Spiral Bit Questions

Hello, After hearing news that spiral bits when used correctly can greatly reduce tearout. I had to take a look. I would like if anyone who has used one with good results can post their techniques and PROPER usage clearly for me so I don't have a Maple Rocket launched across my garage. Diagrams would be most helpful! Thank you

Hello, After hearing news that spiral bits when used correctly can greatly reduce tearout. I had to take a look. I would like if anyone who has used one with good results can post their techniques and PROPER usage clearly for me so I don't have a Maple Rocket launched across my garage. Diagrams would be most helpful! Thank you

I tried my brand new spiral 2" up cut bit in the router table yesterday afternoon. I can tell you this from about 30 minutes worth of work. It allows you to route the full thickness of a body without raising your router. Other than that, you have to be VERY VERY careful. Sand your blank right down to your line so that you are taking only very little off with the router, or be very careful to take multiple light passes.

If you are used to using a router table, the same rules apply with the spiral bit. Don't expect to hog off huge amounts safely. Also, much has been written on this site about down hill routing. Approach that advice with EXTREME CAUTION. If you don't switch bits to a pattern bit and flip your body over for certain cuts, down hill routing involves climb routing in numerous places on your body. This means that you are moving your blank in the same direction as the rotation of the cutter head. I tried it yesterday, and promptly ruined a really nice hollowed mahogany blank with a highly figured maple top. The bit grabbed the blank on one of the climb cuts and threw it right out the garage door onto the aggregate driveway.:mad:

Bottom line. The spiral bit is nice, but definitely do not approach it with the idea that it will eliminate the need to intelligently complete the job safely and in a manner that will reduce the chance of tear out. I can tell you that it can cause massive tearout just like any other bit. Also, because of the 2" cutting length, it will grab your blank with much more force than you are likely used to in a router set up. I think the single best thing that you can do to reduce your chance of tear out, is to sand your body blank right to the line, so that you are removing very little material.

See hearing the part about your body flying is what has me thinking twice , I feel maybe I should just use a shorter flush cut bit with the body and take small amounts off at a time less than a quarter inch , I think that would be the safest way considering im inexperienced.

Oh Cap,

Sorry to hear about this. I had the same thing happen to me in this years Challenge build. The spiral bit is a great tool but when purchasing, no one tells you about it's quirks and they are not apparent. The pros like it because it can leave a glass smooth edge not requiring finish sanding. I get that. The key is to research it first. I'm almost thinking that it should be a warning sticky at the top of the DIY thread it's that important. It's probably the one tool that can do more large scale damage quicker than any other when used improperly.

Rob

Here is one of my threads with a full detail of pictures and videos utilizing this 2" spiral bit. (http://www.tdpri.com/forum/tele-home-depot/293920-new-toys.html)

Thanks Colt!

I'll spend time there today as I'm not giving up on this tool.

Rob

Oh Cap,

Sorry to hear about this. I had the same thing happen to me in this years Challenge build. The spiral bit is a great tool but when purchasing, no one tells you about it's quirks and they are not apparent. The pros like it because it can leave a glass smooth edge not requiring finish sanding. I get that. The key is to research it first. I'm almost thinking that it should be a warning sticky at the top of the DIY thread it's that important. It's probably the one tool that can do more large scale damage quicker than any other when used improperly.All power tools can be dangerous, but I think a Table Saw has more potential for the worst damage.

Rob

I think the key is understanding how to use a router in general. For those of us who grew up with wood working tools, we assume a lot of things are simple common sense, but to the novice or average guy, not so much.

I tried my brand new spiral 2" up cut bit in the router table yesterday afternoon. I can tell you this from about 30 minutes worth of work. It allows you to route the full thickness of a body without raising your router. Other than that, you have to be VERY VERY careful. Sand your blank right down to your line so that you are taking only very little off with the router, or be very careful to take multiple light passes.

If you are used to using a router table, the same rules apply with the spiral bit. Don't expect to hog off huge amounts safely. Also, much has been written on this site about down hill routing. Approach that advice with EXTREME CAUTION. If you don't switch bits to a pattern bit and flip your body over for certain cuts, down hill routing involves climb routing in numerous places on your body. This means that you are moving your blank in the same direction as the rotation of the cutter head. I tried it yesterday, and promptly ruined a really nice hollowed mahogany blank with a highly figured maple top. The bit grabbed the blank on one of the climb cuts and threw it right out the garage door onto the aggregate driveway.:mad:

Bottom line. The spiral bit is nice, but definitely do not approach it with the idea that it will eliminate the need to intelligently complete the job safely and in a manner that will reduce the chance of tear out. I can tell you that it can cause massive tearout just like any other bit. Also, because of the 2" cutting length, it will grab your blank with much more force than you are likely used to in a router set up. I think the single best thing that you can do to reduce your chance of tear out, is to sand your body blank right to the line, so that you are removing very little material.

I know folks like Jack Wells get great results down hill routing, But I have never been able to get downhill routing to work for me.

Im still sitting here saying its either I get the spiral or a 1/2 inch diameter X 1 inch cutting length standard bit . I cant tell what I should get.

