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Fly Cutter....

danielhv

danielhv

Well Known Member
I must be doing something wrong... cause I got this one from Sears:

http://www.sears.com/shc/s/p_10153_12605_00925293000P

and it isn't working for ****! Very sloppy holes, keeps moving the cutter to a different angle no matter how tight I tighten the set screw, etc. I butchered one of my tie down spacers cause the blade moved on me and started cutting the hole too big! :( Also, there is no easy way to make an exact measurement of where you have it set, there are no directions that come with it (although it should be self explanatory, but I must be doing something wrong because I have seen other builders that have used the same exact one!). Is there a better one somewhere or a better way of cutting holes?? I bought a 1" hole saw, but I'm sure I'll need to cut different size holes at some point in the build, I only hope there is a better way to do it!
 
I found speed to be one of the main issues when using a fly clutter. I think the one I have came from Avery Tools, its probably 13 years old now. The other thing I've done is to always put the piece I'm cutting on a larger flat piece of wood. Clamping everything down also helps but can be time consuming.

YMMV
 
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Daniel-

I have the same fly cutter and it works wonderful for me. First dumb question is are you using it in a drill press? Are you clamping the material you want to make the hole in down? Finally, make the drill press spin at the slowest speed possible - 300 RPM or so.

The final hole the fly cutter makes isn't the cleanest thing in the world. The fastest way to clean up and debur the hole is to use a dremel with some sanding drums.

Finally, as a safety tip with the fly cutter - don't use shop gloves with it. If your glove gets caught in the fly cutter it will take you hand with it since it is moving at a slow speed / high torque.
 
bullojm1 said:
Daniel-

I have the same fly cutter and it works wonderful for me. First dumb question is are you using it in a drill press? Are you clamping the material you want to make the hole in down? Finally, make the drill press spin at the slowest speed possible - 300 RPM or so.

The final hole the fly cutter makes isn't the cleanest thing in the world. The fastest way to clean up and debur the hole is to use a dremel with some sanding drums.

Finally, as a safety tip with the fly cutter - don't use shop gloves with it. If your glove gets caught in the fly cutter it will take you hand with it since it is moving at a slow speed / high torque.
Click to expand...



Yes, its on a drill press, at the lowes RPM the press will run (650rpm). Im clamping it to a piece of 2x4 thats about a foot long.
 
Below is a pic of mine. not sure where or when I picked it up. But once locked down it doesn't move.

RV7018-1.jpg


Like everyone said:
1. drill press only
2. slowest speed possible
3. clamped tight
4. easy on the pressure

also make sure your bit is in correctly. The one in your Sears photo won't work properly for ID holes. My holes needed very little work after drilling and the diameter was spot-on.
 
I had big time problems as well until I realized I had the blade oriented the wrong way, then it worked like a charm... :p
 
if you've got it going as slow as possible at 650rpm, your best bet is to make nice with the local machine shop. Have him cut the few big holes you need.

I'm not certain what you are trying to cut (got the QB -7 myself). but for thinner stuff you can use a punch, like these knockout punches.
 
As others have said, it's all about speed. 250-300 RPM max! I had a bench drill press like that, but had to get a floor model to get the speed and stability needed for using a fly cutter. Maybe check the local paper or Craigslist for an inexpensive used one. Also, Greenlee chassis punches work well, but are expensive. Harbor Freight has much cheaper ones which are probably fine for the limited amount of use on aluminum that this project needs.
 
I have had success...

...with a Sears drill press at 600 rpm and a General Brand (from Ace hardware) fly cutter.

Clamp everything down and press very lightly - cut the least you can off in every revolution.

For increased accuracy, I have removed the drill bit and replaced it with a 1/4 inch steel rod section. If you have a clean pre-drilled hole in the plywood backing piece, this will stop any side cutting, and movement, that the original drill bit might do as it penetrates the plywood.

