### Help Support The Rocketry Forum:

#### Reed Goodwin

##### Well-Known Member
I've heard of this tool and seen the results that it can give, but I'm having trouble finding it locally. It's a tool that you can chuck into a drill press and then it has an adjustable arm that produces different diameter circles and then cuts them out, allowing for custom centering rings. Where have people been able to find this thing? So far I have looked at a Lowes, Home Depot, and a Northern Tool and came up empty-handed. Any ideas? I've heard Tractor Supply might have them, but the closest one is a solid 30 minutes away.
Thanks,
Reed

#### Brent

##### Well-Known Member
They are called fly cutters. I have not seen them at TSC. Harbor Freight has them but I would recommend a good one from someone like Wood Workers Supply.

#### troj

##### Wielder Of the Skillet Of Harsh Discipline, Potent
Get a good one, and always, Always, ALWAYS securely clamp the piece you are cutting. Never try to hold the piece by hand, or get your hands anywhere near it -- they inflict nasty injuries.

-Kevin

#### Chrisn

##### Well-Known Member
Make sure all the screws are torqued up well. I personally dont like them though, tools breaking on a CNC machine running at very high revs dont scare me as much as standing in front of one of these disk cutters on a drill press.

#### n5wd

##### Well-Known Member
...I'm having trouble finding it locally.
I bought one from these folks (Ebay auction link) for $15 postage paid - arrived in less than a week, and I've definitely been putting it to good use. It's nothing fancy, but seems to work well, and keeps the dimensions set rather well. My guess is that I'll probably buy a couple of additional units later - that way I can keep one or two set to the rings/bulkheads I wind up needing the most. #### rocdoc ##### Well-Known Member I've never used one of those, but I have used both the Jasper 200 and 400 Circle Cutting Jigs (http://www.amazon.com/dp/B00009K77A/?tag=skimlinks_replacement-20). They use a 1/4" bit in a plunge router to cut out holes and disks at 1/16" intervals over a large size range. Nowhere near as many dangerous-looking parts. Never had any difficulty using them and never worried about impaling myself. Last edited by a moderator: #### Reed Goodwin ##### Well-Known Member I've never used one of those, but I have used both the Jasper 200 and 400 Circle Cutting Jigs (http://www.amazon.com/dp/B00009K77A/?tag=skimlinks_replacement-20). They use a 1/4" bit in a plunge router to cut out holes and disks at 1/16" intervals over a large size range. Nowhere near as many dangerous-looking parts. Never had any difficulty using them and never worried about impaling myself. Maybe I'll look into whether I have access to a router. Actually thinking about it, if I have access to a drill press, I'll probably have access to a router. Thanks for the suggestion! Reed Last edited by a moderator: #### Gillard ##### Well-Known Member I bought one from these folks (Ebay auction link) for$15 postage paid - arrived in less than a week, and I've definitely been putting it to good use. It's nothing fancy, but seems to work well, and keeps the dimensions set rather well.

My guess is that I'll probably buy a couple of additional units later - that way I can keep one or two set to the rings/bulkheads I wind up needing the most.
i've recently purchased a hole cutter, like the one in the link, an it worked well, even my students were able to produce some good centering rings with it.

#### Micromeister

##### Micro Craftman/ClusterNut
TRF Supporter
I've found it actually works better of you buy two and sit it up to cut both holes at the same time inner first then the outer.

As others have already posted. SECURELY CLAMP the work, Wear SAFETY Glasses and a full FACE Sheild isn't a bad idea either, Gloves but always KEEP you Hands AWAY for the cutter while the press is turning.

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#### Brent

##### Well-Known Member
That's a great idea. I have 2 fly cutters but never thought about combining them.

#### rocketsmith

##### Well-Known Member
I have used these with varying success. The one thing I have found works well is to "onion skin" the cuts. Leave a thin layer of material at the bottom of the cut and use a hobby knife to remove the pieces and trim the "flashing"

#### jcDerRedMax

##### Member
1st trick with those is to drill 1/2 way from each side. The ridge in the middle makes for a tighter fit to the tube.

