# Cutting fancy edges in both wood and metal



## Grimm (Oct 5, 2009)

I'm currently working on a project that uses both wood and metal and I wanted to put some fancy edging on some of the parts. I have a router table but it's big and clunky and the bits for it are very expensive and the mini bits are hard to find. I also wasn't sure how well it could handle small metal parts, if at all? I have a mill and was looking at some great edging that people were doing with a custom fly-cutters, but again wasn't sure if they could handle cutting wood? I was thinking of purchasing a set of these fly-cutters here:

http://littlemachineshop.com/products/product_view.php?ProductID=3094&category=1963256902

And hand shape the bits in the shapes that I need. Anyone have any kind of experience with this and would it handle wood (that would be hardwoods) well? I was thinking I could crank the mill up as fast as it could go and use a couple of sacrificial wood pieces on each end of the part I was cutting to help stop any splintering. Or maybe there is a better way? Thanks,









Jason


----------



## xo18thfa (Jan 2, 2008)

Posted By Grimm on 23 Mar 2011 07:22 PM 
I'm currently working on a project that uses both wood and metal and I wanted to put some fancy edging on some of the parts. I have a router table but it's big and clunky and the bits for it are very expensive and the mini bits are hard to find. I also wasn't sure how well it could handle small metal parts, if at all? I have a mill and was looking at some great edging that people were doing with a custom fly-cutters, but again wasn't sure if they could handle cutting wood? I was thinking of purchasing a set of these fly-cutters here:

http://littlemachineshop.com/products/product_view.php?ProductID=3094&category=1963256902

And hand shape the bits in the shapes that I need. Anyone have any kind of experience with this and would it handle wood (that would be hardwoods) well? I was thinking I could crank the mill up as fast as it could go and use a couple of sacrificial wood pieces on each end of the part I was cutting to help stop any splintering. Or maybe there is a better way? Thanks,









Jason 


DO NOT run metal over a router table DO NOT. A router will kick that metal bad at you as fast as a bullet.

Profiled bit in a fly cutter should work fine. Take several passes, light cuts at a time. If the mill is not rock solid rigid, it may chatter on a deep cut. Run slow speed.

An ordinary Dremel with the 1" diameter (or so) abrasive wheel works very well cutting and shaping HHS blanks.


----------



## Dwight Ennis (Jan 2, 2008)

I agree completely with Bob on trying to use a router and/or router table on metal. 

From my own experience, the milling machines I own don't produce high enough rpm's to use on wood - not and get a clean cut at least. To some degree it depends upon the hardness of the wood being worked as well, but I haven't had great results. 

It's hard to advse without knowing more specifically what you're trying to achieve, but here are a couple of thoughts... 

End mills are available that will cut fillets (ball end mills) and rounds (radiusing end mills), and with some care and multiple passes could probably be used in combination to cut an ogee curve or similar in metal. In his "Building the Climax" book, Kozo describes the process for making a custom cutter for milling gear teeth. I would think that his process could be adapted to make custom cutters for edging metal. As a fly cutter holds the cutting tool at a downward angle, you would have to keep that in mind in shaping the cutting tool if you go that route. You might also consider using a slitting saw to hog out the rough cut, then coming back with ball or radiusing end mill (or fly cutter with custom tool) and do the finishing work.


----------



## Grimm (Oct 5, 2009)

Thanks Bob, Dwight,

I had thought as much, that's why I wanted to check first just to be on the safe side.







That is a good point about the fly cutters holding the bit at an angle. I wasn't able to find a fly-cutter that holds the bit horizontally, at least one with a mt3 arbor. I did find this at LMS.

http://littlemachineshop.com/products/product_view.php?ProductID=2393&category=2

It would be fairly easy to mill this into a horizontal fly-cutter I think. My goal is to limit my tooling (costs) and having one tool to cut both wood and metal would be awesome. It's too bad to hear that you didn't get a good finish on the wood. I have a mini mill that goes up to 2500 RPM but I don't know if that would be fast enough? I think my router goes up to 15,000 RPM if I remember correctly. At least it sounds like it does.







I will have to give it a try, at least with the wood it's easy to hand sand the finish and make it presentable. 

Jason


----------



## Dwight Ennis (Jan 2, 2008)

Jason - here's a section with photos from my CP-173 Builder's Log. A few photos are worth a thousand words.









I needed to make a form around which to shape the wagon-top transition piece of my boiler jacket. From my Builder's Log...

