Safest way to rip boards in half?

[cusimar9]

I'd like to know what the safest way is to rip a board in half along it's thickness on a table saw.

So if I have a board which is 1m x 200mm x 20mm, I would end up with two boards each 1m x 200mm x 10mm (minus the blade kerf)

On a 10" table saw this can be done in two passes, making the first cut then by flipping the board over on it's edge and making the second cut from the other side.

How do others make these sorts of cuts? What jig would make this cut safely?

 

[bugbear]

I'd like to know what the safest way is to rip a board in half along it's width on a table saw.

So if I have a board which is 1m x 200mm x 20mm, I would end up with two boards each 1m x 200mm x 10mm (minus the blade kerf)

On a 10" table saw this can be done in two passes, making the first cut then by flipping the board over on it's edge and making the second cut from the other side.

How do others make these sorts of cuts? What jig would make this cut safely?

I'm glad you included numbers in your question. It allows me to say that you mean "rip a board in half along it's thickness"

This operation is normally called resawing.

Since I own no power tools, and have little knowledge of them, I'll leave answering your (now clarified) question to others.

BugBear

 

[cusimar9]

Thanks bugbear, updated the question.

 

[Newbie_Neil]

Hi,

The safest way is to do it is with a bandsaw. However, when you're re-sawing that thickness you might just end up with two unusable pieces of timber.

Neil

 

[Woodmonkey]

Maximum depth of cut on a 10 inch table saw will not allow you to cut 200 mm (100mm each side). You need a bandsaw.

 

[wizard]

A 10” blade will only cut around 3” you need to cut just over 4”. I have a 14” saw with a riving knife shorter than the blade and a side mounted gaurd.

 

[cusimar9]

Maximum depth of cut on a 10 inch table saw will not allow you to cut 200 mm (100mm each side). You need a bandsaw.

Good point, lets say the boards are 170mm wide then

 

[RogerBoyle]

Bandsaw gets my vote its part and parcel of what it was designed for
However that said you could use a table saw cut through on one side and then turn it around
I don't recommend it etc. etc. but ........

 

[wizard]

If its a saw with the blade attached to the motor no

 

[Graham Orm]

Easiest way is to buy some 10mm thick boards. A band saw is the only way to do this with any accuracy, it has to be well set up, but will do the job. If you try using a table saw don't try and cut to the full depth of the blade in one pass, work up to full depth in three passes, less heat build up and kinder to the motor.

 

[Random Orbital Bob]

The truth is people are avoiding giving you a straight answer because its a horrible cut to do on a table saw. Dangerous to boot and likely to burn the timber. It is just about possible with the following caveats:

- obviously twice the blade height must be greater than the width you're cutting or it wont meet up in the middle.
- Use the method you suggested and cut it from either side but reference off the same face side (well planed flat).
- use a featherboard to push the stock close in to the fence so its not tempted to drift away from the fence
- use a low tpi ripping blade to avoid the blade stalling and burning. Preferably get a special thin kerf ripping blade
- wear safety everything and be very careful because if the blade grabs it and throws it back at you it's dangerous.
- don't overload the motor with an incorrect feed speed, go slowly and let the saw do the work and clear the kerf of swarf.

Do you not have a bandsaw?

The resultant pieces will be rough, not perfectly flat and likely scorched so will need planning. So you wont end up with anything like 10mm each. 8 at best I'd say and that's not accounting for the 3mm kerf. Its bordering on a waste of time if I'm honest.

 

[RogerS]

What all the others have said.

But as Grayorm has suggested buy in two boards that are 10mm thick. That way you know you won't have any bananas as I can almost guarantee that there is a good chance that after you have released the tension in your timber that the boards will twist and warp and bend and do all sorts of nasty things.

 

[cusimar9]

Sounds like it's not advisable then

I've found a wood yard about 30 minutes away that will resaw the wood for me, perhaps that's a trip worth making

No I don't have a bandsaw they're a bit out of my price range at the moment

Thanks for the advice

 

[Graham Orm]

Sounds like it's not advisable then

I've found a wood yard about 30 minutes away that will resaw the wood for me, perhaps that's a trip worth making

No I don't have a bandsaw they're a bit out of my price range at the moment

Thanks for the advice

As Roger said, expect distortion.

 

[skronk]

Its bordering on a waste of time if I'm honest.

Let him down gently now Bob......... :lol: :lol: :lol: :lol: :lol:

 

[flh801978]

If you need it doing i'm in S7 and I have a large bandsaw

Ian

 

[markturner]

Is there any way to avoid wood moving after you have cut it ? I have had several experiences of very well dried and good quality timber bending when cut down from larger stock. I generally buy stock at approx 50mm thick and 100 - 150mm wide. When cut down to smaller sections, despite the main piece being very carefully dimensioned first, my smaller sections will twist or bend after a day or so......very frustrating.

Cheers, Mark

 

[Paul Chapman]

Is there any way to avoid wood moving after you have cut it ? I have had several experiences of very well dried and good quality timber bending when cut down from larger stock. I generally buy stock at approx 50mm thick and 100 - 150mm wide. When cut down to smaller sections, despite the main piece being very carefully dimensioned first, my smaller sections will twist or bend after a day or so......very frustrating.

When reducing the thickness of a board, you really need to remove equal amounts from both sides if you want to ensure that it will remain stable. Doing it by re-sawing you are, in effect, removing it all from one side, which will often upset the balance. Better to start with a board nearer the thickness you want.

Cheers :wink:

Paul

 

[RogerS]

Is there any way to avoid wood moving after you have cut it ? I have had several experiences of very well dried and good quality timber bending when cut down from larger stock. I generally buy stock at approx 50mm thick and 100 - 150mm wide. When cut down to smaller sections, despite the main piece being very carefully dimensioned first, my smaller sections will twist or bend after a day or so......very frustrating.

When reducing the thickness of a board, you really need to remove equal amounts from both sides if you want to ensure that it will remain stable. Doing it by re-sawing you are, in effect, removing it all from one side, which will often upset the balance. Better to start with a board nearer the thickness you want.

Cheers :wink:

Paul

Absolutely bang on. I had a long interesting discussion with Peter Sefton a while back about this. I know it hurts to 'waste' wood but his view was - and I agree wholeheartedly with him - to take off from both sides as equally as possible. Even if you have a 2" board and want something 3/4" thick. The temptation is to rip it down the middle but that way lies disaster and much tearing out of hair and general anguish, teeth gnashing and swearing.

 

[Random Orbital Bob]

There is another way though I accept its not as purist as taking equal amounts from both sides. That's to dimension the timber and then use it in the project straight away ie before the wood sprites have had a chance to think about which tension they should be under. Once in context of the project the timber is often stiffened, fixed, glued etc in all manner of ways which significantly help to fix it so that it doesn't warp, bend, twist. Of course there is always a risk of splitting but there always is. So if the milling operation for a particularly at risk component can be delayed to just before assembly then that approach can work.

In addition, I've taken to clamping milled timber to a solid known flat surface like my work bench for days on end if there is an unavoidable gap between milling and assembly. I've outsmarted the sprites on two occasions with AWO where I cut several 2x2 legs out of a huge slab and immediately clamped them together and then to my bench after planing. I then went away for 4 days and came back to finish the project and they were fine. So my theory is don't let them bend in the first place. Once they're bent you're stuck but if you can take any measures to stop it I've found you usually get away with it.