If my reading of the tables is correct, a 650 rpm cutter for a 3 1/8 hole in aluminum is only 30% overspeed... That's for a 350 ft/min cut... some charts show a 600 ft per/min....

A liquid lubrication helps - the non-oil cutting fluids seem to be OK and less messy.

I got good instrument panel holes this way, and even large wing rib lightening holes (before Van cut them out for you...:)...)
 
I've been using the Harbor Freight one. It scares the heck out of me everytime I use it due to the wobble. I also have to resharpen the cutters every hole.

I always clamp the piece on top of some MDF and use lots of boelube. If I had more holes to cut I'd probably get a good one like the one Avery sells.
 
I used a GENERAL brand mounted in a 90 degree head connected to my cordless drill set on low speed..... used about 60 rpm to cut a 1.5" hole in the rear baffel mounted on the motor............... SLOW..... IS VERY GOOD!!! This was just above a stall speed for the cutter, and had very good control.
 
I use the fly cutter in a hand drill to cut holes in canopies for snap vents. :eek:

As far as the measurement, here is what I do. Take a dial caliper and measure the distance from the outside of the cutter to and including the center drill. Subtract 1/2 of the center drill diameter. Do the reverse to set it to a dimention you want. Works every time. Cut a test hole for accuracy.;)

On metal are you using a lubricating oil on the cutter?
 
i used the avery one. @30.00$ and one from lowes @10.00 $ both work great, look identical, except one is smaller.. no lube , clamped when possible, cover the surface with tape sometimes, 620 rpm's

clamping down the part really helps. however i dont always do that and that is risky to say the least. clamp when you can..i also cut the hole undersize about 1/16 to allow for deburring.

i found the harbor freight one to be useless and it cost more than the one from lowes.

now a hole saw i cant get to work on alu for ****.
 
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I have the same one ...worked fine..

I think I have the same fly-cutter from Sears. I have the cheapie Ryobi drill press, which only goes down to around 600RPM as well.

I had no problem cutting the tie-down spacer holes with it. I set the drill press to the lowest speed, clamped down the spacers on top of a small piece of 2x4, and used lots of the cutting lubricant they sell at Harbor Freight. As I was doing the first one, the cutter did get stuck in the aluminium, and the drill press got real angry real quick.:eek: After that, I learned to put very little pressure at a time. It was messy with all the cutting fluid, but the result was a very nice hole.

BTW, I started out with the harbor freight fly-cutter, but just watching it spin scared me enough to go buy the sears one....

Good luck...
 
fuel tank repair

We just cut 5 5" diameter holes in the baffle plate in an RV6 fuel tank last Sunday using 650 rpm on a benchtop drill press and the Sears fly cutter. The biggest problem was getting the workpiece square to the cutter.
Steve
 
cytoxin said:
Larry , you are a brave man...i salute you.;)
Click to expand...

Trust me, I have a beer afterwards. ;)

The trick is go 1/2 way though one side and then finish it on the other side. Maybe that would work good for metal and a drill press also?
 
I would also look at the bit, if it is backward as someone has mentioned it will get ugly. I think your drill press is fine.

JMHO
 
danielhv said:
So which way does the bit go? Its kinda diamond shaped... not sure which way goes towards rotation...
Click to expand...

Put it the way it came from the factory (per your pic link). The slanted side slants towards the outside. Basically, it is shaped like a square lathe tool. When I do it by hand you have to feed it so slow it hurts. Just play with it on some scrape. You're a good builder, you just have to get your head into it and figure it out. May the force be with you.
 
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Geico266 said:
Put it the way it came from the factory (per your pic link). The slanted side slants towards the outside. Basically, it is shaped like a square lathe tool. When I do it by hand you have to feed it so slow it hurts. Just play with it on some scrape. You're a good builder, you just have to get your head into it and figure it out. May the force be with you.
Click to expand...
I believe this is the way it goes, at least it worked for me this way.Others may disagree. Use a sharp razor or knife blade frequently to scrape the aluminum that builds up on the leading edge.
 
