Author Topic: Cross Drilling Rotors (Read 37577 times)

754 · « **Reply #50 on:** December 19, 2007, 10:19:10 PM »

Most small drill presses dont go slow enough to make the job easier. I did my first discs on a small drill press.

I found a cool trick when I did my first ones in the 70,s. I found some circular graph paper, laid it out then taped it to the disc and punched holes through to lay out the pattern. I had trouble getting the paper sometimes, found out later it is called polar graph paper I do believe.

A really cool trick I figured out back then for countersinking, as drill presses usually turn too fast. I took a carpenters bit & brace with a twist drill chuck on it and held the countersink with that. Lay the disc on a couple 2 x 4's, give ot light pressore and 1, 2, 3 turns and done.. go to next hole!!.

Another trick to get the rows dead nuts.. machine a spacer to fit center disc bore - about .005. Tap center, Bolt this to the table from underneath or to a slot. Then take a bit bigger spacer that grabs the inner portion of the disc carrier.. about 1/4 to 1/2 bigger than the first spacer, drill a through hole mount on the same stud holding the center plug. Now when you loosen a nut on top of the bigger washer it allows the disc to turn to index to your marks, tighten nut to clamp .

Then loosen the table to swing over and lock for the other rows, only move table once per row, and holes will spin in perfect circle with out runout!

Simple.. right!!

Terry in Australia · « **Reply #51 on:** December 19, 2007, 11:31:06 PM »

I invested in a cheap Chinese "rotary table" for my mill/drill, and machined up a disc mounting flange on my lathe, and it works well.

Use a slow speed, cobalt drill and straight dishwashing detergent for lube, (no oil!) and it'll cut through like a knife through hot butter. Here's a pic. Cheers, Terry.

cb650 · « **Reply #52 on:** December 20, 2007, 05:56:44 AM »

I musta did something wrong when I did mine. I used a regular HHS bit. Layed it all out center punched drilled first with a 1/4" then went back with 5/16" and a few went to 3/8" then a light champher. On a drill press running slow and cutting oil. Took about a hr a disk. Thought I took picks but havent run across them yet.

Terry

Terry in Australia · « **Reply #53 on:** December 20, 2007, 04:09:09 PM »

That's the benefit of the method I used, no centre-punching, no little/bigger/big drill bits, just turn the handle and punch a 10mm hole every 20 degrees. One hour per disc? I've got a very low attention span! Cheers, Terry.

SEBNN · « **Reply #54 on:** December 29, 2007, 08:00:19 PM »

Quote from: cafehonda on November 03, 2006, 03:12:42 PM

Another thing to consider is that if the holes you drill are too large, you begin to lose braking power because of insufficient surface area. The brake pads can't get much grip on a hole, see. I've seen guys with giant 5/8" holes in their disks, looking like swiss cheese. In my humble opinion, and I think the opinion of most manufacturers, 3/16" - 5/16" holes are optimum.

Not to be too picky, but surface area doesn't have squat to do with friction. Friction is all about applied force and the coefficient of friction. Though large holes (small braking area) will cause your rotors to heat up a lot faster with less area to get rid of the heat leading to brake fade from smoked pads. And eventually this will toast your rotor as well. Better to go with smaller holes to allow water and other things to clear out while maintaining the most heat dissipating area as possible. Also, drilled rotors look cooler than stock ones. Just my .02.

UnCrash · « **Reply #55 on:** November 23, 2008, 08:28:17 PM »

I recently purchased a Drill Press from Craigs List here in Maine. http://forums.sohc4.net/index.php?topic=43119.0

This unit had a circular table which rotated evenly. I thought I would use this to my advantage for drilling my rotors.

I went to my local mega hardware store Lowes and found a couple great parts in the plumbing and hardware departments that made the process much easier and more accurate.

In the plumbing department I picked up a 2" to 1" Copper reducer and a 1" threaded 4" galvanized rod. In the hardware department I found a 7" bolt, nut and washers to hook this to the table...

Here's a close-up of the setup.

I used liberal amounts of electrical tape to get everything to snug up. I ended up with an easily detachable centering unit for SOCH rotors. There's less than 1/2 mm of play from one side of the rotor to the other.

This setup allowed me to rotate the rotor in place and insure that for each hole I was the proper distance from center.

ev0lve · « **Reply #56 on:** November 23, 2008, 08:46:20 PM »

Man that looks great! Your making me sad re: my own misadventures

What did you use for lube and does your press have adjustable speed?

Iggy

UnCrash · « **Reply #57 on:** November 23, 2008, 09:02:35 PM »

Quote

What did you use for lube and does your press have adjustable speed?

I used some cutting fluid from Sears that has been hanging around in the shop. When it's used up I'll fill up the bottle with un-diluted dish soap which I've used with success before.

I used cobald drill bits. The 1/4 and 5/16 bits had a stepped cutting face. They're the bomb and cut through the rotor efficiently. I was sure to keep the bit cool with drops of cutting oil.

The drill press has 5 speed settings you achieve by moving the belt on top to different pullies. I used the lowes speed setting of 600 rpm.

Viktor.J · « **Reply #58 on:** December 19, 2012, 09:18:52 AM »

Ive also drilled my rotors. At first my plan was to do it in the CNC. I made a "adapter" wich I bolted the disc to and then put it in the CNC fastener. But it turned out that the "aluminium centre" of the rotor was to weak and made the disc to flexible. So I only used it to pre-drill the pattern and then drill them in a vertical drill. I didn't have the best drills, only HSS. So I had to take it carefully and Used plenty of cooling fluid to prevent and heat damage. I drilled 100 holes in about 4 hours. Minus the CNC time

Rotor in the CNC

The first hour of drilling

Done !

