a Mexican standoff. TS wins every time. Unless someone can offer some suggestion on how to overcome my TS phobia. It is a 10" with a CMT ripping blade. To date I have only used it for ply and similar light pieces.

[barrysumpter]

Dude!

I know exactly what you mean.
After I:
got over the scream of the motor,
studied the users guide,
studied for a week on the safety features,
lowered the blade so only a mm above the work piece,
slipped on gloves, goggles, ear protectors,
and dust mask
and lots of prayer and meditation,
I finally got up the nerve to ask SOMEONE ELSE to push the first few work pieces thru.

Once I could stand behind and have a good sticky beak and see exactly how it was done, I couldn't wait to get my hands on it.

And yep, two years later (Easter) still got all ten fingers, clear lungs, 2 working eyes, and my hearing ain't too bad neither. Although it fades in and out when the wife and child a'callin'.

Regretably missing big toe toenail growth from dropping a mdf sheet on it my second weekend of official woodworking as a hobby. Hurt like hell for hours. Still hurts when I think bout it. Really mad and contemplated stopping wood working 'cause I didunt tink I wus smert enugh nut to hurt meself'. Wife talked me into sticking with it. Love ya babe.

Be careful, have a go, and let me know.


------------------
Thanks,
Barry G. Sumpter
Proud Tritoneer


[This message has been edited by barrysumpter (edited 25 April 2001).]

[ubeaut]

Ian - Try more tension on the band saw blade it is almost impossible to over tension, and the tighter it is the better and more acurate it will cut. The screws on the guides are a bit of a worry, as for the fence. Do what I did chuck it away and replace it with a timber one that can be clamped to the table.

Draw a straight line on a piece of timber then cut to the line by hand on the bandsaw, that the cut will seldom run dead straight. More often than not it will be at a slight angle to the left or right. Setting your fence to match this angle will also help, however this angle can change as the blade becomes blunt or when you change blades, etc.

As for the table saw. Here is some very simplistic advice that may help. Make sure the fence and blade are adjusted right. Stand to the side and feed the timber smoothly. Finally and most importantly. Keep anything that bleeds well away from the blade.

I have a couple of excellent videos that will help with both of your problems, bandsaw and especially the table saw. Most inspiring. Maybe they will help, however Doorstop has them at present.

Cheers - Neil

[Iain]

Thanks Neil and Barry, I may try the tablesaw with a gap in the centre to finish with the bandsaw, can't explain why everything is coming loose and I have used this saw for the past two years without any problems. Cuts OK, blade tension just fine. Could be a dud blade? and I realise that pine is not really a challenge to a bandsaw. (I remember using a stihl 9 something with a blunt chain, didn't really make a lot of difference)
The screws on the saw are the knurled finger tightening ones and I know if they are tensioned too hard the casting snaps, guess how I know that one?
I might try a jig to hold the timber and throw away the fence as it is rarely accurate, a bit like the mitre gauge which is spot on, plus or minus 10 degrees.
If I win Tatts I might trot down to carbatec and buy that Hitachi bandsaw with the five inch wide blade.
With the TS would you suggest one pass each side or multiple passes and if so how deep for each pass.

[S Hayward]

Hi Iain
Couple of things about the table saw. Firstly, if you follow Barry's lead and put on the gloves get ready for a nasty surprise in the future. Gloves and revolving machinery are not a good combo. Also, if ripping right through be very careful if you only have a little bit of blade exposed. If you consider the angle of attack of the teeth as they enter the timber with the blade just through, the force is pushing the timber back at you. This can sometimes cause a board to lift off the table and even end up smacking you in the face. Solution is to lift the blade higher. This means the teeth are actually pushing the work onto the table. As Neil says, keep the flesh away, use the guard and a good push stick and if it is looking a bit hairy get some one to tail out. Don't pinch the boards together on the out feed side, very nasty, don't let them drop, also very nasty. Set up an extension table if necessary, not rollers. Rollers tend to guide the timber either left or right. Beware all you with the Triton and roller stand. When ripping a deep board several passes can be a good idea. We have a 5hp 3ph motor running our saw and still often rip in several passes. Depth you can rip depends on hp mainly but around 20mm at a time should be OK with your set up. You can rip right through to half way but be careful. If you are not confident leave a bit in the middle and finish on bandsaw as suggested previuosly.
Maintain a healthy respect for the tablesaw and even a little fear but don't be timid. This is when they tend to bite. It would take a few hours practical to really get to know a saw so I hope this at least gives you a few pointers.
As a disclaimer, I take no responsibility for any operator following any advice given!
Cheers
Shaun

[Barry]

Ian,
Have a couple of suggestions!
First as already mentioned, use a timber fence tall as you can make it and supported with blocking, (L shaped with plenty of surface area triangle support blocks and notched in the centre enough for the guides to be as close as possible to the surface of the timber your cutting)
To use a fence like this determine the drift of your blade (every blade is slightly different)then clamp your fence to the table. This takes a bit of time, but when you cut dense timber it is very important to get just so.
There are two ways of assisting the cut.
1) use soluble oil mixed with a little water.
This is achieved by setting up a container with a small feed tube a tap to regulate drip flow.Tape the tube so it sits just in front of the cut.(oil avialable from your fuel depot)
This process makes a little mess but is the best if you cut a lot of thin strips. I use this to cut 12mm slices 200 to 250 thick up to 4m but mostly 1.2m
2)No mess!use bees wax applised to the back of the blade before and during the cut.
As also mentioned by others blade tension is more important when cutting dense timber. Just remember to let off tension when you finish for the day.
Final tip for now. Roller supports for in and out feed make the whole thing a lot less exhausting and help maintain finner control.
Good luck!


[This message has been edited by Barry (edited 29 April 2001).]