Which bit to drill WM bed rails?

[srt]

Mornin'

I've bought a pair of the retrofit type toe boards for my vintage LT-30.  According to WM's Form 237B, I'm supposed to drill some 7/8" holes in the bed rails to accommodate the toe boards.  I don't have a metal cutting bit that large.  I don't know how much $$$bit$$$  I need to drill this steel.  There are about 50 bazillion bits on ebay - ranging from junk to probably the really good stuff.  I'm not sure I could tell the difference.  I have a 1/2" Millwaukee rt. angle drill to drive the bit, but don't know which ones to get.  Are the rails hardened?

I'd like to buy a set of bits to go from 1/2 to 1" to drill steel.  Could someone recommend a reasonable set for me?  Don't need the best, since I won't use them often.  However, don't want junk because I will use them more than once, and will keep them for a long time.

Thanks!

[Fla._Deadheader]

I've seen several people use those "Unibits". They go from a small size to a large size, all in one piece.

  I'm not a fan, don't have one, BUT, they sure seem to work, IF yer drillin through 1/8" or so ???  Can't drill through a piece of box tube, more than 1/2" or so, without drilling from both sides ???

[Raider Bill]

Those unibits work pretty well for general work. I keep one in my apron pocket. If anything needs special drilling I have a drawer full of regular bits but you can't beat reaching in the pocket for speed on a job.
I know the come in some bigger sizes.

[Gary_C]

Drilling holes over 1/2 inch in steel tubing or other relatively thin wall steel can be difficult unless you can use a drill press. I would recommend you buy a good hole saw bit and use that to drill those 7/8 holes.

If you still insist on buying a bit set, you will need a reduced shank set and they will not be cheap. The better ones have three flats on the shank so the chuck can hold the bit without spinning. They will usually be found in industrial supply houses.

[JimBuis]

If I were to invest in a set of bits that big, I'd be sure to consider HSS (high speed steel).

IMHO,
Jim

[Dan_Shade]

I prefer a drill press or an air drill for holes that large.  an electric drill will wrap you up and try to make you a gymnist when it catches.  a hole saw may work, but you may dull a few before you get all the way through.

you may be better off to find a small shop where a guy doesn't care to make much money and have him drill the holes for you for $25.

[Tom]

I can't figure out why you need to drill 7/8" holes, unless it is for the head of the bolt to pass through to just one side of beam or for Hydraulic lines to pass.  Just curious, could you tell me the reason for the big hole?

[Fla._Deadheader]

I've noticed those Unibits don't grab near as much as a twist bit. Yer gonna need a 1/2" chuck drill motor, and they all come with that "other" handle, for the torque??

[TexasTimbers]

Try a true cobalt amalgamation (5% cobalt minimum) bit. Cobalt or titanium nitrite coated bits are cheap and no gooderer than HSS it's a sales gimmick.
HSS is good if it's good HSS. 135° split plate versus 118° is better as it does not generate as much heat. SKF Dormer is great quality. Viking is pretty good Vermont American HSS is decent. A bronze finish is great bronze resists heat well. HSS needs to be at least 18% tungsten to be considered good HSS IMO depends on whose it is and the direction of the plate. Use a lubricant. The bigger the bit the slower you want to go. If you are doing it right i.e. correct RPM and pressure you should be "making steel wool". Making chips and making smoke means the RPM/pressure combo ain't right.

The Machinist Handbook has much of this info and is real handy.

Friction is the enemy of the bit. You lose the temper and it gets dull. Remember friction is the enemy. Click your heels together 3 times and say "Friction is the enemy. Friction is  the enemy . . . . . . . . . "

[logwalker]

What you need (if it will fit), is a magnetic base drill. These use end mill cutters and go through the hardest steel like butter. I used one to drill my frame rails on a Kenworth truck to shorten the wheelbase. Really amazing tool. But you will need a few inches of room to set the base.  But like Tom mentioned it seems odd that you would need a hole that large. What does Woodmizer suggest for the project? Good rental yards have these drills. Joe

[srt]

Hey folks, 

I just wanted to reply to my thread before I left town for the weekend.  Gotta get down to the farm and plant some corn.  My Reid's yellow dent seed just arrived, and there's a 3 acre patch that I'm going to plant.  Mostly for fun, but the justification is so I can feed the steers.  Also gives me a reason to fix up the one row corn picker and build a crib.  Too many fun things to do!!!!!!

Anyway, the directions for the 7/8" hole come straight from WM.  Their form 237B that shows how to install the retrofit toe boards on the early LT-30 says to drill the 7/8" holes.  Don't have time right now to break it all out again and do the common sense check of the directions.  That'll have to wait until after me and the Moline 670 have spent a few hours together this weekend.

I'll report back next week.

I may very well just take the WM into the local NAPA guy to drill the holes.  They have a good machinist there who's not afraid of working on stuff other than engines.  He does my bearing work on jointers etc...

[Nailhead]

I agree with gary c
Use a 7/8" hole saw. Just drill a 1/4" pliot hole and if the piece is flat, drill another 1/4" hole so that the outer edge just hits the circumference of the 7/8" hole. Use plenty of cutting oil to flush the chips thru the outer hole. If the rail is round, you don't need the outer hole as your only contacting the metal in two placed at a time 180 degrees apart. You still need to use plenty of oil. I have drilled holes in 1" plate this way thousands of times, just use two outer holes on thicker material.

[Bibbyman]

 

If you got enough will there is a way...   :D 



How perfect a hole does it have to be?

[Quartlow]

Invest in a good set of cobalt bits like Kevjay described. you may not use them often, but when you do they work.
I hate trying to drill a hole with a junk drill bit

I prefer a drill press or an air drill for holes that large.  an electric drill will wrap you up and try to make you a gymnist when it catches.

And why is it when it catches do we never let go of the trigger right away?  :D

[fstedy]

If you're drilling Rectangular or round tubing or light structial steel 3/8" or under web thickness go with the hole saw it wont grab on you when you break thru and it gives a nice hole with a hand held drill. Go slow about 300 rpm with a 7/8 saw will give you about 70 surface ft per minute which is how cutting tool speeds are calculated. Thats a good rate for mild steel which structial steel is. Keep a lot of pressure on the hole saw as this creates a larger chip that will carry heat away from the material and tool. Oil will also help with freerer and cooler cutting. Milwalkee, Lennox and Starrett all make a good saw. Don't pre drill as the pilot drill in the hole saw helps give you a nice tite guide for the saw thats why they have it there. Center punch the hole center that will keep the hole lined up for you and make starting much easier. You shouldn't have any trouble at all drilling these holes take your time lay it out and check the locations. Remember slow drill speed and high drill pressure will keep the heat down which is what destroys tooling.