R8 to Drill chuck

[alan camby]

Title says what i want.

I am kind of a newbie when it comes to milling machines. I have one of the table top Taiwan built milling machines that uses a B size drive belt. The speed settings start at about 130 rpm. My drill press goes down to 250rpm and has the small 3L size belts that like to slip under load.

Anyhow, I want to put some kind of drill style chuck on my mill for using hole saws. Every Hole Saw 1/2" drive mandrel I have seen uses a Hex or triangle drive design so that a drill chuck will grab the flats of the arbor.

From my school of hard knocks I have learned that some, If not all, key less milling drill chucks don't like to grab anything but round tooling. The 3 lobes don't seem like they are designed to grab a hex or three flat drill bit. Well all my drill bits have the 3 flats on sizes 3/16" and larger.

What is a good cheap R8 adapter to drill chuck taper or thread?What are my options on chucks that can drive the hex? Is this my best option for putting a hole saw in a mill? Don't really want to buy annular cutters for the mill. I see all kinds of cheap china r8 adapters to a key less drill chuck on Ebay but don't know if they will grab a hex.

Please don't get to fancy with the terminology as I will get lost quick. Seems to be a bunch of different tapers, collets, collet holders, ect. Right now the only thing I use in the mill are the cheap collets that go up in the R8 taper and are pulled tight by the draw bar.

Thanks,
Alan

 

[alan camby]

These are interesting. Anyone use something like this? Do you think the collet would slip on the round shaft?

http://www.paragonmachineworks.com/cgi-bin/commerce.cgi?search=action&category=HS07

 

[_Dock_]

http://www.msdiscount.com/catalog_list.aspx?cat_id=6050&category_site=STARTOOL

 

[gearbuilder]

Alan,

There is a great used chuck on Ebay now. Item number 230914126391. This is a Jacobs ball bearing chuck.

Jamie

 

[Charles (in GA)]

All you need is a chuck and an arbor for R8 to whatever Jacobs Taper the chuck requires.

Here is a R8 to JT33 arbor

Here is an R8 to JT3 arbor

Here is a R8 to JT2 arbor

Here is a R8 to JT4 arbor

A Jacobs 18N chuck is a 1/4 to 3/4 max ball bearing chuck, it requires a JT4 taper to mount it, thus the arbor just above this would do. There are numerous Jacob 18N chucks on Ebay. I highly suggest not getting one that is already mounted on a different arbor, as you may find it impossible to remove that arbor. I had one like that, and it took the machinist at work to get it separated. They dipped the arbor in liquid nitrogen (keeping the chuck out of the Nitrogen, and the arbor shrunk enough to come loose.

Charles

 

[alan camby]

Cool, Thanks for the help.

Never have understood what the proper machine is for driving a hole saw.

Look at a corded drill. Directions will say something like 5/8" maximum hole size in metal.

Look at a drill press, even a 2 hp unit and it will say max 1-1/2" or so.

So, I guess we just all break the rules
What are you supposed to use to drive a 4" hole saw.

Look at this chart
http://www.fairburyfastener.com/holesaw_speed_chart.htm
85 RPM for a 4" saw. I don't have anything that will go 85rpm.
A geared head drill press will cost you $5k plus. That is the only way I know to get 85rpm.

 

[alan camby]

So, are all of the keyless style drill chucks for round tooling?

 

[lilscorpion]

A bolt. All hole saws are threaded at one end. Obviously they're different depending on size. Anyway, I used to notch hundreds of 1.75" x .250" wall DOM tubing in a session using this method. A bunch of u-bolts I had also had the right thread so I cut them up and used them too.

I found that the shock studs that come in kits I got at one point had the correct thread (maybe 11/16 fine?) I cut the end off of the bolt and chuck the shank in a collet and go. The ones I used for production I welded the hole saw to the stud so I didn't have to mess with it spinning.

I use a cheap R8 collet I purchased specifically for the task and away I go.

