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coollx
08-17-2009, 01:00 PM
I have a small boring head (2" or 2 1/2") that I want to try flycutting some aluminum with on my BP. I did some research on this board regarding doing this and it seems possible.

I recognize that the boring bar needs to be mounted horizontally but I'm not sure how to set the head and bar up since the cutting tip of the bar is higher then the bottom of the boring head. Do I need to tilt the head of my BP in order to get the tip of the bar lower than the boring head?

Would appreciate any pointers.

Thanks

Dom

Oldbrock
08-17-2009, 01:10 PM
I presume you are trying to use the boring bars that come in a set. No, you need to make a bar with a 1/4" square hole in the end to hold a toolbit and a set screw to hold it. Then you can set the toolbit out enough to clear the end of the head. If you can't cut a square hole then just mill a slot in the end of the bar to accept the toolbit. as you are only facing Al then this should be satisfactory. Peter

airsmith282
08-17-2009, 01:20 PM
why not just use the proper tool for the job,it would work better and much safer as well..

i have see diagrams on the net for making a fly cutter seems rater simple and all don on the lathe,, anyhow its your choice but my moto is proper tool for the job or i wont attempt it ,

Jack F
08-17-2009, 01:32 PM
I wouldn't subject my boring head to this kind of abuse. They weren't made for interrupted cuts and fly cutters are easy enough to make. "Google" "home made fly cutters" and you will find many plans.

Jack.

Alistair Hosie
08-17-2009, 05:04 PM
Besides these points flycutters are really inexpensive to buy see ebay for example.Have fun.Alistair

coollx
08-18-2009, 12:27 PM
Actually, I have a regular 2 1/2" fly cutter. I asked the question about using a boring head because I thought that it might be a way to make a wider cut with a single pass using tools I already have.

I'll do some additional research on the internet to see if I can find plans for building something with a bigger cut.

Thanks for the input.

beckley23
08-18-2009, 07:11 PM
Who says boring heads aren't made for interrupted cuts. Take a look at this topic. That boring head is still doing excellent work, holding tenths on bearing bores.
http://www.practicalmachinist.com/vb/showthread.php/geared-taper-attachment-variator-99359.html
Harry

JCHannum
08-18-2009, 07:30 PM
This was discussed here just a couple of weeks ago;

http://bbs.homeshopmachinist.net/showthread.php?t=36138

Jack F
08-18-2009, 10:19 PM
Hi beckley23,
That was me. I admit I am new to this game but boring heads were made for boring. I also admit that thread on PM seems to contradict my premiss. However the metal used in that thread looked like Alum. to me (I could be wrong) and the boring head looked pretty stout. Still I would not subject my head (A 4" maxwell, very stout) to that abuse. I would have used my R/T and an end mill. He already had the shaft bores for each half to index to.

Jack

beckley23
08-18-2009, 10:33 PM
The material is steel. That is a boring operation of 2 halves of a hole separated by approx 3". The cavity was roughed out with a rougher end mill and the sides finished with a finisher. Each half was done in several passes.
I thought about doing the cavity on a rotab, but set up and machining would have taken considerably longer.
Harry

Carld
08-19-2009, 06:36 PM
I visited Harry today and saw the part he machined with the boring head and it was a good match for a boring head. Using a rotab to do the job would have been more setup time and complicated the job as I saw it, plus the finish was excellent.

coolx said, "I recognize that the boring bar needs to be mounted horizontally but I'm not sure how to set the head and bar up since the cutting tip of the bar is higher then the bottom of the boring head."

Do you have the cutter in the OD of the head rather than the bottom of the head? That is what it sounds like from what you said above.

coollx
08-19-2009, 07:21 PM
Carld

Yes, I was thinking I could mount the boring bar in the horizontal holes that are on the OD and run from one side of the head through the other side. These would be the same holes one would use to mount a boring bar to bore a large hole. Another reason trying this has some appeal is the bar could be retained by two set screws in the horizontal position which would make it very secure.

Dave Converse
08-19-2009, 07:46 PM
I've done exactly that, but not with brazed carbide for the reason you described. I have a 4" boring head that holds 1" diameter bars. I installed a bar with a HSS cutter in the end to surface a large area. Someone made the observation that it probably doesn't do the head a lot of good, though. It did work well, but I think I'll stick to flycutters in the future and save the boring head for it's intended purpose.