If you don't have either bit, start with the 1/2" x 1" top bearing pattern bit. You can use it for other operations like neck pockets & PU's. You can also shape a body with it. Once you're comfortable with it and router use in general, buy the spiral bit.

I think the key is understanding how to use a router in general. For those of us who grew up with wood working tools, we assume a lot of things are simple common sense, but to the novice or average guy, not so much.

Actually Colt I disagree with you here as you can route in either direction safely with straight cut router bits which many of us grew up with. I had never heard of a spiral bit until becoming member of this forum. It would seem "simple common sense " that the same would be true for the spiral bit until the unfortunate truth was discovered.

Rob

I had never heard of a spiral bit until becoming member of this forum.
Rob

Either did I till Preeb introduced them to the forum back in 09. Seems he is always one step ahead of us mortals.

Either did I till Preeb introduced them to the forum back in 09. Seems he is always one step ahead of us mortals.

Is that vintage correct? :mrgreen:

I think the key is understanding how to use a router in general. For those of us who grew up with wood working tools, we assume a lot of things are simple common sense, but to the novice or average guy, not so much.

That is the part that makes me really mad at myself. I've been building custom furniture since about 1990. I've been using spiral cutters in the router since the mid 90's. I had read about the downhill routing technique and thought "I'll try it", even though I knew it would be potentially hazardous in spots. What really makes me mad, is that my experience told me I should "approach with caution" but I went ahead and did it anyway. Won't ever do it again.

I think the real lesson learned is that there is no free lunch. The time you save in running your blank through in one pass is offset by the extra time you need to take sanding close to the line.

Downhill routing is used so that the straight cutting bit won't "jam" into grain ends and tear it out. Spiral bits' cutting edge(s) are always in contact with the wood and instead of "chiseling" the wood, they shear it, thus, grain direction is not important. The spiral bit cuts cleanly across all grain orientations. Thus no need to even try downhill routing.

Although I have done downhill routing before, my reading and experience made me well aware of how hazardous it is, so I approach it with aversion, and extreme caution. The spiral bit removes the need for me to even consider downhill routing, to me, worth the cost. That, and the total absence of any layered look on the edge of a body slab, plus a very clean, smooth edge.

As for ANY pattern routing work of this type, it is important to remove wood as closely to the finished line as possible before introducing it to the router, spiral or straight bit.

Colt's introduction/tutorial above is a very good information source--convinced me this is the bit I needed, and I have not regretted it for one second.

Downhill routing is used so that the straight cutting bit won't "jam" into grain ends and tear it out. Spiral bits' cutting edge(s) are always in contact with the wood and instead of "chiseling" the wood, they shear it, thus, grain direction is not important. The spiral bit cuts cleanly across all grain orientations. Thus no need to even try downhill routing.

Although I have done downhill routing before, my reading and experience made me well aware of how hazardous it is, so I approach it with aversion, and extreme caution. The spiral bit removes the need for me to even consider downhill routing, to me, worth the cost. That, and the total absence of any layered look on the edge of a body slab, plus a very clean, smooth edge.

As for ANY pattern routing work of this type, it is important to remove wood as closely to the finished line as possible before introducing it to the router, spiral or straight bit.

Colt's introduction/tutorial above is a very good information source--convinced me this is the bit I needed, and I have not regretted it for one second.

Well said Rick , I agree 100%

So should I use this bit or not? Because it seems like Because of my inexperience with a router I should go with the standard bit.

So should I use this bit or not? Because it seems like Because of my inexperience with a router I should go with the standard bit.

I think you answered your own question , IMO the 2" x 1/2" spiral bit is not a good choice for inexperience , you seem very cautious/hesitant about it , which is good , that means you are thinking , confidence or knowing you can use a certain tool properly and safely plays a huge part in this , if you don't feel ready to use it don't use it , only you will know or feel when you are ready , and that comes with experience .

So should I use this bit or not? Because it seems like Because of my inexperience with a router I should go with the standard bit.
If at this point your still not sure, then go with a regular old strait bit. Once you feel more comfortable with your tool, then move on up. Besides, your going to want a regular template bit for other things anyways, so its not like your throwing money away.

I've got one, and frankly, I'm afraid of it now. I've chunked two blanks across the shop. I simply don't have the knowledge to use the thing properly yet. After two mishaps, two ruined blanks, and still being quite fond of having all my digits, I'm taking an even more cautious approach to this thing. I need more knowledge before I try again.

Downhill routing is used so that the straight cutting bit won't "jam" into grain ends and tear it out. Spiral bits' cutting edge(s) are always in contact with the wood and instead of "chiseling" the wood, they shear it, thus, grain direction is not important. The spiral bit cuts cleanly across all grain orientations. Thus no need to even try downhill routing.

Although I have done downhill routing before, my reading and experience made me well aware of how hazardous it is, so I approach it with aversion, and extreme caution. The spiral bit removes the need for me to even consider downhill routing, to me, worth the cost. That, and the total absence of any layered look on the edge of a body slab, plus a very clean, smooth edge.

