Taiden
Taiden Reader
5/17/11 10:41 a.m.

Looking to pick up a die grinder from Harbor Freight. I'd use it for things like cleaning up the inside of old nasty tube before TIG welding, doing basic port matching to manifolds, and maybe playing around with DIY ported heads?

Just trying to figure out what I should be looking at for die grinder and attachments for these things.

Harbor Freight specific please because I have a gift card there. :)

93EXCivic
93EXCivic SuperDork
5/17/11 10:44 a.m.

I have used one to do a lot of grinding on our Formula SAE chassis. It has worked really well.

Giant Purple Snorklewacker
Giant Purple Snorklewacker SuperDork
5/17/11 10:54 a.m.

I have the basic straight and angle grinders they sell for under $20 each and they work reasonably well. They are greedy with the air though so if your compressor tank is small it will run constantly.

I did have to oil them both before they worked - and adjust the gear mesh on the angle grinder. It was too tight to spin freely when I got it home.

curtis73
curtis73 GRM+ Memberand Dork
5/17/11 10:56 a.m.

If you're porting heads, get an electric. Air die grinders can drain even the largest compressors, and they get ice cold. Mine gets cold enough that it frosts and I can't even hold it with leather gloves if I use it for long periods.

I got the cheapy $17 air die grinder at HF and its not bad. It spins like crazy, but doesn't have a lot of torque. Torque isn't high on the priority list, but its sometimes nice. Basically, the grinding requires HP - lots of speed and the bits do the work. But sometimes if you really need to dig into something, mine just stalls.

So, I went back and got the "pro" version. Much nicer, but much bigger.

As far as attachments, you'll probably want a selection of wire wheels. They sure do a quick job of ripping welding slag off and throwing red-hot slag into your eye. Get some carbide burr bits in varying shapes. They probably sell a set of bits, but that's one of the things that HF doesn't do well. Just don't be surprised when they don't cut much. I also got a set of grinding stones. They're nice if you need to re-grout, shape fiberglass, tile, or hardwood.

weedburner
weedburner New Reader
5/17/11 11:05 a.m.

It's well worth getting a good grade of die grinder w/ tight bearings. The cheap loose bearings in those $20 units allow a bit of chatter that will quickly kill the sharpness of a new and expensive carbide cutter. I have a NAPA pro series die grinder (appx $100) that looks very much like the cheap die grinder that i paid around $20 for. Look and feel is the same until you actually start removing some metal...

16vCorey
16vCorey SuperDork
5/17/11 12:13 p.m.
curtis73 wrote: If you're porting heads, get an electric.

Absolutely. If you decide to go this route, there's a cheapie China made one that is sold as a no-name and is also sold as a Makita. It looks like this: It's crap. There's a coupler inside that connects the motor to the shaft that's made of plastic and breaks very easily. I made my own after the first one broke and it worked alright, but even my home made couplers would start breaking. I also have one that looks like this: Don't get that one. It's WAY too fast. If you've got a cartridge roll on a 3" or 4" mandrel the off balance of the cartridge roll will just about immediately bend your mandrel to a 90* angle. And since it has an on-off switch that's not spring activated, when that happens you will probably lose your grip on it, leaving you with a die grinder with a 3" leg spinning at 25,000 rpm on you floor. That thing is freakin' scary and dangerous, and I don't scare easily.

I got this beast for porting heads, and it's nearly perfect, if not a bit heavy: It runs the perfect speed and has plenty of torque to just lay into it and let it eat.

benzbaron
benzbaron Dork
5/17/11 12:28 p.m.

I think you need to put a power transformer on some of these die grinders to mellow them out. I have a die grinder with a 3in rubber plug on the end and it puts out way too much power to be usable. Feels like you got a wolf by the ears when you fire it up. I mostly end up using a no-name hobby model but it seems the chuck is getting worn out. When I get to using it at high speed for an extended time the chuck will loosen up and throw the stone and holder across the room.

motomoron
motomoron HalfDork
5/17/11 12:46 p.m.

I have 3 in the air tools drawer:

  • An old Taiwanese cheapie I've had forever. Ported my first race motorcycle heads, wore out a number of free compressors with it. I keep an beat-up 3/8" cylindrical carbide burr in it.

  • A newer Chinese Kobalt branded one bought on blowout at Lowes. Has a safety on the lever which is a pain. I keep a 3" 3M Roloc drive in this one with an 80 grit disc.

  • Another $25 Chinese one with a 3" 3M Green Corps cutoff disc.

I generally only grab these tools when there's not enough room for a 4" angle grinder, of which I have 2 Makitas in the next drawer down. One has an 80 grit flap wheel, the other a cutoff wheel.

1988RedT2
1988RedT2 Dork
5/17/11 1:17 p.m.
16vCorey wrote:
curtis73 wrote: If you're porting heads, get an electric.
Absolutely. If you decide to go this route, there's a cheapie China made one that is sold as a no-name and is also sold as a Makita. It looks like this: It's crap. There's a coupler inside that connects the motor to the shaft that's made of plastic and breaks very easily. I made my own after the first one broke and it worked alright, but even my home made couplers would start breaking. I also have one that looks like this: Don't get that one. It's WAY too fast. If you've got a cartridge roll on a 3" or 4" mandrel the off balance of the cartridge roll will just about immediately bend your mandrel to a 90* angle. And since it has an on-off switch that's not spring activated, when that happens you will probably lose your grip on it, leaving you with a die grinder with a 3" leg spinning at 25,000 rpm on you floor. That thing is freakin' scary and dangerous, and I don't scare easily. I got this beast for porting heads, and it's nearly perfect, if not a bit heavy: It runs the perfect speed and has plenty of torque to just lay into it and let it eat.

Did anyone else feel like they were reading "Goldilocks and the Three Bears" when they were reading this?

foxtrapper
foxtrapper SuperDork
5/17/11 1:31 p.m.

Pay attention to your stones and cutters. Cheap junk isn't worth buying. It'll make the best grinder work horribly.

Zomby woof
Zomby woof SuperDork
5/17/11 7:12 p.m.

A cheap grinder will work for what you want to do. Get some carbide burrs, some flap wheels, and some sanding drums.

I port heads everyday and use a Dynabrade air die grinder. It usually only gets a little cold in winter, and will cut all day long. The only problem is, it's $250.

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