Carld
08-19-2009, 11:37 PM
Coollx, why do you want to run a bar through the hole in the boring head to make a flycutter? Is it to get a large diameter cut? There is no reason it won't work but you will probably have to weld a brazed carbide tool to the end of the bar to cut with and it may be best to use a V nose cutter because it would have less chip load.

If I were going to do that I would take a piece of 2" square stock and turn down a 3/4" shank on one end and then drill a hole the size of the bar perpendicular to the 3/4" shank and a couple of set screws to lock the bar and that would make a better large diameter flycutter. I have one like that and it works pretty good if you don't take heavy cuts.

For one thing, I don't think you can get a big enough bar in your boring head to be rigid for a large diameter.

Black_Moons
08-20-2009, 03:50 AM
Seriously just buy a set of flycutters, you can get 3 peice sets for $20~30 (1/2" or 3/4" shank, up to like 2"+) and they will hold much larger then 2" 'diamiter' since the bit protrudes typicaly anyway.
(or the full 6 peice set for like $60)
I dare you to make a better set for cheaper while valueing your time at $20/hr.
(if you can, you are awsome)

http://busybeetools.ca/cgi-bin/picture10?NTITEM=B089 for an example :)

Hardened steel even, (so they claim).. at least its been tool dyed.

Davek0974
08-20-2009, 04:09 AM
I wouldn't subject my boring head to this kind of abuse. They weren't made for interrupted cuts and fly cutters are easy enough to make. "Google" "home made fly cutters" and you will find many plans.

Jack.

Does this count as interrupted;)
http://d.yimg.com/kq/groups/17605961/sn/522881902/name/DSCN0974.jpg

Seriously though, i would get a flycutter, they are real cheap.

Dave

oldtiffie
08-20-2009, 05:48 AM
Here's a boring bar in the horizontal hole in my boring head - works well:
http://i200.photobucket.com/albums/aa294/oldtiffie/HF-45%20Mill%20misc/Fly-cutter5.jpg

Vertical:
http://i200.photobucket.com/albums/aa294/oldtiffie/HF-45%20Mill%20misc/Fly-cutter6.jpg

And a 5/16" tool-holder welded to a 20mm adaptor to suit my largest ER-32 collet. It is surpringly well-balanced.
http://i200.photobucket.com/albums/aa294/oldtiffie/HF-45%20Mill%20misc/Fly-cutter4.jpg

They will all work well as fly-cutters - or boring bars - buy I prefer the tool-holder-cum-adaptor for larger fly-cutting or roughing work for boring. Its easy to adjust the tool as required.

The boring-head is saved for lighter-load and finish boring work.

spope14
08-20-2009, 04:22 PM
AH HA, found a use for those old armstrong cutters I have kept in a box for 20 years now....

Jack F
08-20-2009, 04:32 PM
OK you guys I stand corrected:) . If I come across a boring job with interrupted cuts I will try the boring head. I will however stick with a fly cutter for the surface cuts;) .

Jack.

spope14
08-20-2009, 04:49 PM
Though it would probably work, the specific questions to the poster are what type of machine, Z axis throw of the machine and such right to horsepower. also other things like depth of cut.... Some situations a boring head probably works, but in others I would seriously look at overall rigidity of the whole process. A fly cutter is right there up to the top of the spindle and can be run close top the head casting to prevent flex and machine head rigidity issues. A boring head adds the length of the head mechanism and then the cutter away from the casting, and may even start to tweak some slightly worn (but normally sufficient otherwise) bearings a bit, causing some surface irregularities.

I have tried a lot of great ideas in concept and others practice only to be tharted (and humbled) by the limits of the available machine.

I guess, it all comes down to "what is your base iron".

Jim Shaper
08-20-2009, 05:32 PM
A boring head is going to be far more rigid than any fly cutter I've ever seen.

I don't know why you guys seem to think that swinging a tiny little fly cutting tool bit is going to somehow ruin your boring head, the load is no heavier, so long as the loose nut behind the hand wheel (i.e.: operator) isn't trying to shave a ton off in a single pass.

Boring bars are INTENDED for interrupted cuts. The whole point of boring a hole is that you can move the thing from where the center of the original hole is (like when sleeving worn bores - duh!).

If side loading were such an issue, you'd be making tapered holes from the get go. The major detraction from using a boring head in lieu of a fly cutter is the amount of daylight you sacrifice under the spindle.