As for ANY pattern routing work of this type, it is important to remove wood as closely to the finished line as possible before introducing it to the router, spiral or straight bit.

Colt's introduction/tutorial above is a very good information source--convinced me this is the bit I needed, and I have not regretted it for one second.


I think you've got this backwards. Downhill routing is the easy, good routing technique. Uphill routing or climb cutting is the technique that gives so many people trouble. If you go around an entire body in one direction you will have no choice but to climb cut, every downhill cut has an uphill cut on both sides of it. I've been using a 2 " straight bit with the bearing on both ends for a while now, with good success. I haven't mentioned it here since I first bought the bit because unless you sand ON the line, as with a spiral bit, you'll eventually run into problems. I'm getting tired of all the "watching the line" sanding on the ROSS so I just bought a set of Robo-sanders that Preeb recommended a while back. They come tomorrow, I'll let you know.

This is a very good thread to read http://www.tdpri.com/forum/tele-home-depot/179737-tearout.html

I've got one, and frankly, I'm afraid of it now. I've chunked two blanks across the shop. I simply don't have the knowledge to use the thing properly yet. After two mishaps, two ruined blanks, and still being quite fond of having all my digits, I'm taking an even more cautious approach to this thing. I need more knowledge before I try again.

It appears to me as if you are trying to take to much of a bite. Any router bit will grab and maybe throw the stock if you try to hog out too much at one time. I have over a dozen spiral bits in various sizes and use them for about any routing I do since I first used one.

I buy most of my spiral bits from Onsrud because they are sharper and hold up better than most bits. They also have specialty bits for about any kind of routing one will ever do. They (Onsrud) have a spiral finishing bit and a spiral bit for routing acrylics that do a fantastic job.

This is a very good thread to read http://www.tdpri.com/forum/tele-home-depot/179737-tearout.html

Wow, I forgot all about that thread. I also forgot that I already have a Robo-sander. I put it away because my old drill press didn't have enough power to keep the thing spinning when I applied pressure. I'm going to need some luck finding it in the disaster area/shop. I just bought the 3 pack of Robo-sanders & now I have a nice big floor model drill press to spin them on. We'll see...

If you do not already have a rubber cleaning stick for sandpaper you will *definitely* need one for the Robo Sander. Do not wait until you have (waaaay too quickly) ruined your sanding sleeves to get the cleaning stick. Please, learn from my earlier ignorance.

I think you've got this backwards. Downhill routing is the easy, good routing technique. Uphill routing or climb cutting is the technique that gives so many people trouble. If you go around an entire body in one direction you will have no choice but to climb cut, every downhill cut has an uphill cut on both sides of it. I've been using a 2 " straight bit with the bearing on both ends for a while now, with good success. I haven't mentioned it here since I first bought the bit because unless you sand ON the line, as with a spiral bit, you'll eventually run into problems. I'm getting tired of all the "watching the line" sanding on the ROSS so I just bought a set of Robo-sanders that Preeb recommended a while back. They come tomorrow, I'll let you know.

Climb routing has nothing at all to do with whether you are going "uphill" or "downhill". It describes the action of moving your work piece in the same direction that the moving cutter head is spinning. It is so named because the router bit will want to climb right along the edge of your work piece. Sometimes very quickly and very violently.

For safe work with a router, you want to move your work piece against the the rotation of the cutter. There are times when you may want to "climb" cut, but you have to know the risk and you have to take very light cuts. Climb routing should be avoided by folks who have never used a router. Basically, if you don't know what it is, you shouldn't be doing it. That's the irony. How do you know what to avoid, when you don't know what it is?:smile:

When using a spiral bit (or a straight flute bit) there is no rule that says your bearing must come in contact with your template on the first pass. If you haven't cut as close to the line as you would when using a planer, it's perfectly safe to shave a bit off each time around the body.

Might take 4 or 5 times around the work piece before the last pass has the bearing touching the template. This is realising the tool's limitations and working with this limit - not against it. Only a fool thinks they control a powertool ... you are only ever its guide. Don't disrespect it or ask it to do too much and it'll thank you for your patience and gentle approach by leaving a surface that requires much less work. And it'll stay sharper, longer because overheating is the death of a sharp edge.

Jam a piece of wood at it and it'll throw it across the workshop in disgust.

Climb routing has nothing at all to do with whether you are going "uphill" or "downhill". It describes the action of moving your work piece in the same direction that the moving cutter head is spinning. It is so named because the router bit will want to climb right along the edge of your work piece. Sometimes very quickly and very violently.

For safe work with a router, you want to move your work piece against the the rotation of the cutter. There are times when you may want to "climb" cut, but you have to know the risk and you have to take very light cuts. Climb routing should be avoided by folks who have never used a router. Basically, if you don't know what it is, you shouldn't be doing it. That's the irony. How do you know what to avoid, when you don't know what it is?:smile:

You're right, I should have differentiated between the two. Both are techniques I don't use, I kind of think of them as one. I've lost good wood using them in the past, not anymore.