Terry in Australia · « **Reply #59 on:** December 20, 2012, 04:09:54 AM »

Nice job mate, and I like that pattern too! Cheers, Terry.

BLUE71TURBO · « **Reply #60 on:** December 21, 2012, 09:19:18 PM »

Quote from: Terry in Australia on December 19, 2007, 11:31:06 PM

I invested in a cheap Chinese "rotary table" for my mill/drill, and machined up a disc mounting flange on my lathe, and it works well.

Use a slow speed, cobalt drill and straight dishwashing detergent for lube, (no oil!) and it'll cut through like a knife through hot butter. Here's a pic. Cheers, Terry.

That's exactly how i did mine. I used my friends mill with a rotory table. I was amazed on how much the time flew by drilling and deburring all the holes on both sides.

But it was worth it.

Terry in Australia · « **Reply #61 on:** December 22, 2012, 01:38:11 AM »

Good job Jon!

Cqyqte · « **Reply #62 on:** December 22, 2012, 07:28:56 AM »

I went at this disc drilling in a different manner. I was cutting some special parts using a friend and his CAD laser table and decided to make a template that would slip over the CB disc and then rotate the template using an index pin to position each vent row.

The template cost me $25 and fits most CB450 and CB750's. The template was drawn up using AutoCAD so using the indexing pin the pattern translates perfectly on to the disc.

Here's a finished view...

I'd offer to lend the template out for the cost of shipping, but being in Canada that cost may be prohibiting

Retro Rocket · « **Reply #63 on:** December 22, 2012, 03:00:12 PM »

Nice....

SF · « **Reply #64 on:** December 22, 2012, 04:01:47 PM »

nice job, is the last hole in each row smaller than the rest?

Terry in Australia · « **Reply #65 on:** December 22, 2012, 04:49:49 PM »

Quote from: Cqyqte on December 22, 2012, 07:28:56 AM

I went at this disc drilling in a different manner. I was cutting some special parts using a friend and his CAD laser table and decided to make a template that would slip over the CB disc and then rotate the template using an index pin to position each vent row.

The template cost me $25 and fits most CB450 and CB750's. The template was drawn up using AutoCAD so using the indexing pin the pattern translates perfectly on to the disc.

Here's a finished view...

I'd offer to lend the template out for the cost of shipping, but being in Canada that cost may be prohibiting

That looks fantastic mate, I reckon you could sell those and make some bux! Cheers, Terry.

Cqyqte · « **Reply #66 on:** December 23, 2012, 04:38:31 AM »

Quote from: SF on December 22, 2012, 04:01:47 PM

nice job, is the last hole in each row smaller than the rest?

Yes I decided to only drill the last hole out to .25" instead of .313" iust incase it was too close to the edge. Good eye !!!

SF · « **Reply #67 on:** December 23, 2012, 08:39:40 PM »

i like that design best, I'm sending a set to gord bush to drill and deglaze

racinchase · « **Reply #68 on:** December 24, 2012, 03:32:24 PM »

Looks great!

ncstatecamp · « **Reply #69 on:** January 22, 2013, 06:32:23 PM »

So i tried this on using a Mill, DRO, (SO. MUCH. EASIER!), a rhino file with measurements, all was going well with my first 4 holes then nothing would drill anymore... lots o smoke, bad noises catching bit, the stainless got a bit to hard it seems. The one thing that would cut it was my centering bit so I had to continue with that. I now have 48 center tapped beveled holes in a cool pattern that are not all the way through my rotor. What can I do to finish these holes all the way through? I no longer have access to the mill but i do have a drill press. so experts what you got?

70CB750 · « **Reply #70 on:** January 23, 2013, 04:52:00 AM »

I drilled my two rotors using cobalt bits from Lowe's, resharpened every 40 holes or so just to keep it going.

SF · « **Reply #71 on:** January 23, 2013, 06:32:32 AM »

how much are the cobalt bits?

70CB750 · « **Reply #72 on:** January 23, 2013, 07:01:14 AM »

Depends on size:

http://www.lowes.com/pd_71202-70-DW1214++G_4294707816__?productId=3382648&Ntt=drill+bits

http://www.lowes.com/pd_71208-70-DW1232++G_4294707816__?productId=3382658&Ntt=drill+bits&pl=1&currentURL=%3FNtt%3Ddrill%2Bbits&facetInfo=

timbo750 · « **Reply #73 on:** June 12, 2014, 04:11:39 PM »

I was doing some research on this topic and stumbled on some printable patterns on the XS650 forum. Well it turns that the disc size is the same which is very convenient so I thought I would put them up here to share.

Each pattern is only a quarter so you print 4 a tape them together, print one first and check the scale as not all printers will print at a true 1:1. The idea is that once you have printed them and placed over the disc you can use a centre punch to mark the holes which is great for those of us who do not have index wheels.

Ewan 500K1 · « **Reply #74 on:** June 12, 2014, 10:01:02 PM »

1. steel rule, compass & protractor to make paper template
2. template taped to disc
3. center puch thrugh template to mark hole positions on disc
4. cheap as you like drill press and cobalt drill bit (one bit did two discs)
5. using cutting fluid
6. make nice swarf

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Author Topic: Cross Drilling Rotors (Read 37577 times)