Magnetic Drill Press

[m3a1]

Gents,

Does anyone have any hands on experience with a magnetic drill press? I'll soon be needing to drill some long-overdue holes in the farmer-armor on my half track (just mild steel...not real armor plate). I've learned this much....the sky is the limit where purchase prices are concerned. Rentals, while moderately reasonable in cost, will just add the to expense if what I end up renting isn't capable enough and yes, most of this work will be conducted on a vertical piece of steel.

Tell me what you know.

Cheers,
TJ

[lpcoating]

We have mag drills and sluggers at the shop. What diameter holes are you drilling and how many?

Guy

[rickf]

Mag drills are THE tool to have when you need to drill large holes in steel plate, especially when it is above your head or in a place you can't get behind the drill. Or if it is really thick steel and the hole has to be precise. All that said, two things to keep in mind with mag-drills is 1, you get what you pay for and 2, you need a good clean flat surface of real steel at least the size of the magnet and at least 1/4 inch thick. I would rent if unless you are going to be drilling many holes over a long period of time. A good mag-drill is well over a grand.

[Hambone]

I sold the Jancy brand for many years, works great as long as you have a thick enough base metal so the magnet will hold. You have a couple options, a twist bit adapter is available for these drills which will able you to use the twist bits, they were designed for slug hole bits which allows you to remove much less metal, much faster cut. When using slug bits, you will need a centering pin, these pins will cover several sizes of bits, so you don't have to buy a different pin for each size bit. The bits are a little pricey but can be resharpened, one minor slip of the drill will break a bit instantly, that's why a good base is a must, constant lubrication is a must, we could cut a 1" hole thru 1" metal in 15 seconds, you can countersink and tap holes with them also.

[m3a1]

Well, I'm going to be drilling probably about 30 holes. Off the top of my head they're 3/8". Then, countersinking them for the typical half track armor bolts, where necessary.

The steel plate is 1/4" thickness... perfectly clean, without corrosion (and painted). Is that thick enough to get a good hold with the magnet? What power on the magnet would you consider to be the absolute bare minimum?

At the corners there are angle iron joiners that are nearly 1/4"...so let's call that a 1/2" drill depth.

I don't know the first thing about those fancy bits but 3/8? seems rather small for anything other than a typical twist bit....or am I wrong?

Cheers,
TJ

[rickf]

I would think a smaller mag-drill would work fine for that as long as you have a flat surface to attach it to. Like Hambone was saying, they were mostly for LARGE holes. I always used twist drills but I was using 1/2" TO 7/8" in truck frames.

[bazookajoe]

Be sure to tie it off so when somebody kicks out the cord it doesnt fall and break,...i have a milwaukee and have used it for years...love it.

[Hambone]

I think 7/16" is the smallest bit you can get in a slug bit, make sure if you rent one it comes ready for twist drills, invest in good drill bit, mag should hold fine on 1/4", not as fatal on the pocket when using twist drills.

[m3a1]

Proper hole placement is going to be a top priority and consider trying to do 30 holes or more without error...or the issue of fouling up bits because you're getting tired and off angle. That gets expensive really fast. I'm willing to bite the bullet on this if necessary but, the expense of rental is rather exorbitant. It ends up being about $100/day unless one is clever enough to rent over a weekend or up against a national holiday. Might just as well get something I can keep and use later for my money, even if it costs more money.

Our local United Rentals doesn't have one on the shelf. I'll see if they can bring one up for me to have a look at it....or go to wherever it is in San Antonio to look it over.

[Hambone]

Might want to try your local welding supply, we rented them out of our store.

[svramselaar]

hi

i used them several time`s to drill holes at truck chassis
if it has a electric magnet we alwais take a cable to hold the drill in place for safety
if the power is from your electric system the magnet has no power and the drill wil fall to the ground

george

[lpcoating]

Will you be able to use a transfer punch for hole layout accuracy?

Guy

[m3a1]

Yeah, I'm going to use a transfer punch to locate the brackets that need to be added (I'm mounting up some luggage racks to the back of the half track to disguise the farmer armor) and then there is the matter of all the armor bolts that (were this properly constructed in the same manner in which the half track armor was meant to have been held together) would have served to hold the back panel on. Right now it's just a big, empty sheet of metal that was welded on and it looks pretty awful.

I have a bit of wriggle room on luggage racks in terms of what goes exactly where because these units started out as field mods and quickly were adopted as items manufactured stateside. Photos of some half track pilot models show luggage racks already installed. Returning to the matter of my particular half track, which is a very early production model, having everything level and evenly spaced is the primary goal.

As to the matter of locating the placement of the armor bolts I was planning on using some strap steel to make a template. Better to make my mistakes there, than on the half track.

We do have a local welding supply so yes I suppose I ought to touch base with them and see what they have to offer. Right now it's just plain COLD and we got a light dusting of snow last night which didn't last long. So this is a good day for errands.

Cheers,
TJ

[m3a1]

I did go down to Harbor Freight today and pick up a 28 piece transfer punch kit for $10.98. 3/32" to 1/2" in 1/64th" increments. For my purposes a set of this quality will do. Low end, to be sure, but I'll be using permanent marker as a substitute for bluing dye. I'm rather sure I can get through 30-40 holes but even if I have to go get another set it's still going to be less than 1/2 the expense of a better set. Will follow up the initial mark with a center punch of far higher quality so all should be well.

I also picked up a 4' aluminum straight edge to assist in the matter of laying out the line for the holes and an 18" magnetic tool holder which should come in handy during the work. Too bad that straight edge didn't come in steel. I have tons of clamps, to hold everything just-so.

I'm seeing plenty of new and used units on eBay. Among them Yancey, Hitachi, Hougen, Milwaukee, Slugger, Portomag and a host of others. There is a Rockwell I'd love to have but seller only offers free local pickup.

I also watched several youtube videos posted by an independent party testing some off-brand stuff Bluerock $400 which came with a set of bits & had quite a bit of runout (I guess the bits are an apology for the other problems) and also C S Unitec MABASIC200 Magnetic Drill, $600 and change which is (reportedly) made in Germany, seems far better engineered, runs very true and is at least as powerful as the Bluerock.

$600 seems to be the threshold number.

Any further thoughts? I'm rather 'on the fence' at the moment.

Cheers,
TJ

[rickf]

The one I had was a Milwaukee if I remember correctly, I do know I paid around 1500.00 for it in the early 80's so figure that price nowadays.