Smokin a 1 1/8" Spade bit after 10 holes!

[HeadRusch]

Welp, that MDF is evil, evil stuff.  Bought a nice 1 1/8" Spade bit.....going through lexan then down itno 3/4" MDF.

The damn thing has pretty much stopped cutting now unless I freakin really lean into the sucker.
*Sigh*.  Does this MDF also stop artillery shells, perchance???

I gotta get a hole saw instead methinks...

[anthony691]

Welp, that MDF is evil, evil stuff.  Bought a nice 1 1/8" Spade bit.....going through lexan then down itno 3/4" MDF.

The damn thing has pretty much stopped cutting now unless I freakin really lean into the sucker.
*Sigh*.  Does this MDF also stop artillery shells, perchance???

I gotta get a hole saw instead methinks...

I can say that plexi dosn't really try it too hard. Maybe you should let it cool off between holes? (Mine melted a bit, it didn't wear out)

[HeadRusch]

Yeah, I guess...its just man....this is sloooow going with the spade bit..my arms are tired from applying pressure.

I've always lived by the mantra "Let the tool do the work" but this is really slow going....I might pick up that hole saw just to try it out...

[Gopherboy]

Hmmmm.... Conversely, I tried a both a holesaw and a spade bit and rate the spade bit head and shoulders above the holesaw. Of course, it was not an expensive holesaw but the spade bit still wins out.

I found that the holesaw burnt the inside of the hole, whereas the spade bit went through as clean as a whistle.

Even if the spade bit did get too blunt to finish the job, I would just buy another. The way I see it, a holesaw decent enough to do the whole lot would cost me about $50 (au) but the spade bit is only around $18.


gb.

[skirge66]

well I used a cheap holesaw...it was no where near, and i mean not even in the same ballpark as $50...maybe $10. it does burn mdf while it cuts, I just did each hole in three goes cleaning the bit as i went...my holes came out perfect, with a hole saw you would have to be a complete idiot to not be able to get perfect holes everytime. I personally wouldn't use a spade without a drill press or at least a drill with a level, just my .002

[paigeoliver]

$50 Au is like $25 American.

I ruined a holesaw made to cut metal just cutting two holes in a metal panel. Total waste of $30.

[skirge66]

but it's not about drilling metal...it's about drilling mdf with plexi... I drilled over 50 holes in 3/4 mdf with no problem...could probably drill many more as the saw is still in perfect shape.

actually $50 aussie dollars is about $33 usda, which is more like about 3X what i paid at home depot maybe $30 for a metal hole saw...not wood




http://www.homedepot.com/prel80/HDUS/EN_US/diy_main/pg_diy.jsp?CNTTYPE=NAVIGATION&CNTKEY=market%2fpg_zip_code.jsp&BV_SessionID=@@@@0359170313.1052720578@@@@&BV_EngineID=ccckadcifjhfghdcgelceffdfgidgng.0&search_text=hole%20saw&DRC=4

[ErikRuud]

MDF can be harder on your tools than regular wood do to the adhesive that is used in manufacturing it.  It creates more heat that plain wood. Excessive heat is bad for sharp edges.

You are probably drilling at too high of an RPM.  Your bit will probably last longer at a slower speed.

By the way, Spade bits can be resharpened. If you have over heasted it to the point that it has discolored then it is probably shot.

[MrArcade]

If you are drilling 1 1/8" holes in wood, look for a Woodeater bit. They last for many holes.  They are not as precise as a forstner bit ( I have never used a forstner ), but they work fine for me for button holes and the joystick center hole.

I get them at Ace and have found them at Wal-Mart too.


Here is a link to the manufacturer:
http://www.vatool.com/Catalogs/bodytemps/202.asp?PSubName=DRILLING%20PRODUCTS&PSubNum=202&PFamName=WOODBORING%20DRILLS&PClassNum=2020307&UClassNum=48&UClassName=Wood%20Eater%20Wood%20Boring%20Bits

[HeadRusch]

Good tip.  Yeah, yesterday before I punched through the last few holes I was trying to find my metal files, trying to put a new edge on the thing.

