drilling out rivets????

I am removing hardware from my old, bent, mast and crossbeam. When I was trying to drill out the rivets I had a lot of trouble, broken bits and ground down bits. I still have more hardware to remove. What kind of drillbit and size do I need to use to cut through the monel and stainless rivets? I saw it on a post somewhere before but now I cannot find it!! If someone could help I would really appriciate it!!
Thanks,
John

I know this probably won't be much help in selecting a bit size, but are you using any cutting oil/ fluid. It sounds like you might be. If you're not the bit will get super hot and will loose all of its hardness and cutting ability.

As far as bit selection, I always start smaller than I think necessary and then choose a larger bit if necessary.

Use a 7/32" bit to just take the head off, then drive the tail through with a 3/16" punch.

Bosch makes cobalt steel bits that last longer

(that set's from toolbarn.com - the bit alone is about $1.50)

Use a shot of WD-40 to lube the bit when you drill.

Thanks, for the help, and no I was not using any cutting oil, I guess that is why my bits did not work more than a couple of times!
So the cobalt bits work best?
Thanks, John

Putting a new cheek block on the mast.How important is it to use rivit caps?

A good source for tooling is

http://www.mcmaster.com

I buy most of my machine shop supplies here for work. They have all kinds of different materials for drill bits and bits with different coatings. They also have cutting oils that are better than WD-40

_________________
Nick

Current Boat
In the market
Previous boats owned
'74 Pearson 30
'84 H16
'82 H18 Magnum
St. Louis, MO

You should use lower RPM on the drill along with good bits.

The rivet caps are what make a water tight seal. Use them.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

uh plz plz plz don't use wd40 like the earlier poster suggested. drill bits can get very hot when drilling thro metal.

hot drill bits + highly flammable liquid = very very bad combo.

While WD-40 certainly isn't the best machining lubricant, it's unlikely to catch fire when you're drilling off a rivet head.

According to the MSDS for WD-40, it has a flash point of 134 degrees (flash point = is the lowest temperature at which a liquid or solid gives off enough vapour to form a flammable air-vapor mixture near its surface). It is not a "highly flammable liquid."

By comparison, gasoline has a flash point of -40 degrees.

I mentioned it because almost everybody has a can in their garage. I've been sailing and maintaining Hobie Cats for over 30 years (and drilled off a lot of rivets in that time) and I have never had WD-40 (or any other oil I've used) catch fire when drilling. Smoke, yes. Fire, no.

That being said, don't spray a hot drill bit with any aerosol lubricant. That's asking for trouble. Just a bit on the rivet head itself before you start drilling is fine.

This is not a sophisticated industrial process.

Well said... I have NEVER had WD-40 catch when doing "light" machin work, yes it will ignight in the arisol form but spray some on the ground and take a tourch to it and see iwhat happens. Its simply wont light unless subjected to continious heat + flame. WD-40 will work great.

I've even heard of using cooking oil in a pinch, but at less than $3 and at just about any hardware store I'd opt for the cutting oil.

As far as rivit caps go, you'd better use them on the mast. If not water has a direct path into your mast making it next to impossible to recover from a capsize. Remember after the rivit is pulled, it's nothing more than a hollow tube with flared ends.

Adam

I've had good luck removing rivet heads with a 4" grinder. Buzzs them off like a hot knife through butter. These types of grinders are pretty easy to keep in a steady position, but If you slip you'll have a nice shiner on your mast.

_________________
hobiejohn at earthlink dot net
Fleet 297

The 7/32 cobalt drillbit and the wd40 worked great, I drilled slowly and did not have any problems. Now I have to cut up the old mast and crossbeam and take it to the recycle company. Will a regular hacksaw work at cutting the mast and crossbeam? I have a jigsaw, do they make blades for jigsaws to cut metal?, and should I use the wd40 when cutting these up?
Thanks, everyone has been a great help!!
John

A hacksaw will work, but it'll take a long time. Your arms will look like Popeye's when you're done, though.

Sawzall with a metal cutting blade is the ticket. An electric miter saw (chop saw) with a carbide blade would work, too.

Don't need cutting lubricant with aluminum for what you're doing.

Actually, any electric saw with a metal / carbide blade will work. Just be careful of kick-backs.

John,

When will you be able to haul it up to Lake Stockton? I'm collecting bent masts and crossbeams for a project. We can do a little sailing too.

email me at

[email protected]

Also, I can put you in contact with three other Hobie sailors around the Springfield area.

Let's talk.

_________________
hobiejohn at earthlink dot net
Fleet 297