Thickness of MDF Templates

[TheNewSteveH]

I have come to the conclusion that Ron Kirn is a genius, and I am also aware that I know virtually nothing about making guitars, but I will question his methods anyway. He recommends 3/4" MDF for templates. I made a template today, and then later it occurred to me that in order to use it, I would have to get my router bits to rise way out of the table. I guess I'd have to leave a lot of the shafts hanging out, too.

Is 3/4" really needed? The router bearings are only around 3/16" tall, so I would think anything over 1/4" would be pretty easy to use, and it would be somewhat easier to make templates.

[Colt W. Knight]

You should only be routing about a 1/4" of material. So, you need the extra height of the template to work your way down. If you tried to do 1" or the full 1 3/4" at one time, you would have some major router bit chatter, and tear out. This will ruin your day.

[LeroyBlues]

Originally Posted by Colt W. Knight

You should only be routing about a 1/4" of material. So, you need the extra height of the template to work your way down. If you tried to do 1" or the full 1 3/4" at one time, you would have some major router bit chatter, and tear out. This will ruin your day.

What he said.

[TheNewSteveH]

Thanks for the info about chatter.

It looks like I am paying the price for forgetting what little I learned about woodworking.

[4string]

It is possible to rout the entire 1 3/4" in a single pass without tear-out, chatter, or even burn marks if using the correct bit for this. Preeb has used and recommended this bit, so I tried one. I have done two bodies so far; Alder and Douglas Fir. I got zero tear-out on either.

The bit is a solid carbide spiral up-cut flush trim bit (bottom bearing) 1/2" shaft and diameter, 2" cut length. These bits are expensive, but should last a long time. The reason these bits don't have tear-out problems is due to the spiral cutting flutes slicing the wood on an angle.

I have done it both ways. Since getting the spiral bit, I will continue to use it exclusively until "something happens", at which time (if ever) I will re-assess single pass body routing.

I have already learned this much: with the spiral bit it is absolutely necessary to rout in the correct direction of leading the cutting edges upwards into the cut ie: NO 'downhill routing' that is often discussed on this forum of moving in both directions. When this bit hooks up, "tear-out" doesn't seem like a strong enough term to use. Maybe "amputation by Great White" would be better...

[Colt W. Knight]

4 string is correct, but that expensive bit doesn't work for the pickup and control cavities.

[4string]

Originally Posted by Colt W. Knight

4 string is correct, but that expensive bit doesn't work for the pickup and control cavities.

+1. It is a bit dedicated to body shape routing only, and at $75 on sale or $119 list price, not the most affordable. Jack Wells gave you good advice when he said a 1/2" diameter, 1" cut length top-bearing bit is all needed to rout an entire solid body bolt-on neck guitar. And a round-over bit.

['59_Standard]

Originally Posted by 4string

It is possible to rout the entire 1 3/4" in a single pass without tear-out, chatter, or even burn marks if using the correct bit for this. Preeb has used and recommended this bit, so I tried one. I have done two bodies so far; Alder and Douglas Fir. I got zero tear-out on either.

The bit is a solid carbide spiral up-cut flush trim bit (bottom bearing) 1/2" shaft and diameter, 2" cut length. These bits are expensive, but should last a long time. The reason these bits don't have tear-out problems is due to the spiral cutting flutes slicing the wood on an angle.

I have done it both ways. Since getting the spiral bit, I will continue to use it exclusively until "something happens", at which time (if ever) I will re-assess single pass body routing.

I have already learned this much: with the spiral bit it is absolutely necessary to rout in the correct direction of leading the cutting edges upwards into the cut ie: NO 'downhill routing' that is often discussed on this forum of moving in both directions. When this bit hooks up, "tear-out" doesn't seem like a strong enough term to use. Maybe "amputation by Great White" would be better...

Bear-in-mind, Preeb/Gil is cutting his body right down to the line and is only taking the merest, wispy, shaving. In effect, he's near scraping the surface. There's nothing for the bit to really grip onto. So its a lot safer.

Not trying to be a killjoy on the spiral bit - I just have concerns of some newbie thinking a Spiral is like a normal bit in use. Its not. I'm very wary of using a spiral bit having read Pat Warners comments/dangers - which I'd posted links on before. The Woocraft link has a safety mention on the bottom of the page. Even, Warner, is wary of using them.