I didn't blue the metal but I think I was drilling at too high an RPM and that fried the bit....right now if I can't find my metal files I'm writing the bit off....I'll invest another 5 bucks and be more "careful" next time.
The 3" hole Saw however cost me $25 bucks between it and the mounting apparatus..thats for cutting the fan holes for my PC case fans I'm mounting.

I love a project that forces me to buy new tools

[VMJ Team]

Whether you are drilling, cutting or sawing...protect your tools! All cutting bits and tools should be used with the proper cutting liquids.  The cutting fluids will act as a coolant, it's also a preservative (on wood), it will make cuts cleaner and easier, and most of all...will make your bits and blades last 3 times longer.

I get all of my woodworking supplies at Rockler www.rockler.com.

[Gopherboy]

Good point CyberPunk - proper cutting oils are a great idea and not too expensive either.

I think the main prob with a saw bit (esp. with mdf) is that it only cuts out a groove, not a hole. A spade bit, on the other hand is like a really big drill bit (ok - I am exaggerating but you get the point!)

The saw bit will see more friction and less cooling than the spade bit - it is that simple. This is also because mdf is soft and made of sawdust. When you cut it, it clogs everything, including the groove you are making with a holesaw! I find that a holesaw works better on hard, brittle surfaces (like a melanine top) but poorly on soft surfaces. Vice-versa for spade bits, which make a mess of a melamine top!

And, (once again, conversely,) I am happier using a spade bit without a drill press than a holesaw without one. The way I see it, the spade bit allows a little margin for error. With the holesaw, you have to keep the bit at a perfect 90 degrees to keep the cut smooth. If not, you are rubbing against the wall of the groove and that = more friction, which is not good.

In short, I think that this hobby attracts lots of different people, with different skills, but the one thing that seems most common to be lacking is a good selection and knowledge of woodworking tools. For the average person who is buying a bit specially, and only for this project , I suggest the spade bit. It is more forgiving and much easier, and to be perfectly truthful, you would have to be a bit of a wally not end end up with a perfectly usable, clean cut and evenly spaced hole. Using only a home drill and no guides or presses. (And no oil either.)


Anyway, that, as I say, is how I see it - all it takes is a little common sense, patience and care, not necessarily expensive tools. A lot of people recommend a plethora of expensive tools, but to be honest, the most important tools are common sense and patience. Choose the right tool for the job of course, but there is no need to go out and buy so many things for a small project like this.

gb

[Brax]

When going through MDF you really need to take your time and let the tool cut. Too much pressure and too fast of a speed will burn like crazy. It will also dull your bit in no time! So even now if you use the proper pressure your bit may be too dull.

With practise you can feel if your bit is "biting" properly and apply the proper pressure. You'll be amazed at how easily it will zip through when you get it right.

Another possibility it that you have a cheap spade bit with a poor cutting angle. Drill bit sets are notorious for this. It's possible your spade bit was off as well.

I took my cheap (brand new) set of drill bits into work to let our machinist look at them. He could tell that every single one of them was off. Now my 20 dollar drill bits have the equivilent of a $100 dollar sharpening job! hehe It was night and day though. They cut SO much better now!

[mj147]

First off let me just say, im just a novice when it comes to working with tools and woodworking. But recently I have used both cheap spade and hole saws from Home Depot ( 9 dollar bits) on my panels.
In both cases I was very pleased with the results as both gave smooth cuts. I used the spade on 3/4 Birtch wth no problems and the hole saw on a metal and plexi panel ( i did clean the bit after cutting thro the lexan and let the bit cool between cuts). Both were drilled by hand using a 14 volt cordless drill. For ease I always drilled a small pilot hole and everything came out lined up well. Both bits still cut as good as they did when they were new. I think since im using a cordless drill I dont get the high rpm the corded drills get and therefore prolonging my bits maybe?


Just my experience

mj147

[Zakk]

Why not try a 1 1.8" forstner bit? I personally use a hole saw for plexi and metal, but the forstner for wood, plywood and mdf.  They're not all that expensive, and you can usually fine single bits on sale.  Also, if you have access to a drill press, it makes thing much easier, you don't have to grind down on the bit, just let the press do the work.  If not, here's a link to a quick jig you can make to drill nice straight holes.  Hope this helps a bit!
http://www.woodworkingtips.com/woodtips/wstip03.html