Boring with a mag base drill

I was a machinist for seven years war and horizontal bar now and vertical boring Mill and lathe I have a crazy question I need to bore some holes in the back hoe all that I have is a big Milwaukee mag base drill mt3 variable speed weighs 70 pounds swivel base. Here's what I want to do with that I need to borrow out some Outriggers on my backhoe for some new bushings I'm going to buy a Criterion head but the only problem is I don't have power feed you think I'm crazy to try to do it or hand no power feed if I go so slow .thank you for any input

If you are not looking for extreme accuracy, it probably will work. Don't know how good the spindle / quill is on your mag drill or how you will hold the boring head? As far as feeding it slow, I wouldn't be afraid to try it.

Hi dufftrucks:
Everything is going to depend on how well you can keep the boring forces from popping the mag base off the job.
I'd find a way to line bore them even if you have to tack weld some temporary bushings onto the machine wherever you can.
Also I'd avoid single point boring with the mag drill; even two cutting edges in the cut simultaneously will balance the forces much better and three will be better still.

Jerry up something to take the loads and then just use the Milwaukee for power to drive the bar.
If you look at portable line boring equipment like what Climax and others offer for inspiration, you should be able to come up with something that works without too much pain.

If you can't do that, I'd look to see if there's a Hougen rotabroach in the diameter you need.
They're designed to run in mag drills.
I believe you can buy them in 1/16" diameter increments and they go up to around 2" diameter.
You might have to weld a temporary pilot pin plate into the existing hole to get it started, but you'll have a much better chance to do a decent job without risk.
Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

These guys built a very simple secondary bearing plate for their big ass mag drill. I would at least to that.

it looks like they weld the channel / bearing plate in place (which is typical) then center over it with the drill and this will prevent the drill from seeing much radial load


Beck Equipment

Here is one.

Portable Line Boring Machine Tools for Heavy Equipment Bore Repair

And a discussion about making one.

You may have to register on the site to see the pictures.

Line Welding & Boring Cost?

I think you can buy the line boring bars, Maybe from McMaster-Carr, I forgot the source.

I spent my entire apprenticeship field machining and doing shit like this with mag drills and portable toola, it can avsolutely be done.

You need a guide plate on the drill end, and another on the tail end, possibly more if theres alot of bores in line.

Your line bar needs some broached slots or simple drilled and croas drilled/tapped slots if you are in a hurry. If you aint got a fancy climax head and its just a milwaukee mag, i strongly suggest pull boring (start at the bottom and pull it out) and HSS toolbit a Rex or MoMax should do it.

Some good spring calipers to measure with, and a steady hand.

My mag drill has a 2MT spindle so I can put a regular drill chuck in when I need to.

There are lots of kinds of hole cutters. The one in the pix below came from Boeing Surplus back in the day. Cut a nice clean hole. The tank I was cutting into was thin (3/16") but the cut was solid and would have gone much deeper had I needed it to.

metalmagpie

I have done quite a few jobs with a mag drill and boring bar. I built some tapered cones to center my bar, then weld the bushings in place. I ground the cutters so they would push back or at least be neutral, you don't want them to grab and pull in. Then feed nice and slow. You can weld up run out bores and bring them back to stock or overbore and bush them. OH, last thing, make sure you have the drill anchored and suspended. Losing power when you have a hand under one of these things will ruin your day!!!