what hole saw bits do you use for your mm and baffels?

[3boydad]

i bought a set from harbor freight. looks like it does 24mm perfect 29mm is a little sloppy. as for bt, say a bt-80 its either a little too big or too small. anyone have suggestion on what and who sells what im looking for? i bought some birth and i wanted to make a mm and cut some fins for my second sbb i am constructing.

[Micromeister]

i bought a set from harbor freight. looks like it does 24mm perfect 29mm is a little sloppy. as for bt, say a bt-80 its either a little too big or too small. anyone have suggestion on what and who sells what im looking for? i bought some birth and i wanted to make a mm and cut some fins for my second sbb i am constructing.

Body tube OD's and standard Hole saw OD's are usually pretty different. 13mm Body tubes for example .544" OD is pretty close to 1/2" hole saws but with the teeth set they generally come out far to big for use. BT-80 on the other hand at 2.6" OD is simple not "close" to anything you'll pick-up at Harbor Freight....That is short of an adjustable flycutter ONLY used in a Drill Press.

What material are you cutting? Unless your using heavy plywood or basswood over 1/8" Knife blade circle cutters are usually a better way to go since you can adjust them to the exact diameter you want. If using those heavy woods I generally layout the OD, ID or both with a pencil or ink compass than cut out the center hole with a smaller holesaw. To finish off the ID's I'll mount a Drum sander in the drill press and work to the line of ID sanding. OD's are sanded to the line on a vertical belt sander that has had the work table leveled. Takes a bit longer but the fit is always MUCH better. I also like to stack sand a number of extra centering rings of different materials all finished at the same time so the next time I need a certain centering ring in Ply, bass, cardstock or heavy board they are in my parts boxes. Stack cutting/sanding is very easy with a roll of 1" double faced masking tape and the tools mentioned earlier.

[cavecentral]

A drill press and this will cut any size you want in 1/8 or 1/4" ply. For 1/4" I go in half way, flip and got from the other side. Remember to swap the points for clean OD and ID holes. I bought several and plan to leave a set at 54, 38, and 29mm.

http://www.harborfreight.com/carbide...ter-68117.html

[cwbullet]

They work, but it can be scarry even on a drill press.

[cavecentral]

They work, but it can be scarry even on a drill press.

Keep your hands and feet inside the vehicle at all times!

[cwbullet]

Keep your hands and feet inside the vehicle at all times!

I wear goggles, kevlar gloves, and armored underwear just in case parts fly off the circle cutter.

[cavecentral]

I wear googles, kevlar gloves, and armored underwear just in case parts fly off the circle cutter.

But you apparently use it. I do googles. Smacked my knuckles a few times. Never had parts fly off.

For safety, I just have my kids do it. (Kidding - I don't have kids).

[cwbullet]

But you apparently use it. I do googles. Smacked my knuckles a few times. Never had parts fly off.

For safety, I just have my kids do it. (Kidding - I don't have kids).

Danger, Will Robinson. Danger!

I had the cutter come off a couple of times. I have only has it happen with the double cutter model. It wobbles and flew off.

I use a Rockwell blade runner with a circle cutting jig.

[Davidtmp]

I wear googles, kevlar gloves, and armored underwear just in case parts fly off the circle cutter.

I use google too, but not for anything on a drill press. I usually use google on the computer, and goggles on the press.

[cwbullet]

I use google too, but not for anything on a drill press. I usually use google on the computer, and goggles on the press.

Darn computer and bifocals.

[chadrog]

I wear goggles, kevlar gloves, and armored underwear just in case parts fly off the circle cutter.

Where do you get the underwear, I could use some.

[cavecentral]

Where do you get the underwear, I could use some.

Check an S&M store? Otherwise, maybe a sporting cup.

[dr wogz]

I've made a few chain mail tops.. mainly for the women though..

Aluminum rings & copper wire rings..

[chadrog]

Those are cool, nice work! Can you make them in "rocketeer medium"?

