Thread: Stopping tear out

Originally Posted by Strungout

Hi

I am (trying) making a guitar neck,and when I was routing the end grain (carefully) on the Triton router table it tore out a big chunk-Actually it split a piece off it.

I am using a new 12mm CMT template bit and was feeding the timber against the rotation -IE the bit was pushing against the wood .(is this right?)

How can I do this without it happening again.It just seem to "grab" it in the ends.

It worked OK on the straight sides but not on the ends.

I am using rock maple. :confused:

Using a larger cutter will help
It will also depend on how much you are trying to remove at one time.
The thicker the material the greater the strain on the cutter and the greater the chance of tear out
My suggestion would be to use smaller cuts with the aid of the template guide and a simple straight cutter.
Best of luck
Tom

Glad to see I'm not alone!

Moving against the rotation of the router is necessary, but on some timbers it is also possible to catch the end grain when you are doing this.

I know!! I destroyed a few pieces of old dry silky oak and scared my fingers (and me) doing exactly what you are doing...it doesn't always work the way the magazine pictures show!

It will help if you turn the piece over to go "with the grain" at all times, (still going "against" the rotation of the bit) especially when you are coming up the neck to the curvy bits.

Cheers,

P

Hi

Try doing a little snip on the end grain on the out feed side first, or, put a block of wood on the out feed side so it is tight against the timber.
This will illiminate ripping the timber grain.

Al

As Ozwinner has already stated. Try an offcut against the outfeed side. Let the bit cut into the offcut before you remove the piece to make sure you get a completed cut. Then if you get tearout it will be in the offcut not your project.

Greg, Oz,

You guys are right when routing a straight line (or whatever) but when you have a complex curve I (say an "S") I can't see a way of doing that other than inverting the piece and going "with the grain".

Anyone care to draw a diagram?

P

Originally Posted by bitingmidge

You guys are right when routing a straight line (or whatever) but when you have a complex curve I (say an "S") I can't see a way of doing that other than inverting the piece and going "with the grain".

Anyone care to draw a diagram?

P

How about this:


Assuming you are using a table router (and, for example, using a template with flush trimming bit) then section A will be straightforward but section B will be prone to break-out, helped, but not necessarily solved, by having a piece of sacrifical wood at C.

If you are using a hand-held router and template guide then you will be going the other direction and B will be OK but A will be prone to break-out.

How to get around the problem:

1) As midge suggests, you could turn the piece over half-way. With a symmetrical shape this means you only ned to make the template for half the shape, but you have two positioning set-ups. For non-symmetrical shapes you need two templates plus all care between set-ups to correctly line up the join line between shapes.

2) A variation on this is to use one template fixed above the workpiece and a flush-trimming bit for A, then turn the template and workpiece over and use a template following bit (flush trimming bit with the bearing at the base of the cutter) for B. For this task the template stays attached to the workpiece at all times, and arguably, changing bits is easier than repositioning the workpiece on another or the same template.

3) Alternatively: Don't try and *trim* the shape with the router, but cut it using a hand-held router, template guide/copy ring and straight cutter from the top .... cutting/plunging only a few mm at a time. The only problem with breakout would be on the left side, and a piece of sacrifical wood here would work well.

Whilst break-out wouldn't be a problem with method 3), you would still be going against the grain for the second half of the cut, and, unlike with methods 1) and 2) the finished cut on this side would be somewhat rough ... needing some cleanup with sand paper.

Q: How would the professionals do this? A: not with a router. For one-off or small production runs they would almost certainly cut it as close as possible with a band saw or similar then use an oscillating spindle sander or similar to finish it off.

Qw

Thanks QldWoodie,

That's exactly where I was coming from! I hadn't thought about doing the cut with a router, but have solved the problem in the past with the bandsaw/sander routine.

I think this is one of those situations where the pics in the books don't reflect the type of timber we work with!!

Regards,

P

QLDWODIE,

thanks a lot for your detailed reply.I think I might have a play around with some scrap -like suggested but I am thinking of routing the sides and sanding the ends like you say.

Over in the USA I see they sell a "ROBO SANDER" which is a drum/spindle sander that fits into a drill and has a guide on it for going around templates.

Does anybody know if they are available in Australia ?

Thanks

Greg

Hi Greg

Can't help you with the Robo Sander but would love to see a picture of the axe when you finish it.

Regards
Rick

Strungout, I cut my blank neck across the end with a bandsaw then do final shaping with a sander for strat and tele style necks. I route the sides with a template and hand held router and appropriate cutter. I have a triton router table and would not try what you have on it for the same reason. Have fun with the suggestions.

regards Mike

Originally Posted by Strungout

Over in the USA I see they sell a "ROBO SANDER" which is a drum/spindle sander that fits into a drill and has a guide on it for going around templates.

Does anybody know if they are available in Australia ?

Hi Greg
I don't know about the Robo sander either, but it wouldn't be very difficult to make your own. All that you would need to do is attach a small circle of something to the bottom (or top) of the drum sander in the drill press and use that as a guide. It really wouldn't even matter if it was just a piece of turned hardwood or a large washer so long as it follows the pattern

Yes I should have done exactly what you are saying Mick,and the second attempt I will!

The whole neck came out really good apart from the bloody headstock.I kind of tried to shape it to try to make some use of it but its not going to be any good.

I have started to make up a template sander like Bob suggested so that might go OK on the next attempt.

How many guitars have you made and what kind of timber have you used for the body and neck.

Its a great hobby!

Cheers

Greg

[QUOTE=lucky_rick]Hi Greg

Can't help you with the Robo Sander but would love to see a picture of the axe when you finish it.

Thanks Rick, When I finish it I will post a picture but its kind of taken me about 6 months to get to this stage(neck & body cut out) so it might not be for a while yet .

Do you play?

Regards

Greg

Hi,
The Robo sander can be purchased from WOODCRAFT. Go to....................
http://www.woodcraft.com/Woodcraft/p...324EBA3E61D1BE