My old post

[4string]

Originally Posted by '59_Standard

Bear-in-mind, Preeb/Gil is cutting his body right down to the line and is only taking the merest, wispy, shaving. In effect, he's near scraping the surface. There's nothing for the bit to really grip onto. So its a lot safer.

Not trying to be a killjoy on the spiral bit - I just have concerns of some newbie thinking a Spiral is like a normal bit in use. Its not. I'm very wary of using a spiral bit having read Pat Warners comments/dangers - which I'd posted links on before. The Woocraft link has a safety mention on the bottom of the page. Even, Warner, is wary of using them.

My old post

I hear you. I can't recommend a spiral pattern bit for the novice.


It is a high horsepower router table ONLY bit that cuts the time to shape rout a body down to under 5 minutes with a cut as smooth as having your barber give you a shave with a straight blade razor after the hot towel and hand whipped shaving cream treatment....

It's of prime importance to know what you are doing when routing. But let's face it, the easiest and safest routing task can be deadly when caught off-guard. It is of prime importance to know just where your hands will be headed if the work unexpectedly gets bucked or thrown. Understanding the dynamics of what is happening at the point of cut is the key to safely handling any router operation.

I have been professionally handling routers for decades on materials other than wood. The longer I have done it, the more appreciation I have gained for the need to be aware when the safety margin is minimal, and taking the time to set-up a less dangerous routing approach albeit losing time over some quickie zip-zip method where one false move and there goes some fingers flying or I now have a 1/2 by 2" deep dado through my thigh etc.

With that said, I would still think that most woodworkers (and other material fabricators too) can appreciate a tool that just plain-and-simple works better. I have a 5/8 by 2" slant flute flush-cut bit also. That bit is WAY scarier to me than the spiral bit because it is way more likely to hook-up (mega tear-out) and fling the body off the table. An up-cut spiral bit pulls the workpiece down on the table. There's no lift. I don't know what they were talking about unless they were referring to a down-cut spiral bit. No gracias to one of those.

You have taken the time to research the dangers of spiral bits. That is the kind of knowledge needed to make you an eligible candidate to try one out. You will undoubtably not suffer any accidents as a result of your cautiousness. It is the 'I don't need no safety lecture' type of guy who is destined for the trips to the hospital...

[Nick JD]

If you're a professional guitar builder - or plan to be - do yourself a favour and make a $3000 CNC machine. That's what you'll spend on all the other tools it replaces . And it's much safer, quicker and neater.

If you're making a few guitars in the shed - buy a 1/2" by 1" pattern following bit.

[pavel]

As 4string points out, the linked articles seem to be a bit confused -- an up-cut spiral used on a router table will be pulling the piece to the table, not pushing it up.

I'm no large scale production but the spiral bits are definitely the way to go, in my experience. You do need a router table, prepare the piece to reduce the amount of removed material and be safe, of course, but the results are flawless.
It only takes a couple of screwed up nice body blanks to make up for the price of the bit.

As for the thickness of templates, I find that especially for neck templates the 3/4" MDF is great because it flexes less than the thinner stuff.

[Ronkirn]

You should only be routing about a 1/4" of material. So, you need the extra height of the template to work your way down. If you tried to do 1" or the full 1 3/4" at one time, you would have some major router bit chatter, and tear out. This will ruin your day.

What he said . . . again... and what I said..... the instructions are intended for the home workshop, or kitchen as the case may be, and someone that will not be buying a few hundred bux worth of router bits....

With a template 3/4 inches thick, you can make a $14.00 1/2 inch d by 1 in cutting length do what it would take 3 bits to do with templates 1/4 inch thick..

and by taking 3/4 of the cut around the periphery then flipping it and doing it again, you can get a 22 buck bit to do what Marty's 120.00 sweet heart does... with the hundred bux...you saved..... you can take the little lady out to Ruth's Chris Steak House.... before she sees what you have done to the kitchen table...

There's reason to my madness.

Ron

[Colt W. Knight]

Originally Posted by '59_Standard

Bear-in-mind, Preeb/Gil is cutting his body right down to the line and is only taking the merest, wispy, shaving. In effect, he's near scraping the surface. There's nothing for the bit to really grip onto. So its a lot safer.

