well I got started on my boring bar, just have to get my drive unit built now. I have to edit my pics so I can post them.
Looks good. I am at about the same stage in my boring bar project. Bar built but still debating how to turn and feed it.
Im eventually building a hydraulic drive system like i drive my tapping machine at work. Right now though, I have a smaller table top drill press that Im going to try and add a rheostat for variable speed and mount it sideways to drive the bar. Will post more as it proceeds.
Sounds interesting please keep us up to date
I've never done any line boring before but would quite like to give it a go for interest sake. I have considered using a mixing drill to power the bar similar to the type used by plasterers. The one I looked at was variable speed between 0 - 800rpm and around 600 watts. Do you think this would be sufficient if I took it steady? So no more than about 100rpm and not take too big a cut?
I don't want to hi-jack your thread, but, here are a few pictures of my "home built" set up. Basically I copied the York setup. I used a 1/2" drill motor to turn the bar. A millng machine power feed to feed the bar, geared down 3:1. The drill motor worked good, but a little under powered. It has the right speed but could only handle .010" cut depth. After working the bugs out, I swithced over to a 3/4" mag base drill motor. It has variable speed, forward/reverse and a lot more ass! Third pic is a cutter attachment I made for bigger holes. I drilled/reamed my bar, and use boring bars for a lathe. I have more pic if you want to see them. I may even post a build thread, if I can figure out how to convert autocad dwgs to pdf. Mike
http://db.tt/kKkrDDKG
My home made feeder
Can you post some specs on that hydraulic motor? Also what is the ideal rpm for line boring? I suppose that all depends on the conditions? I was pricing line boring machines from Climax and York and one thing that was neat about the climax is the ability to have the power head in the middle of the bar between two holes getting bored is that a possiblity to make a hydraulic powered one with that capability? Thanks Jerry
Jerry You may want to start your boring bar drive head design my first deciding on the optimum bar RPM for the type of work you are doing.Then look at how the hydraulic motor will turn the bar and at what reduction ratio. On a through bar drive head you can connect the motor by gears or belt drive. For general medium size bores you may turn at 0 to 150 RPM then calculate the hydraulic motor speed based on your gear ratio. If you power the motor with say a 5 GPM basic fixed displacement pump you will then select a small orbital type motor to turn at your target RPM. There is a wide displacement selection of these motors from many manufactures. You bigger challenge will be designing a good positive variable speed feed system.
LOOKING GOOD WILL DEFINATLY KEEP WATCHING THIS ONE thought about this many times myself
rjmitchell thanks for the reply I am in a shop where most of the stuff I learn either on my own or by talking to somebody else so this forum helps me out a lot! I got some bores I need to machine and the cost of a York or Climax isn't really in the budget right now and I enjoy building mine own equipment if I have the know how and the time to do it and maybe this isn't right but it looks like that a hydraulic driven boring machine would be a more solid and capable machine than an electric or not? Is there a valve that I could put inline that is variable with a knob like a electric variable valve so I could control the rpm and feed on a line boring machine? Or does that not work? Just some things I have been thinking about! Once again thanks for the help!!! Jerry
Jerry If you are doing big bores say 8 inches and up the hydraulic design can be built to run slow and still have very good torque when running a large displacement hydraulic motor. If you are doing 3 to 4 inch bores the electric will do just fine. The good way to control the rotational motor speed is with hydraulic power pack using a variable flow piston pump or a fixed displacement pump run by a variable frequency drive electric motor. You can run an in line flow control valve however they tend to create a lot of heat in the hydraulic system. If you are on a tight budget go electric 2 speed variable speed motor. Check out http://www.csunitec.com/drills_drive-units/slow-speed-electric.html I hope this will give you some ideas. Ray
They look like good drills. How would you be hanging onto that one in the pic with a 1 1/4 drill in it. Have a paramedic standing by
By all means, I don't mind the hi jacking! I get great inspiration from here, or else I would have never started mine. I know that there are many factory built units out there but I just don't have the finances to buy them!
I was wondering what your hydraulic power units looks like to run the hydraulic motor, if its electric motor driven how large of motor is it and what pressure does the pump put out, sorry for all the questions, this has caught my interest. I have two metal lathes and have always wanted a portable boring bar setup. Also how do you guys weld up the worn holes, with wire or stick.
Sorry for the slow progress, I'm doing it in between every thing else that has tom happen around here... Got the first set of alignment cones turned, used cast since I had it laying around.
It is aprox 5 cu inch per rev orbit style motors get them from surplus center
231 cubic inches in a gallon. So for ~150rpm, a 5 cu in motor would need 3.25gpm. Hp=gpm x psi /1714. Don't forget parasitic loss when sizing a power source.
I have to make a set up for doing a run of smaller hole around 30mm. Seen that some members make their own bar and other item to help. Could I use mag drill set up as the drive and feed unit as all the bores are small. What the members feelings? What do the members use when making your boring bars, I was going to use new hydraulic rod. Is this ideal or do I need something better. As this thread as given me the wake call, to push my self and make some of the equipment I need
many of the boring rigs that you see use the mag drill for feed, I may end up doing that myself. Right now it appears that hydraulic is the cheapest way for me to proceed. As far as boring bar material, I used 4140 because we felt that was our best bet.
What diameter are you going to make the bar? For 30 mm bores I would assume around 20mm? Even then you might have to die grind a bit to get that back into a welded bore. For bearings you can buy self aligning roller bearings with an outer holder that has a tag on it that you can bolt to a mount.
Here's a mag drill set up I use http://i864.photobucket.com/albums/ab208/parkrapids/1129121516a-1.jpg
got the mount pads cut out! bearings are in, last thing is to build a power supply!