2nd trick is to dip the ends of the cross bar in safety orange. When the drill is on, you'll see an orange circle.

#### sodmeister

##### Well-Known Member
I have two similar cutters ,one was a cheap "generic" circle cutter and the other ,while looking very much the same ,is of much better quality.I bought the more expensive one at lee Valley Tools and the old saying"you get what you pay for" is very true.These particular cutters have a counter weight on one end ,and work alright ,but they take a bit of set up.What I now do when making CRs is to cut the outside ring with the circle cutter and use a toothed Forstner bit (also from Lee Valley) to cut the engine tube hole (24 ,29,38mm) ,I find this does a better job for me.

AND yes ,keep your eyes on that flying blade and clamp that work down !!

I like the idea of coloring the bar orange for visibility......much like propellers on aircraft.

Paul

#### troj

##### Wielder Of the Skillet Of Harsh Discipline, Potent
The safety orange on the end is a great idea -- even white would work. Anything that stands out and helps you keep your fingers and clothing clear of that nasty bugger!

Something I've not yet seen mentioned -- cutting speed. These need to be run at the slowest speed your drill press has, and take your time with the cutting.

-Kevin

#### Brent

##### Well-Known Member
Speed also depends on the material you are cutting. With this type of cutter you do need to feed slowly though never force. Another thing to look at is the quality of the drill press you are using and how you clamp your work. I prefer to use a mill with this type of tool but I do not have one at home. Another thing to remember is to always respect tools or machines you are using and use personal protective gear.

#### sodmeister

##### Well-Known Member
The safety orange on the end is a great idea -- even white would work. Anything that stands out and helps you keep your fingers and clothing clear of that nasty bugger!

Something I've not yet seen mentioned -- cutting speed. These need to be run at the slowest speed your drill press has, and take your time with the cutting.

-Kevin
Good point.I run at 500 RPM on my floor model 3/4 horse drill press for this cutter and Forstner bits.With bigger machines ,it`s too easy to muscle your way into the project,instead of letting the tool/cutter/bit do the work.

Just like making love.....nice and easy (unless my football games are on)

P

#### Commonwealth.Net

##### Well-Known Member
Fly Cutter ?
Or call us and let us LASER cut parts for you !

#### Reed Goodwin

##### Well-Known Member
Fly Cutter ?
Or call us and let us LASER cut parts for you !
Another excellent option! Everything is better with lasers! Will keep it in mind.
Reed

#### Solomoriah

##### Well-Known Member
Something I've not yet seen mentioned -- cutting speed. These need to be run at the slowest speed your drill press has, and take your time with the cutting.
I set my drill press on the slowest speed when I got it, and have never since changed it. I just don't see the need for speed here.

I do want a circle cutter, though. I wish I could buy a set of Forstner bits sized to make BT-5 and BT-20 sized holes... that'd be COOL. With both a circle cutter and a set of those, I could make cluster centering rings from birch plywood really easily.

I do know some people with a laser cutter but I haven't asked them about using it yet. I'm sure it'd cost me some...

#### luke strawwalker

##### Well-Known Member
I got one at Harbor Freight last year... works pretty well. Not the highest quality in the world but not the highest price either...

You really want to cut slow with these things and definitely let the tool do the work-- no down pressure to speak of. Cutting from both sides DEFINITELY is recommended.

You don't much see these things in the local hardware/big box stores because most of the stuff they sell is going to end up being used in a cordless drill or VSR hand drill-- and while I HAVE done it that way with a fly cutter, it's DEFINITELY NOT RECOMMENDED and at least a skill level 5 type of operation...

Later and good luck! OL JR

#### ONAWHIM

##### Well-Known Member
Troj mentioned clamping.

When I cut small items on a drill press I will screw the material I am cutting onto something sacrificial underneath. Obviously the screws would be outside of the cutting area.
If you use something appropriately sized you can clamp it down.

Cut through your material and into was is under it.

Wm.

#### slogfilet

##### Well-Known Member
Over the weekend I tried the Dremel circle cutting attachment (ordered it from Amazon last week.)