Not trying to be a killjoy on the spiral bit - I just have concerns of some newbie thinking a Spiral is like a normal bit in use. Its not. I'm very wary of using a spiral bit having read Pat Warners comments/dangers - which I'd posted links on before. The Woocraft link has a safety mention on the bottom of the page. Even, Warner, is wary of using them.

My old post

If you chuck that spiral bit up in a 3 1/2 hp router on a table or a nice shaper, you can take a lot of material down.

However, it's best to follow Ron's directions in his pamphlet/book. It will not lead you astray. Thanks for all the great info Ron!

[Ronkirn]

I just have concerns of some newbie thinking a Spiral is like a normal bit in use

good point..... Back when I was selling the templates (i'm Not, Pierre my son 'n law is...) I would routinely "preach" safety.. and self awareness...

Still today, I get questions from guys that have bought them that suggest that they have no business using any tool that gets plugged in, or any with a sharp edge...

You have to be aware of what you can and cannot do. If you are "tool challenged" ... get the hell away from a 2 HP router spinning a razor blade at 25000 RPM..

Getting your fingers sewed up by an internist in the Emergency Room, costs a hellova lot more than a new guitar does...

Just know what you're getting into and if you are not comfortable in a fully equipped workshop, find a friend that is, and get 'im to help ya.

Ron

['59_Standard]

Ron, I don't want to appear as as arse kisser/licker etc, but thanks for your useful/helpful advice posted on this here forum. As well as Mr Wells, Colt, and any others I've failed to mention... Much appreciated fellas.

And if anyone can point me to Ron's Fret level thread I'd be mighty obliged - I usually find no issue using the search function, but that thread eludes me.

[jbmando]

Originally Posted by '59_Standard

Ron, I don't want to appear as as arse kisser/licker etc, but thanks for your useful/helpful advice posted on this here forum. As well as Mr Wells, Colt, and any others I've failed to mention... Much appreciated fellas.

And if anyone can point me to Ron's Fret level thread I'd be mighty obliged - I usually find no issue using the search function, but that thread eludes me.

Here

['59_Standard]

Thank you very much, jb - not sure why they didn't come up under a "fret" search.

[4string]

Originally Posted by pavel

As 4string points out, the linked articles seem to be a bit confused -- an up-cut spiral used on a router table will be pulling the piece to the table, not pushing it up.

I'm no large scale production but the spiral bits are definitely the way to go, in my experience. You do need a router table, prepare the piece to reduce the amount of removed material and be safe, of course, but the results are flawless.
It only takes a couple of screwed up nice body blanks to make up for the price of the bit.

+1. I just started guitar building and I'm working on my 2nd from scratch body. I also have a "crash-test dummy" body out of doug fir I do all the testing on 1st before proceeding with the real deal. So that adds up to a whole 3 bodies to date.

I have no plans to mega-produce, but it is nice to know I have gotten equipment to make that possible. The attractor, as far as the spiral bit, is not the speed aspect. The clean cut is. I have no problem dropping coin on any tool that can/will: (in order of importance)

1) work better/superior result
2) last longer
3) speed-up the process

(What's really funny is that for my job this list is exactly reversed...)

Any tool that can do all 3 is worth it's weight in gold and only a fool would buy anything else. I would rather be eating at that restaurant with Ron then spending the money on another expensive body blank or buying bondo by the gallon.





On a side note, Ron gets to the restaurant his way; he knows the wood so well he probably wouldn't get tear-out chopping a tree down with an axe. It would probably look like it was felled with a Star Wars Laser Saber....

Com'on Ron, face the facts. All you gotta do is look at it, snap yer fingers twice, and it's done purfect. Us mere mortals need all the help we can buy...


(Seriously, Ron has the best advise on the planet. Listen to him and ignore everyone else.)






It's a shame there are no top-bearing spiral bits. That would have to be the ideal; step-cutting with a spiral bit. Say good-bye to tear-out forever.






And I'm a hopeless "Tool Junkie"...

I used to have a hard time figuring out what everybody was laughing at on the Tim Allen show. 'Tool Time' was a serious show (wasn't it...)

[Ronkirn]

only one snap required....

rk

[TheNewSteveH]

Don't give your hard-earned cash to Ruth's Chris until you've tried aging your own rib eyes at home. If you think a homemade guitar is good, wait until you've tried home-aged prime beef.

I had to digress and preach. This is a topic which is close to my heart.