I have a bridgeport j-head varispeed. I want to get a decent length flycutter for it, first project will be facing the top and bottom of my 4-71. I'm not trying nor will ever cut heads or anything like that. anyone recommend anything or general use? I'm hoping to get something that will do 8" or so in one p***. I trust you guys more than some generic machining forum. Thanks guys.
Trying to swing an 8" circle will need you to have the head really dead nuts square to the table. Or you will cut a radius into the work. A smaller dia swing will greatly improve that situation. any flycutter that will hold a lathe bit will work for you, the supply houses sell them pretty cheap. MSC and Enco. Use diesel fuel, kerosene or WD-40 for a lube and a radius on the cutting edge will give a nicer finish than a sharp corner. Run it fast enough to send the chips to the other side of the room Frank
Do you have a boring head for your mill???If so , you already have your large DIA. flycutter....I routinly put a 4", or 6" long boring bar in my Criterion boring head, and flycut with it( in the hole that is perpendicular to the spindle , not parrallel). Have decked heads& blocks, along with fixtures for motorcycle swingarms (10-12" wide surfaces). As stated above, tram is everything, I try for under .0005...sometimes it takes a little while...be patient....Shawn...found pic... http://images.search.yahoo.com/imag...b=13j1d0j2q&sigi=12faqb2db&.crumb=VkNr6tp0NEX
Like it is stated in the above posts, Tram is very important. the longer the swing of the tram the more accurate the square will be. single point tool (fly cutter) will give you a nice finish if done correct. Ago
8" on a J-head is going to be very iffy. People have done it, with mixed success, but more than a few have also damaged the machine or the part in the process. As noted above, a relatively easy way is a boring head, with a boring bar that takes HSS inserts. (Not carbide.) Not the best way, but easy if you have the parts. An alternative is to buy a cheap Weldon-style endmill holder off eBay or whereever, and bore a perpendicular hole to accept a nice beefy bar, like 3/4" or even 1" round. Use the original endmill retaining setscrew to lock the bar in place. Bore the end of the bar to take a chunk of HSS, or even a round chunk of broken-off endmill shank. Make the bar the length of the diameter you want to cut- as in, you want to cut 8", make the bar 8" long. Mill a flat in the center to give the setscrew a pad to lock into. That way it's roughly balanced- there's an arm of roughly equal weight countering the cutting end. You'll still want to turn it very slow- no more than 80 rpm. Much more than that and you will bend a spindle or fling parts. Take very light cuts- maybe .005" or so, and power feed very, very slow. Grind a low-rake tool and hone it razor sharp, use lots of light oil as a lube. You will NOT be able to do it in one p***, unless the warpage is less than .005" or so. Trying to take too much cut, or even using to high a rake tool, will cause problems- chatter at best, bending the spindle at worst. Doc.
All my flycutters are ones I made but nothing strong enough to cover 8 inches. I would make one with a 6 inch body and .5" tool size for that and definately tram well! I tram my J-head on an old 8 inch bearing race within .0005". +1 on the WD40, nothing better to keep aluminum from gumming up the tools. You'll have some pretty high surface feet at that diameter! I pity the fool that walks by when your taking that cut... ouch!
I have made my own flycutters to take up to 5/8" carbide tipped lathe blanks. As stated in post #6, not something for the faint of heart to be doing unless you know your way around a machine shop. Post a picture of what you're trying to do, that'll be a big help and maybe some of us can come up with a better and safer method. Bob
I have faced 6-71 blowers on a BP, but always used a much smaller flycutter (3") and just profiled around by hand.
The head has got to be pretty much right on, best as you can get. I use 2 big parallels and a Starret Last Word indicator to tram mine. Agree with going with a big body.. and the biggest shank a R8 taper will take is a 3/4" maybe a bit bigger with a boring bar holder. RPM = (cutting speed x 4)/ tool diameter. Using a conservative CS for aluminum of 300, your RPM will be 150. Bob
is there a better way to face the blower? would yall suggest using a 3" flycutter and making two p***es? I havent trammed out my mill YET, but I will before I use it. I literally just finished rebuilding it(the mill). I'm just new at this thing whole thing with limited tools but I gotta start somewhere. I know enough to be dangerous.