*This is a somewhat strangely shaped piece - a conic section, or slice through a cone diagonally. It starts parallel with the boiler center-line on the bottom, and the angle gradually and continuously increases to the top, then decreases back to the bottom. After thinking about it for a while, I decided the best way to make it was to create a former and support structure out of hardwood. As wood was originally used for boiler lagging, I figured I could also leave the support structure in place under the transition piece sheet metal.*

*I laid everything out in AutoCAD and wrote the g-code for the front and rear pieces which would constitute the correct angles - a series of 1/16" deep circular cuts, each larger than the preceding one and all tangent at the bottom. I then cut them on the CNC milling machine. *

*My first attempt wasn't entirely successful because I chose the wrong wood - I used red oak, which doesn't have a tight enough grain structure. It splintered too much for my taste and looked crappy. A quick call to Bob Sorenson resulted in a recommendation to use maple. The second try using maple worked out good (a big thanks Bob!!!).*

*Here's the basic support structure...*






































For my purposes, this worked out well as it provided the profile I needed to bend metal sheet around, and it would be hidden anyway. But as you can see from the photos, the milled cuts were far from clean, and LOTS of sanding would be required to clean them up enough to be presentable if they were visible edges.

I'm no expert on woodworking (not of Bob's caliber anyway), so my guess that the milling machine just didn't have the required rpm's for wood is just that - an educated guess. But as you said, routers made for woodworking have much higher rpm's, and as far as I can see, that's the basic difference between routers and milling machines other than portability, precision, etc. But in terms of their basic operating principle of a rotating cutting tool removing material, they are essentially the same other than spindle speed.

Hope this helps to clarify things.


----------



## Grimm (Oct 5, 2009)

Thanks Dwight,

The inside edges look nice, but I see what you mean with the outside. I did some research on the use of fly-cutters on wood and found some interesting information. It appears that many people do use them for cutting wood, at fairly low RPMs as well (600 to 1000). The big difference is how you shape the tool bit. Which make sense in hindsight. The wood cutting bit needs to be shaped much like a chisel and be very sharp. I went ahead and bought the blank arbor and some tool bits from LMS. I will test different bits and see how they work. I already have some ideas on how to shape them. It looks like I will have to make two bits, one for metal, and one for wood. Which is ok, it's still better then having to buy two separate machines or something else like that. And if it doesn't work, I'm just out $14, and still have a fly-cutter for metal.










Jason


----------



## Dwight Ennis (Jan 2, 2008)

Please keep us posted on things as they progress Jason. If working wood on a milling machine is do-able, I for one would like to know how to do it. That could come in real handy for some moulding I have to make for my cab.


----------



## Grimm (Oct 5, 2009)

Will do. I just went out today and picked up some hard wood from a local store here that specializes in it. Of course I didn't need much, so I searched through their cut-off bins. Came out with about 7 or 8 pieces of various types of hardwood. Total cost $7 including a nice short plank of oak for the base of the display.  The guys at the store were very nice and helpful. I'm building the base for the engine out of what looks like Brazilian rosewood, but I'm not sure. I also found some walnut for the fly-wheel. I should have the order from LMS in some time this week and then I can start on the fly-cutter.


----------



## Gary Armitstead (Jan 2, 2008)

Just a suggestion from an old die sinker regarding fly-cutters and fly-cutting......the distance you hang the cutter tip out from the center-line of the holder, is the same as the diameter of an end mill, when figuring the speed of the fly-cutter. In other words, if your toolbit tip is hanging out from the holder about say 1 inch, then it is 1 inch from the center and therefore the speed would be figured for a 2 inch diameter endmill. Always take into considration the material you are cutting whether it be wood, aluminum or steel. Also whether you are using high-speed OR carbide toolbits. 

Folks have a tendency to use speeds that are too fast for fly-cutting.


----------



## xo18thfa (Jan 2, 2008)

Gary just gave me an idea. If you grind a bit for your fly cutter to do metal, the same bit may work on wood to. Grip the bit close in and go slow speed for metal. Then increase the speed on the mill at max for wood.

Ordinary routers turn at incredible speeds, 10,000+++ RPM. Real industrial wood shapers don't turn anywhere near that that fast. You might be able to clamp the wood to the mill table and get a good cut.


----------



## SE18 (Feb 21, 2008)

Some folks who route use worn out bits to mill aluminum; the other camp decries the practice


----------



## xo18thfa (Jan 2, 2008)

Posted By SE18 on 28 Mar 2011 11:54 AM 
Some folks who route use worn out bits to mill aluminum; the other camp decries the practice 



I've heard them decry also. Don't understand why.


----------



## Grimm (Oct 5, 2009)

Thanks Gary.







Which does bring up a question I had. The blank arbor is 1.5 inches in diameter. I know that the tool bits are 2.5 inches long. Should I try and keep the tool and the bits as small as possible or should I keep it the size they are for the extra mass? I can always turn the arbor down and cut the tool bits.


Thanks Bob, I will definitely make the metal bit first and see how well it works on wood. According to the USPS tracking site, the parts should be here tomorrow.







