Measuring and drilling on a curve?

[BoonDockSaint]

HI!

maybe someone can point me in the right direction. I want to drill holes bigger toward the center then smaller as the rows go toward the outer edge.(to start) on the left half of one of these: (you know to make it go faster..hehe)

The raised surface to the left of the trim ring in the center, I'd like to evenly drill holes in a pattern akin to a set of bowling pins standing. The surface is curved. I want these as close to perfect as possible. I've been thinking of using pieces of paper taped together to make a template or bolt it on the bike and use a laser level I don't have to create a line.... I'm sure I'm over thinking this. suggestions?

Also, surprisingly, I've never drilled through a show chromed part. I"m going to have to use a hand drill on the bench I think because I don't see how I'm going to get straight on it with my homeowner craftsman drill press. Aside from using a center punch, is there anything else i should be aware of when drilling chrome? Sorry for the remedial questions, I started my "fabricating" way late in life...

Thank you!

 

[Kevin54]

Boondock......I like to stress to members to put a location in their profile so others can easier answer questions, but nonetheless.......Tape everything up real good, then carefully locate your holes, and make a pen mark. If you have a ***** punch, put your hand behind the piece as backup, then ***** punch your marks. Depending on the size, you ay be able to use just a centerdrill to pop your holes in. If a different size, for a true round hole, you would need a drill and reamer.
Or if you would want to ship it to me, I can put in some precision holes in on the mill I have, to any pattern you want, for only a few bucks, plus shipping. I've been doing things like that for close to 35 years. Turn-around would be a day on my end

 

[little d]

If ya want it done right and not have that home made look, ^^^^^ I'd take Kevin up on the offer, Laying out holes may be fairly easy, making several look symmetrical...Whole different world.

 

[larry_g]

In thin sheet metal you will have no end of grief trying to put holes in with a twist drill. If you only have a twist drill I suggest that you try to drill a hole in some scrap of the same thickness metal. A step drill is one tool designed for putting round holes in sheet metal.

lg
no neat sig line

 

[iajonesy]

I would also take Kevin's offer. A mill would give much better results than a hand drilled version. If you end up drilling them yourself be very careful with how you hold your work piece. Sheet metal will "grab" as the drill gets through the hole and can turn into a meat slicing propeller before you can say "ouch".

Mike

 

[BoonDockSaint]

Boondock......I like to stress to members to put a location in their profile so others can easier answer questions, but nonetheless.......Tape everything up real good, then carefully locate your holes, and make a pen mark. If you have a ***** punch, put your hand behind the piece as backup, then ***** punch your marks. Depending on the size, you ay be able to use just a centerdrill to pop your holes in. If a different size, for a true round hole, you would need a drill and reamer.
Or if you would want to ship it to me, I can put in some precision holes in on the mill I have, to any pattern you want, for only a few bucks, plus shipping. I've been doing things like that for close to 35 years. Turn-around would be a day on my end

Thanks for the quick response! I did as you suggested and added a little more info to the profile, I never really thought i'd be asking questions here, now there's no end to them! I do have a ***** punch, (had to look that up, I call it something else) and I'm going to try it the way you described. Based on the other replies, you must have a great reputation here!

I actually do have a center drill, but only one or two sizes. I'll have to see what a set costs. (My old toolmaker friend used to present me with things like that and say "you'll need this one day" hehe the day has come!)

I appreciate your generous offer. For now, I'm going to decline. I really want to do this myself and I have the sense that it's going to look like hammered ****..... I had originally intended to just cut the center out and make a "top hat" for the air cleaner and make something cool to replace the bolt that holds the cover on. That's going to be a hex bolt with some old wrench cut and bent then welded onto the bolt so it looks like the wrench is just hanging there. TMI, I know. Then I thought why not try some other things first if it was just going to get cut off anyway.

The stock AC covers for harleys are a dime a dozen so I"m not too concerned about screwing anything up.

Maybe you can answer another question. Do you guys keep all questions within the same project thread? As in, yeah, the holes look like ****, i"m going to cut the top and bottom halves of the cover off and need advice on how to finish the edges. That kind of stuff.

