Problem drilling holes in L3800 grill guard

[m32825]

I'm working on adding front supports to my canopy to beef it up. TripleR was my inspiration, the plan is to attach them to the grill guard like he did here:

TripleR Grill Guard

There's something I need to learn here because I'm breaking my drill bits trying to drill through the guard.

I have no problem drilling holes through mild steel, so I'm guessing the grill guard isn't mild steel. How do I drill holes through it? Educate me and my drill bit collection will be eternally grateful, thanks!

-- Carl

 

[skeets]

I have never seen anything that hard in a grill guard,, ya must a got a gooden,,lol,, Drill slow speed, lots of oil, and dont try to push the bit through
let it cut and do the work
And you might want to drop into Lowes or Homedepot and pick up a drill doctor,, that thing has saved me a bunch on reshaped drill bits

 

[bxray]

Hi M32825,
You need to use drill bits that is not a brad point for metal.
Brad points with the flat part is for woodworking as it keeps it from drifting.
Get a new, sharp metal cutting bit.
Plus redrilling a hole to larger size will be difficult.
Go slow and keep it oiled and let all parts cool down.
If the bit tip gets hot it will cause it to dull or break.
And when it breaks through it will snag so watch your wrist.


Ray

 

[m32825]

Thanks for the tips, guys, problem solved!

Other than going too fast, pushing too hard, cutting dry, and using the wrong drill bit it turns out I was on the right path all along!

-- Carl

 

[Daren Todd]

Yup, like the others stated. Low and slow with a good metal bit. Get some marvel mystery oil or good tap oil for drilling and keep it lubed up. Start hearing the bit start to squeak or squeal it's time to add a little more oil. Had a machinist show me that trick.

 

[Tooljunkie]

Thanks for the tips, guys, problem solved!

Other than going too fast, pushing too hard, cutting dry, and using the wrong drill bit it turns out I was on the right path all along!

-- Carl

Had to laugh at this.
And you arent the first one on the learning curve.

If you can find MORSE Cutting fluid it would make you look like the drilling overlord. I have never seen anything better. Just did a quick search, doesent exist anymore(ozone depleting substance) so that plan is out the window.
Glad you got them drilled. Drilling can be difficult at times.

 

[ShaunRH]

Any cutting fluid is better than none, also, working your way up in size by doubles is a good idea: ie, 1/8" pilot, 1/4" mid, 1/2" final... like that. This way you aren't stressing your bits or your drill as much.

I use a sulpher based heavy cutting oil in a trigger oil can and keep the bit wet. I also use a very slow turning D handle drill.

 

[PHPaul]

IANAM (I am not a machinist) but I've always been taught that the proper drill, properly sharpened, used once is a MUCH better approach to large holes.

Starting small and working up puts all the stress on the outer wings of the cutting edge and is much more likely to result in an overheated and dulled, if not broken, drill bit.

Lubrication and drill speed are important whenever drilling metal and critical when dealing with hard metals.

In general the larger the drill, the slower the drill speed: source

 

[Dieselbob]

What also works good is to drill a smaller hole and then use a tapered reamer to get it to the finish size. The only problem is, good tapered reamers are expensive. I have a couple, but not as many as I need.

 

[ShaunRH]

IANAM (I am not a machinist) but I've always been taught that the proper drill, properly sharpened, used once is a MUCH better approach to large holes.

Starting small and working up puts all the stress on the outer wings of the cutting edge and is much more likely to result in an overheated and dulled, if not broken, drill bit.

Lubrication and drill speed are important whenever drilling metal and critical when dealing with hard metals.

In general the larger the drill, the slower the drill speed: source

I am referring to hand drilling here but...that entirely depends on your finished size and the hardness of the metal.
Yes, with mild steel, you don't need to work your way up, but a pilot hole always helps and keeps the metal out of the bit point which is the least effective drilling area of the bit. The 'wings' of a drill bit, as you put it, are supposed to be able to handle the load and if they are dulling or breaking you aren't using proper speed, fluid or technique.

With a drill press, mill or other heavy/fixed implement, you can usually go final size as you won't drift as much as a hand drill.

In hardened metals, you will find that you have to work your way up or risk overheating the bit even with cutting fluid.

 

[Tooljunkie]

Was my understanding the best pilot hole is the size of the web. Thats the part at the tip. Slow and a proper sharpening with correct cutting fluid.

 

[tcrote5516]

I always start with a 1/4" pilot hole and then use a step bit to get to the size I want. The step bits are worth their weight in gold.