I was pretty impressed with the results. I made several 54mm bulkhears and some 54-38mm centering rings, and everything came out 100% useable! I was using 1/8" birch ply; I'm going to try it on some 1/4" for a crayon project.

Haven't heard too many folks mention it, but I found it to be a good tool.

Here's a link... \$15 on Amazon:
http://www.amazon.com/Dremel-678-01-Circle-Cutter-Straight/dp/B000HI5WTY/ref=sr_1_1?ie=UTF8&s=hi&qid=1263242639&sr=8-1

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#### n5wd

##### Well-Known Member
Haven't heard too many folks mention it, but I found it to be a good tool.
I've tried it, but either I lack the proper technique or patience to get it right with the Dremel attachment - glad it's working for you!

#### Stymye

##### Well-Known Member
I use a good quality double back tape and stack cut several at one time.
I cut the outer diameter only as "blanks"

when I need a finished ring, I cut the appropiate inner diameter with a hole saw or appropiate size tool using the pilot hole that the flycutter left for centering.
or I use them as is, for bulkheads

usually all thats needed from that point is a little fine tune sanding.

I set up and cut about 80 different blanks in a couple hours.

this batch has lasted me a long time and I can now whip out a finished ring in minutes

#### slogfilet

##### Well-Known Member
I can see how the fly cutter would be much faster for making multiple pieces (especially at the same size.) The Dremel attachment does takes some time to set up for each cut.

But if you lack a drill rpess but have a rotary tool, it's a decent option. I figure whatever method/tool you use, it'll pay for itself in short order!

#### CF-105

##### Well-Known Member
Troj mentioned clamping.

When I cut small items on a drill press I will screw the material I am cutting onto something sacrificial underneath. Obviously the screws would be outside of the cutting area.
If you use something appropriately sized you can clamp it down.

Cut through your material and into was is under it.

Wm.
For cases where there's not enough clearance for clamps, I tack the material down with small finishing nails.

I now have a collection of these things, all set at specific diameters (and labeled). If I need to cut rings or bulkheads of those sizes again, there's no need for "test" cuts.

#### Micromeister

##### Micro Craftman/ClusterNut
TRF Supporter
For cases where there's not enough clearance for clamps, I tack the material down with small finishing nails.

I now have a collection of these things, all set at specific diameters (and labeled). If I need to cut rings or bulkheads of those sizes again, there's no need for "test" cuts.
Not enough room for clamps LOL!!??? Turn the C-Clamp over LOL!!!

#### CF-105

##### Well-Known Member
Being a packrat, I have a hoard of scrap ply. Often I'm cutting from material that's barely big enough to do the job. Clamps aren't an options in those cases.

#### RocketFeller

##### Well-Known Member
I love my adjustable circle cutter, I'll never buy another centering ring!

I picked up my circle-cutter at my neighbor's junk sale, it was second-hand but seemed brand-new and I got it for a buck. I suspect it is a fairly cheap one as it has to be readjusted after every two or three rings cut.

One trick I figured out for cutting rings without clamping/nailing/screwing is to use a great-big pair of channel-lock pliers to hold the rings.

My method:

I cut the outer circle first. I use a sacrificial piece of plywood under the CR stock and set the height of the platform so the cutter will cut a sixteenth or so into the plywood.

If I am cutting out of a big piece I just hold with the left hand and crank with the right. If it is a smaller scrap I clamp it somehow.

After I cut the discs I switch the cutter and cut out the inside cut holding the ring with the Channel-Locks. This works really well on 4" and under rings, for bigger rings the pliers won't work, of course.

#### THier

##### Well-Known Member
I've never used one of those, but I have used both the Jasper 200 and 400 Circle Cutting Jigs (http://www.amazon.com/dp/B00009K77A/?tag=skimlinks_replacement-20). They use a 1/4" bit in a plunge router to cut out holes and disks at 1/16" intervals over a large size range. Nowhere near as many dangerous-looking parts. Never had any difficulty using them and never worried about impaling myself.
Agree 100% with this,, can't go wrong with it and MUCH safer and more precise than a fly cutter.

Tom

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