 

[Kevin54]

Thanks for the quick response! I did as you suggested and added a little more info to the profile, I never really thought i'd be asking questions here, now there's no end to them! I do have a ***** punch, (had to look that up, I call it something else) and I'm going to try it the way you described. Based on the other replies, you must have a great reputation here!

I actually do have a center drill, but only one or two sizes. I'll have to see what a set costs. (My old toolmaker friend used to present me with things like that and say "you'll need this one day" hehe the day has come!)

I appreciate your generous offer. For now, I'm going to decline. I really want to do this myself and I have the sense that it's going to look like hammered ****..... I had originally intended to just cut the center out and make a "top hat" for the air cleaner and make something cool to replace the bolt that holds the cover on. That's going to be a hex bolt with some old wrench cut and bent then welded onto the bolt so it looks like the wrench is just hanging there. TMI, I know. Then I thought why not try some other things first if it was just going to get cut off anyway.

The stock AC covers for harleys are a dime a dozen so I"m not too concerned about screwing anything up.

Maybe you can answer another question. Do you guys keep all questions within the same project thread? As in, yeah, the holes look like ****, i"m going to cut the top and bottom halves of the cover off and need advice on how to finish the edges. That kind of stuff.

If it pertains to the same part, keep the questions in the same thread. If it is another part, but same bike, usually in the same thread. If it is something completely different, usually a new thread

 

[little d]

OK, if you are going to try it yourself, take the button head bolt out of the middle and put in a longer bolt and tie a loop in a piece of string. With the cover off and the air filter still on, hook the loop over the bolt, take a marker and determine where the edge of the filter is.

Now with the cover back on, you can lay out the first radius (past the edge of the filter) and add to that farther out, then you can determine the spacing on how big the holes are.

You can add "speed holes" to the top, front, bottom and rear by laying the cover on a flat surface and blocking a marker up off of that surface to the desired hight (center?), ether moving the marker and blocking or part.

Post pics as you go and we will try to help as much as we can,
D

EDIT; I'm with Kevin, add to this thread, we can see if something new has been posted and are more inclined to look at it as opposed to maybe missing a new thread.

 

[Ed ke6bnl]

I say punch the holes not drill them

 

[srmofo]

If you insist on doing this by hand, I would make a paper template in a CAD program. Draftsight is a free program that will be sufficient for your needs.

Lay the holes out in your desired pattern, then print 2 copies, cut them down to size, and glue stick them to your part. It's the only chance you have at getting a symmetrical finished product. From there you can center mark the holes and then drill or punch to the size you need.

That's a tough job on a flat piece of steel, it's even harder or curved 3d shapes without proper tooling

 

[butsir]

I use masking tape to mark the center of the holes and follow him previously said Kevin; this cover is steel, by making these holes will rust.

maybe this will can be helpful:

http://www.hdforums.com/forum/dyna-...-air-filter-mod-for-more-power-and-style.html



(I hope you understand my english)

 

[1953mercury]

Remember, holes anywhere but on the outer edge will be admitting unfiltered air into your engine. Might seem obvious, but you don't want to end up on the WTF thread. Mike

 

[BoonDockSaint]

I didn't disappear, I got sidelined with siatica. After everyone answered my question, I didn't want ppl to think I just disappeared. As soon as I can stand up straight, I'll get it taped up and drilled and post pictures, good or bad.

 

[little d]

Hope ya get to feelin better soon and yes, I for onw want to see how it turns out,
D

 

[BoonDockSaint]

Well, 2 back surgeries and I'm better than new!? Unfortunately, I can't say the same for my air cleaner. It's a mess.... but here it is, in all it's misaligned glory. Now we know why I'm not a machinist or tool maker.... srmofo, I actually did download that CAD program but couldn't devote enough time to it to actually use it effectively.

 

[manwithtools]

What was Kevin's address again?

Yo really need to have someone with a mill do this if you want symmetry and holes that don't look like a beaver made them.

After all that - don't forget if that cover is chrome plated steel - it's going to rust around every hole.