 

[ShaunBlake]

IANAM ... stress on the outer wings of the cutting edge and is much more likely to result in an overheated and dulled, if not broken, drill bit... Lubrication and drill speed are important whenever drilling metal and critical when dealing with hard metals... In general the larger the drill, the slower the drill speed: ..

I am referring to hand drilling here but...that entirely depends on your finished size and the hardness of the metal... a pilot hole always helps and keeps the metal out of the bit point which is the least effective drilling area of the bit...

Was my understanding the best pilot hole is the size of the web. Thats the part at the tip. Slow and a proper sharpening with correct cutting fluid.

Yep, yep, eezackly right!

The tip, properly sharpened, will drill, even solid metal. However, it has the least efficient cutting edge. Depending on the hardness and type of the material being drilled (I had to adjust because many materials present the same challenges as metal, if not as severe or noticeable), it's usually best to drill a pilot hole when the finish size will be as large or larger than 'F' or 1/4".

PHPaul nails the concept of stress on the 'Major Cutting Edge' (DHPauls' "wings"). As Shaun correctly notes, these are designed to handle that stress -- when, as PHPaul requires, the bit is properly sharpened and the appropriate lube and appropriate speed & feed are used.

In my experience (several years as a machinist, then CNC programmer), when a drill bit has been properly sharpened and properly used, the 'Chisel Edge' will require resharpening far more often than the Major Cutting Edge. That being said, I usually drove drill bits until the MCE began getting a little dull. (I *hated* hand-sharpening bits, and I preferred hand-sharpening than any of the jigs available in the shop in those days.)

Hope that helps.

 

[ShaunRH]

I always start with a 1/4" pilot hole and then use a step bit to get to the size I want. The step bits are worth their weight in gold.

Step bits are awesome as long as your metal thickness does not exceed your 'step' depth (and you have full control of the bit!)

Watched a guy try to step drill ¼" steel with a step bit that was only 3/16" deep per step and he wondered why he got a 'lip'.... I told him he'd have to take out the lip with a full width drill of the right size... no step. On the plus side I told him he could keep going with the step bit and be automatically counter sunk. We laughed at that.

 

[m32825]

I'm learning a lot from this thread, thanks for all the input. I'm going to get a drill doctor so I can sharpen dull bits. What is the best type of drill bit to buy for drilling metal like the grill guard?

-- Carl

 

[Daren Todd]

I'm learning a lot from this thread, thanks for all the input. I'm going to get a drill doctor so I can sharpen dull bits. What is the best type of drill bit to buy for drilling metal like the grill guard?

-- Carl

If you figure out how to work the drill doctor can you post back how to use it I picked one up at a yard sale that someone had bought and couldn't figure out how to work it. I ran into the same issue ended up putting it in a yard sale a couple years later

 

[PHPaul]

If you figure out how to work the drill doctor can you post back how to use it I picked one up at a yard sale that someone had bought and couldn't figure out how to work it. I ran into the same issue ended up putting it in a yard sale a couple years later

I have one that worked GREAT for a couple of years and then not so much. I suspect that the stone inside is worn. Also, I was seriously embarrassed by a guy I worked with that could free-hand a bit on a grinder and produce a better edge in 10 seconds than I could in 10 minutes with the DD.

 

[Daren Todd]

I have one that worked GREAT for a couple of years and then not so much. I suspect that the stone inside is worn. Also, I was seriously embarrassed by a guy I worked with that could free-hand a bit on a grinder and produce a better edge in 10 seconds than I could in 10 minutes with the DD.

Yup, the guys that work in the machine portion of the local fab shop are like that. They use a dressing tool on the grinding wheel, and a quick buzz buzz on each side of the drill bit and they are done I've gotten better at it on a grinding wheel. But after a while I tend to get them a little off center Then they go in the scrap bin and I just buy a new one

 

[Tooljunkie]

Hand sharpening drill bits is a challenge. 1/4" and up to 1/2" arent too bad for my weary eyes.
My lighted magnifier helps with the smaller ones.
Some days i got it some days i dont.
On my good days i sharpen a bunch of bits.
Chipped bits may as well be tossed, it takes so much to get them back into shape.

Everybody has a different approach to sharpening bits,so lets not go there. Youtube has many videos regarding this subject

 

[ShaunRH]

If you have the desire and patience, learn to sharpen bits. There's about a dozen things you have to do right to get the drill to work efficiently and cleanly. Get any one of them wrong and the bit either will not drill or will just immediately dull again. You have to learn and practice the techniques.

I have a sharpening system for drill bits and it's okay. It's akin to a drill doctor. However, a well dressed stone, training, some water and patience is all you really need.