THE PICTURE IS WRONG!!

Geico266 said:
Put it the way it came from the factory (per your pic link). The slanted side slants towards the outside. Basically, it is shaped like a square lathe tool. When I do it by hand you have to feed it so slow it hurts. Just play with it on some scrape. You're a good builder, you just have to get your head into it and figure it out. May the force be with you.
Click to expand...

I MEAN THE SEARS PICTURE IS WRONG

The cutter is not installed correct. The point goes to the outside and the taper trails in the direction of the cut. If you cut slow like under 200 rpm and let the tool cut easy, you don't need any lube.......

p.s... Captainron has the correct picture.... In that case, the rotation of this cutter would be clockwise.
Look here............. http://www.vansairforce.com/community/showpost.php?p=257140&postcount=26
 
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gasman said:
I MEAN THE SEARS PICTURE IS WRONG

The cutter is not installed correct. The point goes to the outside and the taper trails in the direction of the cut. If you cut slow like under 200 rpm and let the tool cut easy, you don't need any lube.......

p.s... Captainron has the correct picture.... In that case, the rotation of this cutter would be clockwise.
Click to expand...
If you think about it, the cut should be complete just as the cutting tip goes through the aluminum sheet, and the cutter just scratches the backing board. If the bit was the way it is in the Sears picture, then you would have to continue the cut feed well into the backer board to finish the hole.
 
danielhv said:
Im clamping it to a piece of 2x4 thats about a foot long.
Click to expand...

Take another look at this photo from post 5. Thanks Brian.
RV7018-1.jpg


The entire stackup is clamped to the drill press table.

If you are only clamping to a piece of 2x4 as stated above, then things can still move around, and that aint good:eek:
 
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Mike S said:
Take another look at this photo from post 5.

http://i92.photobucket.com/albums/l40/Hydroguy2/RV7build/RV7018-1.jpg

The entire stackup is clamped to the drill press table.

If you are only clamping to a piece of 2x4 as stated above, then things can still move around, and that aint good:eek:
Click to expand...

I see, I'll give that a try too, its just hard enough trying to clamp that little piece down as it is and still leave room for the cutter! (2" x 1.25" tiedown spacer and cutting a 1" hole)
 
danielhv said:
I see, I'll give that a try too, its just hard enough trying to clamp that little piece down as it is and still leave room for the cutter! (2" x 1.25" tiedown spacer and cutting a 1" hole)
Click to expand...

1. your saving .2 grams

2. i would cut the hole before i cut the stock down.. makes it easier to handle. or use a drill press vise.
 
You can mount the 2x4 to the table from underneath with a few wood screws, then clamp to it.

Just keep all the parts firmly positioned.

The fly cutter exerts an asymmetrical force as it is spinning, and that is where the problem lies.

A drill bit has two cutting edges, which balance the force of each other.
 
bit orientation

If you want straight sided holes, the point of the tool must be to the outside. If you want cylinders with straight sides, set the tool with the point toward center.
I would use something other than a flycutter to cut lightning holes in the VS spar. Sears type fly cutters are best used for thin sheet stock.

Steve
 
Mike S said:
Take another look at this photo from post 5. Thanks Brian.
RV7018-1.jpg


The entire stackup is clamped to the drill press table.

If you are only clamping to a piece of 2x4 as stated above, then things can still move around, and that aint good:eek:
Click to expand...
If you can clamp the work to the table with the work up against the drill press' vertical column, that will help your physical well-being when the cutter stalls in the work!
 
Steve said:
If you want straight sided holes, the point of the tool must be to the outside. If you want cylinders with straight sides, set the tool with the point toward center.
I would use something other than a flycutter to cut lightning holes in the VS spar. Sears type fly cutters are best used for thin sheet stock.

Steve
Click to expand...
I spotted this little gadget at Chip Ganassi's racing shop. I think it punches holes from 1/8 inch to around two and a quarter inches, but it might be a bit more expensive than a fly cutter!