 

[LXCam]

Damn I'm too late to the party. As for attaining a clean hole in sheet metal, specially if it's chromed. Drill your pilot hole with a 1/8" bit. Then use a double flute step drill to get to the size hole you want. They do a great job of not wobbling like a standard twist drill and you won't end up with a squared hole. You can still clean those holes up, just make sure the piece is secured and keep a steady light hand with the drill.

Also for lay out you might consider getting a couple cheap throw away plastic rulers. Then drill your center hole out. That'll become your datum and allow you to lay out your arc cleanly since it'll conform to the radius of the cleaner. They also make flexible rulers which are great for odd shaped stuff like this when rounding a radius.

 

[Kevin54]

Boondock....is the part still salvageable? If so, send it up my way and I'll bail you out.

 

[Superbec]

ruined.....

had a bike with drilled cover come in last year, ofcourse the holes were AFTER the air filter

 

[4 FN 27]

Damn I'm too late to the party. As for attaining a clean hole in sheet metal, specially if it's chromed. Drill your pilot hole with a 1/8" bit. Then use a double flute step drill to get to the size hole you want. They do a great job of not wobbling like a standard twist drill and you won't end up with a squared hole. You can still clean those holes up, just make sure the piece is secured and keep a steady light hand with the drill.

Also for lay out you might consider getting a couple cheap throw away plastic rulers. Then drill your center hole out. That'll become your datum and allow you to lay out your arc cleanly since it'll conform to the radius of the cleaner. They also make flexible rulers which are great for odd shaped stuff like this when rounding a radius.

I'd second this option...but if it was mine I would make a quick and dirty fixture and throw it on one of our Lasers...but the next best thing to a Laser is a Tin Snips or Step Drill!!!

 

[zkling]

Ah, I've ran across those a few times after someone has tried to do that free hand. Best thing to do in my experience, is to mill out a pocket and install a screen/mesh/expanded of some fashion. It will look much more symmetric and even provide better airflow in the end.

 

[BoonDockSaint]

Thanks all! hehe MWT said "beaver"..... The holes don't look bad under the tape, they're just not where i wanted them. Even if I had succeeded, it would have looked like **** but thanks for offering to bail me out Kevin! NOW, I"m going to "just" cut the center out and make a top hat. The filter element is conical and solid on top so the element will be exposed with the trim on top. First, I have to go start another thread about the vise I bought and am attempting to restore..... Between all the new tools, little projects etc, I don't know if you guys are a blessing or a curse!

 

[Kevin54]

Boon.....before you cut it up or destroy it any worse than it is, I'm certain I can fix it for you. I can oversize the holes somewhat and move the center of the holes so they will be symmetrical off of the center of the cover. It shouldn't take but an hour to fix it. It would only cost you a couple of bucks plus shipping.

 

[Hephaestus29]

If you're punching holes in something like that, I would think it might also dent or cave in
the area some.

If you are going to drill or punch something like that you might consider filling the back side with some kind of epoxy or something for support. I would first use saran wrap or something similar so that it doesn't stick to the part.

 

[kkroger]

Guys try a rotobroach for this sort of thing instead of a twist drill... otherwise leave it to a pro.... Heck I do this sort of thing all the time and I would have taken Kev up on his offer!
Mainly because I don't want to do it!

 

[BD1]

Save yourself more grief and ship to KEVIN.
This reminds me of some local farmers that attempt to do a welded repair , really screw it up, and THEN bring it over to me.
Can you locate a '' insert '' of what you want in the finished product ? Maybe a option.

 

[csp]

No matter who continues with modification that part is going to rust now.

 

[astroracer]

Use a set of Rota-Broaches for perfectly round , clean holes. This could be done offhand with a drillmotor if you go easy and tape the cover up well.
Mark

 

[ryanm]

Boon.....before you cut it up or destroy it any worse than it is, I'm certain I can fix it for you. I can oversize the holes somewhat and move the center of the holes so they will be symmetrical off of the center of the cover. It shouldn't take but an hour to fix it. It would only cost you a couple of bucks plus shipping.

this is an awesome gesture on your part. OP you should feel fortunate to have this offer. just take him up on it!