How can I hold these parts to mill/drill them?

[mhackney]

As some of you may know, I am a reelsmith. I've been making reels by hand for a while and am publishing my first book on the subject (The Reelsmith's Primer - due to be in print early 2010. I've been cncing my mini mill (Micro Mark) so I can automate a lot of the hole drilling and ultimately to be able to do fancier cutouts than just simple holes. Here is a photo of a typical reel plate:



These are 2" to 3" in diameter and start as 0.032" brass or nickel silver sheet. Here is the finished product:



I usually drill the spool plates 2 at a time and have a very primitive jig I made to hold the parts and index them to position the holes. I would like to use my mill to do that along with a rotary table if necessary. Currently, I pre-drill 1/8" pilot holes and then enlarge them with counterbores with a 1/8" pilot. This makes nice round holes in the thin brass sheet material. If you ever tried to drill round holes in sheet brass you know what I mean!

So, the question is, does anyone have any ideas on how to hold these parts on the mill or rotary table to drill the holes? Assume the parts are turned to diameter and have either a 1/4" or #29 hole drilled in their center. It would be great to gang drill 4, 8 or more at a time.

cheers,
Michael

[King bob]

Take 2, 1/4 inch steel rounds and sandwitch 10 or so brass plates between them. Bolt everything together with that 1/4 center hole. The steel rounds will need to have your hole pattern already drilled in them. The rounds should also be larger thanthe brass and shold have 4 equally spaced holes spread out larger than the brass for extra clamping bolts if needed. Then just drill through the existing holes in the steel, hell this is the same kind of jig i would build for doing this manually.

[mhackney]

Thanks, that is along the lines of what I was thinking. Do you think it makes sense that all of the holes in the steel plates be a little oversized - say 5/16" (my largest hole is 1/4") - and I can use the same set to drill both the pilot holes and the enlarged holes?

Cheers,
Michael

[TXFred]

Pocket a piece of aluminum to match the outer diameter of the hole. The depth of the pocket should be a little less than the overall thickness of your stack of metal. So, if you're doing four disks at once, (4 x .032) - .016 = .112 deep.

Drill and tap multiple holes outside the perimiter of the pocket so that your clamping kit's studs will fit.

Use the clamping kit to secure the metal in the hole. Depending on the pattern you'll be milling, you can locate the clamps as needed. With the pocket, you won't need much in the way of clamping force. Just grip the disks in a couple of places around their rims and they'll stay in place so long as you don't take too heavy of a cut.

Now you have a jig that you can mount on your table and use for mass production.

[mhackney]

TXFred, that is interesting. I am not sure that I understand the reason for tapping the perimeter holes. Couldn't the pocket plate have simple holes that the studs pass through with a washer & nut to secure it to the table? As long as the pocket plate was not too much larger than the disks, the clamping kit (or a plate like king_bob mentioned) could secure the stack.

What I like about this idea is it centers the disks based on their outside diameter (which I can precisely turn on the lathe) and not the central hole. So far, using a 1/4" bolt for aligning the disks on their central hole has too much slop. At the very least I will need to turn a higher precision shaft to slip the disks on. This idea would not require that though.

cheers,
Michael

[TXFred]

TXFred, that is interesting. I am not sure that I understand the reason for tapping the perimeter holes. Couldn't the pocket plate have simple holes that the studs pass through with a washer & nut to secure it to the table?

Yes, you could do that and secure it to the table's t-slots. You may want to do that just to secure the jig to the table.

I mentioned tapped holes because it gives you more flexibility in how you clamp the work onto the jig. As you play with the designs of your reels, you may need that flexibility. The X2's table doesn't give many options for clamping. Turning your jig into a fixture plate gives you more options.

[TurdCurd]

I'd take a block of 4x4x1.5 Alu, square it up in the mill. Mill a pocket 1" deep x 2" diameter. Mill a second pocket on top of the 1st 3/4" deep by 3" diameter. Then find the center of the pocket and drill and tap for a 10-32 screw. Go on the lathe and turn up a few .250x2.0" diameter Alu plates, or just buy 2" diameter stock and face to size. Do the same for 3" Diameter. While still on the lathe, drill a 1/4" hole in the middle. These will be sacrificial plates to prevent blow out in the bottom while drilling the holes. Then turn up One (1) .250x2.0 diameter and one (1) .250x3.0" diameter steel plates. While the steel plates are still in the lathe, drill a #8 hole thru the center of them. On the lathe again, turn up a piece 3" diameter outside, 2" diameter inside, 3/4" width. This will be a sleeve to change the jig from a 3" diameter jig to a 2" diameter one. In the two steel plates, drill your hole pattern with a drill that is the next size up from the size that you need the finished size to be.

To use: Machine your blank pieces to size and drill your 1/4" hole in the middle. For 3" diameter pieces, drop a 3" sacrificial piece in the bottom, Pile in your pieces, put on the 3" top (pattern) plate, and secure it thru the middle with a 10-32 screw. Being the 10-32 screw is smaller than the 1/4" hole, the pieces will be aligned by the outside diameter. Drill your first hole, making sure to go into the sacrificial plate but not your jig. after the 1st hole, drop a pin in the hole to keep the plates from moving/spinning/shifting while drilling the other holes. For 2" diameter pieces, use the sleeve with the 2" diameter top (pattern) plate. With the top (pattern) plates being the same diameter as the jig pocket, you don't have to fill up the jig in order to secure the plates for drilling.

[MattTheNoob]

I'm with King Bob et al, only I'd go with drill bushings like used in a jig bore machine. For drilling thin plate, you may want to experiment with modified drill bits. A "flat" drill or something similar might give you better results with the bushings.

If not, your jig can accept a bushing for the pilot drill, then a bushing for your counterbore.

Personally, I'd x-y around to the hole locations rather than get a rotary involved, but that's just me... I don't know how to make fancy reels. Heck, I can't even catch fish.

[pete from TN]

I am assuming that is some sort of fly fishing reel no? Got any specifics of the mechanism inside? I live in East Tennessee and there is a lot of fly fishing streams locally. Have thought of buying a reel but it would be really nice to go using my own homemade reel.... nice work!! peace

[mhackney]

Pete, I have written a book on making fly fishing reels and waiting for it to come off the printer. My publisher is Whitefish Press. Meanwhile, check out my reelsmithing forum at www.reeelsmithing.com/forum

cheers,
Michael

[pete from TN]

Linky no worky ...... Oh wait a minute, I think there might be too many eeees!! peace

[BobWarfield]

A real simple CNC punch could do that work so fast.

Search this page:

http://www.cnccookbook.com/CCBlogSep2008.htm

for "CNC Punch Press" to see a cute little CNC conversion on a benchtop punch press. Get a little motorized press of eBay and you could really fly.

Cheers,

BW