[BEAR]

If you will allow me to offer a suggestion. A method I use when using my drill press and circle cutter is to take a piece of 3/4" particle board with the white plastic laminate (1/32" formica)on each side and put a layer of heavy duty double sided carpet tape on it. Then I take my plywood that I am going to cut up to make my centering rings and press that firmly on top of the carpet taped area so it is very secure. This gives me something to hold on to, something I can clamp down, and soemthing that keeps my digits out of the way. Sometimes I lay everything out on the plywood with a compass so that I have pencil marks for guides and I will also mark my centers so that I know where to start my center drill. I do the outside of a circle first, and then cut out the center. I also leave room between circles for the width of the cutting tool. I use digital calipers for setting the diameters, and the first cut is reallly just a scratch so that I can check my diameter. As long as I am not too agressive in my cuts but keep it slow and steady, I never have any problems. I also try to avoid interupted cuts where the cutting tool breaks out of material and then goes back in because this causes a really hostile vibration. I also have made it a habit, from my learning process in the beginning, that if a part comes loose from the tape, never ever raise your quill on the drill press until you have the motor turned off and the spindle comes to a complete stop. This keeps thing from becoming airborne. I keep several circle cutters around already set for certain diameters. Also, keep your cutter sharp. If it is dull and dragging, then you are placing extra strain on the tape. I promise you this method will works every time if you are cautious and pay attention to detail. I can use the same peice of 3/4" base over and over, as long as I peel all of the old tape off, remove all adhesive, and wash the surface good with alcohol or thinner or some sort of solvent so that the tape has a good surface to stick to. I have done this on big sheets and cut a couple fo dozen rings in the same setup.

[T-Rex]

I have bought a couple hole saws but haven't had opportunity to use them yet. I bought hem deliberately over/undersize and plan to sand the parts to fit. Should work well for the OD of centering rings but the ID will take some work. I don't have a drill press so I will be working with a hand drill. I may get some 1/4" ply or a sheet of luan to practice on before I attempt something important. There too, comparing the cost, maybe I will just go to HF, get a cheap drill press & be done with it.

[3boydad]

well i dont have a drill press. although thats something i am looking to purchase in the future. however 24mm and 29mm are np as i have those sizes. i cu test holes and the tubes fite perfect. the 29mm needs just a little bit of sanding for a nice snug fit. its the bt i am having a problem with. i have a 2.5 inch and a 3 inch. the 2.5 inch is a little bigger than the bt-80 so it will take some sanding for sure. i did buy a set of drill sanding bits but what a pia.

[3boydad]

i also bought a jigsaw with the fine 20 teeth per blade for fine cutting for the fins. that should be easy then again i could always use the jig i guess to cut the mm

[cavecentral]

I like the tape idea. Might have to try that. The layers of skin lost due to holding the outer ring while cutting the inner and having it finally build enough friction to spin and burn a layer of my thumb and fore finger off are pretty high. Like a plywood papercut.

[Davidtmp]

I have stuck a screw threw the center hole, attached a nut and tightened(also used a couple of those toothed lock washers to hold it in place). Stick this in a drill, and then you can hold in one hand and sand to fit with the other, using a sanding block 'cause that paper will get hot. Could put drill in a vise if you have one. Could stick the screw in a drill press I would think as well.....depends on what you have on hand to use.
Look at Quake's build thread on I think the Vagabond build.....he has a lathe that he uses to get to the proper size.
Many ways to achieve the correct fit.

[thobin]

Man nothing like a good knuckle smack down from a errant centering ring.

TA

[cwbullet]

Man nothing like a good knuckle smack down from a errant centering ring.

I have done that while just drilling a hole.

[scsager]

i bought a set from harbor freight. looks like it does 24mm perfect 29mm is a little sloppy. as for bt, say a bt-80 its either a little too big or too small. anyone have suggestion on what and who sells what im looking for? i bought some birth and i wanted to make a mm and cut some fins for my second sbb i am constructing.

Qquake2k has a bunch of build threads in the Scratch forum - he is able to make the rings he needs. You might try checking out some of his excellent threads.

I just don't have the tools or the shop for cuting my own. For me - much easier to buy what I need from Balsa Machining Service (up to BT80) and LOC ( or Hobbylinc) for the 3" and 4" rings.