 
Cut my hole pannel out with one.

I had excellent luck with the same from ACS.

Slow speed, a little oil, wood board underneath, bit oriented properly and make sure it is sharp.

If you sharpen, don't burn the bit. I did sharpen periodically.

You might be putting too much force and not letting the bit cut at its own pace.
 
danielhv said:
I see, I'll give that a try too, its just hard enough trying to clamp that little piece down as it is and still leave room for the cutter! (2" x 1.25" tiedown spacer and cutting a 1" hole)
Click to expand...

I don't know if it makes any difference but I used a unibit and just drilled a 3/4" hole there.

.
 
Bi-metal Hole Saws

Since no one else mentioned this, I will. I have had much success using bi-metal hole saws designed to cut metal (not wood). The work piece has to be rigidly clamped and feed pressure light. Get Boelube in stick form and apply a little to the teeth on the hole saw just before you start cutting.

This method is more expensive than a fly-cutter but much less expensive than knockout punches. Over the years I have purchased various sizes from 3/4" - 6" diameter. You need to have a quality mandrel with dowel pins for the big diameters because they take a fair amount of torque. Also a slow turning drill press is a necessity for the largest diameters. In my former life I had an OLD (converted from leather belt drive) radial arm drill. It moved about as slow as me and had plenty of torque!

The suggestion about using a pin instead of a drill bit for the pilot hole is an excellent one.

Larry
 
Fly Cutting Holes

Hi All
The best way to use a fly cutter is to drill a 1/4" hole in the center of all of the locations for the fly cut holes.Then mount a 1/4" thick aluminum plate the same size as the drill press table to your drill press. Bolt it from the underside and grind the bolt flush with the top surface.Tighten the clamps of the drill press and drill a 1/4" thru the plate. This hole will act as bushing for the 1/4" drill rod you replace as the the guide in your fly cutter. Change the 1/4" drill bit in the fly cutter with a 1/4" drill rod. Locate your work piece with the drill rod thru the 1/4" holes and the plate,clamp in 3 locations as close as possible to the fly cut hole. remember to drill just enough to cut thru the work piece.
 
I found the surest way to use a fly cutter is to reinforce the panel to a piece of wood. Clamp it to the drill press. Drill out a pilot hole for the fly cutter and put 2 screws thru the aluminum about 1/2 inch from and on opposite sides of the pilot hole to stabilize the scrap as the fly cutter finishes the cut. The fly cutter passes easily over the head of the screws during the cut and in this way both the panel and the scrap are stabilized during the entire process.
 
One more thing.

Raise the table as high as you can and still be able to get the work piece in and out.

You are after the minimum extension of the spindle that you can get.

What you are achieving with the above is less lateral wobble in the rotating assembly, something that is always a concern with a fly cutter.

Daytons use of a 1/4" plate and a guide rod are very sound also.
 
Well, I gave up. I changed the cutter direction so that the point is on the outside of the cut which is what is pictured above by captinron, but by doing so, it makes the circle bigger. I've got the pilot bit slid all the way against the cutter (as close as it will adjust to rather) and its cutting a 1.5" circle. I just used a unibit and cut the 3/4" hole and moved on... I dunno about this fly cutter though, I may just take it back.
 
danielhv said:
Well, I gave up. I changed the cutter direction so that the point is on the outside of the cut which is what is pictured above by captinron, but by doing so, it makes the circle bigger. I've got the pilot bit slid all the way against the cutter (as close as it will adjust to rather) and its cutting a 1.5" circle. I just used a unibit and cut the 3/4" hole and moved on... I dunno about this fly cutter though, I may just take it back.
Click to expand...
Don't know quite what to say-
The diameter of the hole will be pretty much twice the radius; the radius is determined by the measurement from the centerline of the drill bit to the outside edge of the cutter. I don't think too many builders would use a fly cutter for holes only 3/4" diameter. Unibits and punches work much better here.
 
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