I almost forgot, I'm going to have to stop by the hardware store and pick up some set screws. What size is normal? I don't have any metric taps so would a 6 or 8 work?


Jason


----------



## Grimm (Oct 5, 2009)

Ah, I found the fly-cutter plans, looks like they use 10-32s for the set screws, I have a tap for that so no problem. My (hopefully) last question is how to mount the arbor on my mill table? Dang, I may not be able to mount it on my mill. I have 1-2-3 blocks, etc. but it is going to have to be mounted vertically on the table and the arbor is very tall. I might have to get the guys at the university shop to help me on this.  

Jason


----------



## Semper Vaporo (Jan 2, 2008)

Posted By Grimm on 29 Mar 2011 03:38 AM 
Thanks Gary.







Which does bring up a question I had. The blank arbor is 1.5 inches in diameter. I know that the tool bits are 2.5 inches long. Should I try and keep the tool and the bits as small as possible or should I keep it the size they are for the extra mass? I can always turn the arbor down and cut the tool bits.


Thanks Bob, I will definitely make the metal bit first and see how well it works on wood. According to the USPS tracking site, the parts should be here tomorrow.







I almost forgot, I'm going to have to stop by the hardware store and pick up some set screws. What size is normal? I don't have any metric taps so would a 6 or 8 work?


Jason 



In general you want to keep the lengths of everything as short as possible... less flexing so more precise cutting to the desired size and more torque at the cutting-edge-to-work-piece interface.

But, if the fly cutter is short, then the surface speed of the cutting edge through the material is slower, so the bit needs to turn faster to maintain the correct Surface Inches Per Second. But then, cutting metal is usually done at slower speeds anyway.

High speeds also will throw cutting fluids all over more than slow speeds, too.

Trade-offs.


----------



## Grimm (Oct 5, 2009)

Thanks Semper, So in essence you are saying that I should leave the bits long to increase the speed at the tool bit tip? This would be good for wood I imagine. I don't plan on doing any kind of "hogging" with these tools. I guess if I rate the different materials that I plan on molding it would be wood first (the most), then brass, and finally steel. If I leave the blank arbor at it's full diameter then I would have more flexibility to adjust the bit length? It may all be moot any way as I don't think that I will be cutting any deeper then 1/8", although you never know.


----------



## Grimm (Oct 5, 2009)

*sigh* Well good news and bad news.







I found a way to mount the arbor on to the mill table, that's the good news. I used my 4-jaw lathe chuck and removed the attachment bolts, clamped the arbor into it and then lined it up on the table. Here is a couple of pictures of the setup:




















Everything was looking good and then I tried to cut the slot. The first bit I tried appeared to have trouble cutting the metal and I stopped once it started to look like the bit was starting to bend. Ok, I thought, the bit must be dull, I will try my other one. I also decreased the depth that I was cutting. The second bit just walked over the metal and didn't even cut.







So those were the only 1/4" end mills that I have and both are out of commission. I think that, at least, this arbor is not very soft on the end like they said it was.


















I guess that I'm going to have to anneal the metal and try again. Any other ideas? Very disappointing. 


Jason


----------



## Grimm (Oct 5, 2009)

Well I got some new end mills and just to be on the safe side I annealed the arbor to hopefully soften it up some. To anneal the arbor (or really to normalize it) I put the arbor end in my anvil's hardy hole to help keep it cool and hard. I then used both of my propane torches to heat the other end until it was just red hot and tried to cool it as slowly as I could. I then put it back on to the mill table and was able to cut it, finally.


















I don't know if it was the new cutter or if I was able to soften it a bit. The arbor was still hard to cut and I ended up chipping two of the teeth on the end mill. But I went really slow and only took off a little bit off at a time. This next picture is during the drilling holes and tapping process:











I really, really like the tap guide, well worth the money it cost I think. These last pictures are of the finished tool, now I can concentrate on cutter shapes and start testing on some wood and metal.




































Jason


----------



## RimfireJim (Mar 25, 2009)

Yes, those spring-loaded tap guides are extremely handy. I'm surprised that Fisher Machine seems to be the only manufacturer and that they are not more readily available through machine tool vendors. MSC sells a spring live center that is somewhat similar.


----------



## TrotFox (Feb 15, 2008)

A "better" method for fully annealing the part is to heat it in sand and then cover it before letting it warm up. That way the sand can hold the heat for a long time as the metal slowly cools. 

FYI for future projects. I don't know how well it would work for this one though because it sounds like you were trying to preserve the temper in the taper... 

Trot, the well-read, fox... :]


----------



## Grimm (Oct 5, 2009)

Thanks Trot, 

Yep, I was just trying to get it a little softer then it was. I guess they call it "normalizing" the metal instead of a full anneal like you described. More like drawing the temper I think. 

Jason


----------