[Micromeister]

for LPR & MPR centering rings power tools really aren't necessary. If your worried about strength simply laminate a couple thinner rings togther to whatever thickness your most comfortable with. I hear folks talking about using 1/4" ply for rings in mpr birds and wonder Why! If you look at the engineering two 1/8" rings fore & aft on a 38mm motor mount are more then strong enough to hold up without all that excess mass. besides it's the epoxy fillet inside between airframe and ring that hold our models together. Over building just lowers the potential performance of the birds.

All that said it's a bit harder on the fingers to cut 3/32" Plywood with a Manual Beam type Circle cutter but is in fact very doable. If your not stack cutting and finishing 12-20 rings with a scroll saw, drum & vertical sanders then these circle cutters are Perfect for cutting one's and two's in Basswood, lit ply, heavy cardstock, and 14ply shocard. Do they ware on the fingers...absolutely but are a lot cheaper then the shop Tools, quicker & usually cheaper then waiting for rings to arrive in the mail

I'm lucky enough to have all the tools but still find myself using these circle cutters more often then one might think.

[qquake2k]

I use 1/8" and 1/4" plywood almost exclusively for centering rings. I'm blessed to have a drill press and lathe, and a large number of traditional hole saws. For the OD of the rings, I mount them on the lathe with a 1/4" bolt through the pilot holes. I've found a bastard file works best for me for trimming them to size. For the ID, I choose the closest hole saw I have to the motor tube, but that is smaller. I use a sanding drum in a Dremel to sand the ID to the final size. I have also used a scroll saw for centering rings, with a homemade circle cutting jig. If I didn't have all the power tools, though, and only needed a few centering rings, I'd probably just order them from Balsa Machining or LOC (Hobbylinc).

http://www.rocketryforum.com/showthr...883#post331883

http://www.rocketryforum.com/showthr...691#post244691

[GregGleason]

... I just don't have the tools or the shop for cuting my own. For me - much easier to buy what I need from Balsa Machining Service (up to BT80) and LOC ( or Hobbylinc) for the 3" and 4" rings.

+1

I am using BMS more and more. I have the tools, but not the time. It is so much easier to spec out what I want size/material wise, then order it. The box of goodies arrives about a week later. Plus I get laser cut precision from what they send me. Makes me wonder why I didn't do it sooner.

Greg

[cavecentral]

+1

I am using BMS more and more. I have the tools, but not the time. It is so much easier to spec out what I want size/material wise, then order it. The box of goodies arrives about a week later. Plus I get laser cut precision from what they send me. Makes me wonder why I didn't do it sooner.

Greg

Once I get my press setup, I do 10 rings / bulkheads / etc. Setup is the toughest. Then I have some ready to go for the next one.

[3boydad]

for LPR & MPR centering rings power tools really aren't necessary. If your worried about strength simply laminate a couple thinner rings togther to whatever thickness your most comfortable with. I hear folks talking about using 1/4" ply for rings in mpr birds and wonder Why! If you look at the engineering two 1/8" rings fore & aft on a 38mm motor mount are more then strong enough to hold up without all that excess mass. besides it's the epoxy fillet inside between airframe and ring that hold our models together. Over building just lowers the potential performance of the birds.

All that said it's a bit harder on the fingers to cut 3/32" Plywood with a Manual Beam type Circle cutter but is in fact very doable. If your not stack cutting and finishing 12-20 rings with a scroll saw, drum & vertical sanders then these circle cutters are Perfect for cutting one's and two's in Basswood, lit ply, heavy cardstock, and 14ply shocard. Do they ware on the fingers...absolutely but are a lot cheaper then the shop Tools, quicker & usually cheaper then waiting for rings to arrive in the mail

I'm lucky enough to have all the tools but still find myself using these circle cutters more often then one might think.

i have the circle cutter to the far right. it alright for balsa but thats pushing it. im getting a drill press. they really are not that expensive, 70 bucks and i own one from harbor freight. i wanna do the big birds and make my own rins for the msaller birds too. i find i have the right bite 25mm cuts perfect for 24mm and i have a 29mm and just needs a little sanding its the outter i cant get right. drill press soon if the wife will allow it.