^^so thats one yes for a 3". haha Im researching that Starret Last Word indicator right now as I need to tram my shiz "perfect".
at school we were taught to use this little c-clamp that attaches the dial to an endmill to set vices and what not. I could use this to tram the table out, but is there something that fits in the morse? would this be more exact?
I have a home-grown aluminum bar that takes the 3/16" shank of the dial indicator. Its pressed onto a 1/2" piece of steel rod and that goes in the collet. For quick and dirty, you can use a piece of 1/4" steel rod bent to a 90* angle, the short end goes in a collet and the indicator goes on the long end. Bob
...the MORSE ?? isnt it an R8 ? how you clamp up an indicator makes no difference; what does make a difference is the spindle bearings. on another note...something that looks odd and you'd swear wouldn't work is to mount an indicator on a tool-box and then indicate a part in on the table just by moving the table along its axis. (as long as you dont disturb the tool-box or indicator)
Really need to see what you're doing. If all the flycutting is on the external surfaces, you can make multiple p***es. Keep the p***es going in the same direction, or you can get a mis-match using a big diameter cutter. There is no such animal as a perfectly trammed out B'port head. Bob
it is r8. I am an idiot. Im cutting external surfaces. its the top and bottom of a 4-71 blower. aluminum. All my research keeps telling me my bridgeport isnt as rigid or straight as I thought it was.
I use a 4 inch Dia shell mill on a r8 holder. Use a mister as coolant spray., for a good clean cut. Using the correct table speed you can get a perfect grain to grip a seal/ gasket. If you use a wide of swing on a single cut fly cutter you. have a tendency to loose your cutting edge before you finish your cut, do to tool impact / vibration and distortion.\ Just square up you head to less then .001 of a inch on a 8 inch indicator swing, you will be fine. Get your self a shell mill cutter and arbor, you will not be sorry. Just remember the larger dia of cutter the slower spindle speed. Use a quality cutting fluid, one for ferrous and one for nonferrous metals. A mister (coolant via air pressure ) will keep the cutting surface clean of chip build up. producing a clean cut surface.
All you need to indicate (tram) is a circle = to the width of the table, 9" or so. Get that circle within .001" and you're good to go. Go with the smaller cutter or shell mill if you have one. Missed the above post when I was doing mine, that's what you need for best reaults. Bob
Here is a cheap holder for you dial indicator, clamps to the quill. $20/$25 At these prices, they are disposal. No big thing if broken. http://www.ebay.com/itm/Indicator-H...495?pt=LH_DefaultDomain_0&hash=item1e5b5b1057 http://www.ebay.com/itm/Turlen-Prec..._Automotive_Tools&vxp=mtr&hash=item5649db976f. .
Gasp... a store bought indicator holder. I've used them but have never owned one, maybe I should splurge. Bob
sweet. how much should I be spending on something like a 3" shell with a r8 arbor? ebay has them cheap and I ***ume ****ty quality. Mcmaster seems high?!?
If a shop had it, I used it. For myself, I have my homegrown reasonable facsimilies. And I even have flush toilets. Bob
Try www.mscdirect.com They have cheap **** up to pretty good quality. Even using a 2" or 3" cutter will be challenging in some materials like iron blocks. Make sure that you get a cutter that takes standard pattern inserts ie. TPG etc. Good luck, J
Ebay shell mills are fine, used. Most are sharpened buy quality cutter grinders, you will be fine. I by mine at quite a saving's. New quality cutters of this size are $ 225 to $400. plus the r8 arbor By a quality arbor for the shell mill as that is what gives the cutter stability. If you want I'll give you several tool houses, order via phone order. What part of the conutry are you ?
start with indicating the head in to the same dia as the cutter or bigger, second use a good quality high speed tool bit , take your time and take small cuts and you should come out ok enjoy
Here are a few good suppliers. They all will send you a free catalog, just sign up for their on line sales. http://www.msdiscount.com http://www.travers.com/ http://www.jlindustrial.com/
Remember, you have add twice the flycutter diameter to your part length to determine if you have enuff table travel. Because you need to run the backside of the cutter all they way off the end of the part so it doesen't leave a track.
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