If your notching a piece of tubing (just guessing) or anything else where the hole saw will have pressure on one side of it, be careful of how much feed you give it. The offset pressure will blow the saw apart especially the bigger ones that are welded. The saw will tell you when you're pushing too hard. It's much easier to do it manually because you get the feedback. It's when you use the auto feed that you need to pay attention.

 

[lilscorpion]

I forgot to mention that I stopped using the hole saw drill adapters because they seemed to get wrecked quickly and at $20 a pop, I needed a cheaper way to hang on to the saw.

 

[alan camby]

A bolt. All hole saws are threaded at one end. Obviously they're different depending on size. Anyway, I used to notch hundreds of 1.75" x .250" wall DOM tubing in a session using this method. A bunch of u-bolts I had also had the right thread so I cut them up and used them too.

I found that the shock studs that come in kits I got at one point had the correct thread (maybe 11/16 fine?) I cut the end off of the bolt and chuck the shank in a collet and go. The ones I used for production I welded the hole saw to the stud so I didn't have to mess with it spinning.

I use a cheap R8 collet I purchased specifically for the task and away I go.

If your notching a piece of tubing (just guessing) or anything else where the hole saw will have pressure on one side of it, be careful of how much feed you give it. The offset pressure will blow the saw apart especially the bigger ones that are welded. The saw will tell you when you're pushing too hard. It's much easier to do it manually because you get the feedback. It's when you use the auto feed that you need to pay attention.

Thanks, I have a couple of those shock mounts in the garage.

I have stripped out a few hole saws myself. I found the Lenox with the thick base work better then the Morse stamped steel base. The Morse seem to strip easy if you don't use the pin drive in the arbor.

 

[larry_g]

So, are all of the keyless style drill chucks for round tooling?

Alan your scaring me. Drill chucks are for drill bits not tooling. If your think of putting cutters in a drill chuck it is the wrong thing to do. You can put 3 sided bits in a drill chuck. What are you cutting a 4" hole in? There are other ways of achieving a 4" hole.

lg
no neat sig line

 

[alan camby]

Alan your scaring me. Drill chucks are for drill bits not tooling. If your think of putting cutters in a drill chuck it is the wrong thing to do. You can put 3 sided bits in a drill chuck. What are you cutting a 4" hole in? There are other ways of achieving a 4" hole.

lg
no neat sig line

Sorry, said I don't know all the terminology

I am not a huge fan of hole saws. They are just a cheap way to get a large sloppy hole in metal.

Has anyone ever noticed that some of (I don't know maybe all) the keyless chucks don't seem to have 3 fingers that grab in a triangular shape. The fingers are 3 concave bars that seem to form a round pattern.

Warning, I am from Indiana and speek hick

 

[lilscorpion]

Chucks were designed to grip a round drill rod. Drill chucks have three jaws inside that grip the tooling. They should have flat or what appear to be pointed teeth not concave. If they're concave, they're worn if not heavily worn. As for tooling that has three sides machined into them - someone figured they could prevent the slip of tooling by machining the three sides on a rod to help prevent it from slipping or rotating in the jaws of the chuck.

 

[alan camby]

Chucks were designed to grip a round drill rod. Drill chucks have three jaws inside that grip the tooling. They should have flat or what appear to be pointed teeth not concave. If they're concave, they're worn if not heavily worn. As for tooling that has three sides machined into them - someone figured they could prevent the slip of tooling by machining the three sides on a rod to help prevent it from slipping or rotating in the jaws of the chuck.

The chuck that i saw slipping on a hex hole saw arbor was rounded from the factory. I was at work and a guy wanted me to look at the mill with him. He said that the chuck would not grab. After examining the chuck, i told him it was not designed for a hex.

It looked like this.
http://www.ebay.com/itm/ROHM-SUPRA-...1?pt=BI_Tool_Work_Holding&hash=item5646e42a23

I just don't want to buy a keyless chuck and receive something that looks like the one in the link.