I personally don't own a fly cutter. I use a carbide face mill for anything needing facing. The DOC and speed at which you can run the tool is far superior to a fly cutter; not to mention I can get a 32 finish while running the feeds at 8ipm with a .100 DOC.

S_J_H
08-20-2009, 05:58 PM
Flycutting at a light DOC does nothing harmful to a boring head. I always locked the gib on the boring head. I used this quickie setup for a while for certain jobs. It ran a lot smoother than my import integral r8 body flycutter that's for sure. I could get a very good balance with the boring head rig and run it up to 4000rpm if need be.
Steve

http://i109.photobucket.com/albums/n48/S_J_H/x3%20mill/Granddadproject006.jpg
http://i109.photobucket.com/albums/n48/S_J_H/x3%20mill/test024.jpg

coollx
08-20-2009, 10:36 PM
Gee guys, after the first couple of responses to my original thread I figured my idea was a bad one. Maybe to some of you it still doesn't make sense, but I'm encouraged by many of the positive responses received where others have successfully used variations of what I was thinking about doing.

I may have said it before, but I do have a factory built 2 1/2" flycutter with a intregal R8 shank. I asked the original question because I'd like to find a low cost way to be able to make shallow (.002-.004) 7"-8" flycuts in aluminum in a single pass. Using a boring head, which I already have, just seemed like a quick possible way to accomplish what I was looking to do.

I'm sure its obvious that I'm new to all of this but am trying to learn as I go along.

BTW, I have a BP J Head w/ a 42" table and 1 HP 3P motor.

Thanks for the feedback.

Dom

Carld
08-21-2009, 11:06 AM
It will work as long as the cutter is below the head as in the photos above.

hephaestus
06-02-2016, 12:41 AM
LOL, I just asked this same question in the general forum but didn't have any immediate responses, so I did an internet search. Funny this site popped up.

Paul Alciatore
06-02-2016, 04:04 PM
Guys, I think a basic question has not been asked or answered. The OP talks about WIDER cuts. I suspect he is trying to make a wide (7" or more) FLAT surface. That could be why he was worried about the boring bar being above the bottom of the boring head. Some of the posts have addressed this, perhaps by accident or perhaps by intent. But most of you seem to be thinking he wants to make a partial cylinder.

I would suggest that a fly cutter could be made at almost any diameter as I have done here:

http://img.photobucket.com/albums/v55/EPAIII/FlyCutter4In.jpg (http://smg.photobucket.com/user/EPAIII/media/FlyCutter4In.jpg.html)

This one was made for milling in my SB lathe and it fits the spindle threads there. But I made an adopter so I could use it in my vertical mill. It is well balanced so the large size is not a problem. With two HSS bits, it cuts very smoothly. I liked it so much that I made a smaller version for my Unimat: it also mounts directly on the spindle threads.

By the way, I made it completely on the SB lathe and my drill press. Here is a shot of it being milled there.

http://img.photobucket.com/albums/v55/EPAIII/PixB.jpg (http://smg.photobucket.com/user/EPAIII/media/PixB.jpg.html)

This was before I had a milling machine.

Paul Alciatore
06-02-2016, 04:05 PM
Guys, I think a basic question has not been asked or answered. The OP talks about WIDER cuts. I suspect he is trying to make a wide (7" or more) FLAT surface. That could be why he was worried about the boring bar being above the bottom of the boring head. Some of the posts have addressed this, perhaps by accident or perhaps by intent. But most of you seem to be thinking he wants to make a partial cylinder.

I would suggest that a fly cutter could be made at almost any diameter as I have done here:

http://img.photobucket.com/albums/v55/EPAIII/FlyCutter4In.jpg (http://smg.photobucket.com/user/EPAIII/media/FlyCutter4In.jpg.html)

This one was made for milling in my SB lathe and it fits the spindle threads there. But I made an adopter so I could use it in my vertical mill. It is well balanced so the large size is not a problem. With two HSS bits, it cuts very smoothly. I liked it so much that I made a smaller version for my Unimat: it also mounts directly on the spindle threads.

By the way, I made it completely on the SB lathe and my drill press. Here is a shot of it being milled there.

http://img.photobucket.com/albums/v55/EPAIII/PixB.jpg (http://smg.photobucket.com/user/EPAIII/media/PixB.jpg.html)

This was before I had a milling machine.

Yondering
06-02-2016, 04:24 PM
Check the date on this thread Paul. I think the discussion has been over for a while...