Dividing head Chuck “through-bore” size

[MikeSull164]

Hi.

May be a stupid question, but I am wondering if it is possible to get a dividing head for a mill that will take a 40mm OD tube “through the Chuck”? To machine 5mm holes at 120degrees at one end of the tube. The tubes are 1200mm in length.
I currently use a slip on tool with pre-drilled holes to drill the holes with a drill but would prefer I could have a set up for the milling machine.

Again, maybe this isn’t possible!

Cheers ,
Mike

 

[romie24]

I my self have a K type K&T dividing head that has a 2 and a 16th bore through the dividing head. They are out there.

 

[Limy Sami]

http://www.rotagriponline.com/index.php?page=shop.product_details&flypage=shop.flypage&product_id=7797&category_id=135&option=com_virtuemart&Itemid=29

http://www.rotagriponline.com/index.php?page=shop.product_details&flypage=shop.flypage&product_id=7798&category_id=135&option=com_virtuemart&Itemid=29

 

[L Vanice]

As Limy suggested, you should be looking for an indexer rather than a dividing head if all you want is 120 degree intervals.

If you want a cheap fixture, make a steel hex block with a 40 mm bore and a setscrew to hold the tube. Hold the hex in your mill vice and set up a stop to locate the end of the tube. Drill one hole, loosen the vice and rotate the hex 120 degrees, tighten the vice and drill the next hole, etc.

Larry

 

[romie24]

Maybe I misunderstood, are you saying you want to drill holes at 120 degrees at that angle? Or 120 degrees apart? I hope my question makes sense.

 

[gtermini]

A hartford chuck would be what I'd look for. Much quicker indexing than dividing head.

Here is a similar job I ran a decent volume of. It was 4 holes, but same principle. It wasn't hard to hold position from the end ±.005 with the swinging stop mounted on a stripper bolt. Vise fixture is just two shaft collars welded on some 1/2 barstock made-up jaw plates. The hartford chuck was just floating around on the table and really only used for indexing. The vise held the work completely.

 

[cyanidekid]

just get a 1.5" high quality hex nut , bore it out to 40mm, drill and tap for setscrews, set tube up in V blocks. nut indexes it.

 

[Garwood]

120 degree hole spacing- chuck on the end you're gonna drill and drill between the jaws.

 

[ratbldr427]

With a 3 jaw just clamp it on the end with the bar resting in v-blocks or vice and make a parallel block out of scrap that sits on the table whose length allows the chuck jaws to sit flat (parallel) to the table, then just rotate the chuck and slip the block between the jaw and table then clamp with a standard strap clamp. You already have what you need.

 

[metalmagpie]

My Rutland 8" indexing super spacer's chuck will accommodate 40mm. Old skool tooling like that is cheap now. You just have to find it.