 

[neophyte]

The chuck you linked to on Fleabay doesn't have concave jaws. The parts of the chuck you see in the photo that look concave is part of the chuck body. The fingers on the chuck that grip the drill bit are fully retracted in that photo. That Rohm supra chuck should grip a round or hex arbor just fine as long as it's not broken in some way. It should also be able to grip a round shank with triangular flats milled on it just as well as long as it's not over 1/2" in diameter. The design of the body is just different from the chucks made by Jacobs. Replacement parts are probably available as well.

 

[neophyte]

Cool, Thanks for the help.

Never have understood what the proper machine is for driving a hole saw.

Look at a corded drill. Directions will say something like 5/8" maximum hole size in metal.

Look at a drill press, even a 2 hp unit and it will say max 1-1/2" or so.

So, I guess we just all break the rules
What are you supposed to use to drive a 4" hole saw.

Look at this chart
http://www.fairburyfastener.com/holesaw_speed_chart.htm
85 RPM for a 4" saw. I don't have anything that will go 85rpm.
A geared head drill press will cost you $5k plus. That is the only way I know to get 85rpm.

The specs on hole size on drills and drill presses are for when you're drilling using solid drill bits like standard twist drills. Hole saws are larger, but they remove material only at the periphery of the hole and sometimes at the core allowing one to drill a much larger hole with the same amount of horsepower. It is still advisable to use a lower speed though to prevent over heating of the cutter, and for safety reasons.

 

[lametec]

I highly suggest not getting one that is already mounted on a different arbor, as you may find it impossible to remove that arbor.

No to get too far off topic, but you can drill out the center of an Jacobs super chuck to press the arbor out. I did this to a 20N. Once drill out, I put a rod into the chuck, closed the jaws around it (not tight, just enough to guide the rod) and put it upside down in the hydraulic press. Didn't take more than a couple pumps after making contact for it to POP!! (loud) out.

 

[justanengineer]

I try to keep as much mill tooling on straight 1/2 or 3/4 shank arbors as possible so I can just use it in a collet quick and easy. I never really saw a reason to use much of anything R8 taper other than the collets themselves and a few odd items here and there.

 

[alex71]

I have some of those. They work well in a mill. Make sure your setup is rigid, those dont have a pilot drill...

These are interesting. Anyone use something like this? Do you think the collet would slip on the round shaft?

http://www.paragonmachineworks.com/cgi-bin/commerce.cgi?search=action&category=HS07

 

[lilscorpion]

I try to keep as much mill tooling on straight 1/2 or 3/4 shank arbors as possible so I can just use it in a collet quick and easy. I never really saw a reason to use much of anything R8 taper other than the collets themselves and a few odd items here and there.

The value of having tooling on dedicated arbors is if you need speed and repeatability in a setup. Tooling changes with a manual drawbar and straight shanked tooling in universal r8 collets = time consuming and difficult to set zero. For the home shop guy it may not make a huge difference since, more often than not, the projects lean toward one-off. I, on the other hand, ditch all of the straight arbors and dedicate the tooling to a machine. If I had a dozen machines, I'd probably have a different opinion as that way of thinking would get expensive.

 

[justanengineer]

The value of having tooling on dedicated arbors is if you need speed and repeatability in a setup. Tooling changes with a manual drawbar and straight shanked tooling in universal r8 collets = time consuming and difficult to set zero. For the home shop guy it may not make a huge difference since, more often than not, the projects lean toward one-off. I, on the other hand, ditch all of the straight arbors and dedicate the tooling to a machine. If I had a dozen machines, I'd probably have a different opinion as that way of thinking would get expensive.

Certainly, but if I was really interested in speed I wouldnt be using anything with a R8 taper, just as if I was looking for precision. jk.

Seriously tho, it all depends on the individual's needs. If I needed speed, I would have a heavier duty taper (40 or 50), a power drawbar, and dedicated holders along with a much heavier cnc machine. OTOH, I dont need speed so I prefer to baby my lil manual machines and tooling. I keep power drawbars and their advanced wear rates away, and I locate tool height manually in about a minute when I need it - sometimes I dont. I also guarantee the height is correct in the process and avoid trusting the machine as its proven expensive and frustrating in the past.