Newbie With "New" Old Mill Drill

[SusanX]

Hi folks,
I have a 1 car garage packed with woodworking equipment. Recently, I developed an interest in metal working. I bought a vintage little 1938 metal lathe and a mig flux welder. I wanted to buy a milling machine, but resisted due to lack of funds and space.

Then, on good ole Craigslist, one night, I saw an ad that had been up for 3 hours. It was for an excellent condition 1976 Jet-16 benchtop milling machine. The price was $300. This price is unheard of in the San Francisco area. Used Sieg tiny mills go for $600 used in craigslist. Anyways, when I googled the specs on this model, I read that this machine weighed 650 lbs. I felt this was my only opportunity to own a non-toy milling machine. The price was so good and the machine was so heavy that I overlooked the fact that the mill had the dreaded round column. But, hey, I am a newbie, not a career machinist, so I sent the seller an email expressing interest.

I expected to not hear back from the seller since I responded hours after the post was put up. Then, 2 days later, the seller responded. When I went to the address where the mill was at, I learned that the owner passed away recently. He had a neck injury 10 years earlier and the mill sat untouched since then. The seller had the original manual. In the manual, it stated that the mill came with an MT3 spindle. However, when I later went through all the accessories that came with the mill (tons, including 3 vises), I began to suspect maybe an r8 is in the mill instead of mt3. After a long time, I was finally able to remove the chuck

Here are my newbie questions (finally!):
In the pic, does it look like my mill is mt3 or r8?
Does the bottom portion of the drill chuck that I pulled out of the machine separate from the shaft that is shown in the pic? If so, how can I separate it without damaging the poor thing any further (I scratched the metal trying to get it out of the mill)?


Thank you. Your friendly, experienced feedback is greatly appreciated

[SteveHGraham]

I don't know how you got the chuck and adaptor (R8) out of the mill, but it shouldn't have been hard. You loosen the drawbar and then whack the top nut of the bar with a hard object to break the spindle's hold on the adaptor. After that, the adaptor should be loose, and you should be able to turn the drawbar with your fingers to get the adaptor to drop.

That adaptor is almost certainly not part of the chuck. It's held on by a taper. Whoever installed it put the chuck on the taper and then pressed the taper into it using the mill's spindle or some other means.

There really is no reason to separate the chuck and adaptor, unless you want to replace one or the other.

The customary way to get chucks off of tapers is to use wedges. Jacobs makes them. Personally, I have found that they don't work well, because the steel is so soft the wedges break. Anyway, you put one wedge on each side of the chuck, and you press them toward each other. As they go in, they pop the chuck out.

Another way is to drill a hole in the bottom of the chuck. This exposes the end of the taper. You can then insert a punch and press the taper out of the chuck. Some Asian chucks already have a hole for this purpose.

Final suggestion: breaking posts into small paragraphs will make people more likely to read and respond. Good luck.

[SusanX]

Hi Steve,
I followed the textbook method of removing a chuck, but the chuck was super stuck, despute using a mallet and hammer on the drawbar and unscrewing it off. I had to pry it off. I didn't want to do it that way, but following the rules wasn't working. I will follow you advise and edit my post to be easier for readers. So, just to confirm, are you saying despite what the manual says, the mill has a r8 spindle and that what is attached to the chuck is an adapter to go from r8 to mt3?
Susan

[SteveHGraham]

RE the taper, I'm just going by appearance. An MT3 taper is long and very gradual, while an R8 is short and has a pretty abrupt angle.

Here is a link to an Amazon MT3 end mill holder. You can see what I mean. I'm sure someone else here has a mill like yours and can give you better answers. Saturday afternoons are slow!

https://www.amazon.com/HHIP-Morse-Taper ... B01N54LTNT

If you had an MT3 taper, it could be a convenience, because if you got an MT3 lathe later, you could use some of the same stuff with both tools.

Prying things out of a mill spindle is probably a very bad idea. If you bent the spindle, you're going to have to replace it, because it will have a tremendous amount of runout.

To help you in the future, the harder the material you hit the drawbar nut with, the more likely it is to knock the drawbar free. You need a very sharp impact. It doesn't have to be a heavy impact. Just sharp. I use an aluminum tool I made myself. Some people use brass. You could beat one all day with a rubber hammer and never get it off. The nut should be hardened, so you shouldn't have to worry about damaging it.

I don't want to insult your intelligence, but I will say this anyway: you have to loosen the drawbar nut before you bang on the nut to loosen the taper.

[SusanX]

I did loosen it. Anyways, thx for your comments, Steve

[SteveHGraham]

I'm glad to know I underestimated you. Hope everything works out.

[Glenn Brooks]

Hi, second what others have said. The Collet you show in the picture has the shape of an R8 taper. An MT 3 will be one continuous taper from top to bottom -end to end to end. So,, you will need to measure the taper in the spindle and/or inspect more closely to resolve the apparent discreapancy. Maybe jet changed their design and didn't print a new manual, or someone reground the spindle to accept R8. No telling...

In answer to your question about chucks- there a few chucks around that are actually attached to the Collet -they don't separate as they are all one piece! Maybe you have one of these rare birds! Squirt some penetrating oil around the base and watch closely to see if any draws down inside the Collet face. If so, it's just stuck with old age. If not- well, it won't ever separate..

BTW, I have a couple of tapered collets that are a bear to remove tooling from. On one machine, I use a very large cold chisel - on edge, inserted between the tooling and the shoulder of the Collet. (Not the sharp end ( Nervous laugh)! Use the slanted side surfaces as a wedge. Then give the chisel a big wack with a nice large machinist hammer. Tooling pops right out.

Sometimes drill chucks are harder to remove because they are seated deeper in the taper and subject to decades of compression when drilling holes, over and over and over.

Last resort, just buy a shinney new Collet for 8 or 10 bucks and invest in a quality chuck. Keep the old one around to look at now and again.

I have a similar size Grizzly round column mill, albeit a bit larger in the table and base. Nothing wrong with these mills. They just don't take big depths like the old industrial bemouths. mine is happy with .030 depth of cut and shaving off half the diameter of the end mill or less. Sounds like for your use and small shop, yours will work just fine

Let us know what you find out, as you progress through your inspection.

Glenn

[John Evans]

That is a R-8 style collet ,you really don't want a spindle with a Morse taper ! Tooling hard to find and sometimes really hard to remove from the spindle. The chuck end of your collet has what is called a "Jacobs" taper and is hard to remove from a chuck intentionally. Chuck or collet is many times marked as to what Jacobs taper it is. All tapers tend to be hard to remove after a period of time ,R-8 is usually the easiest.

[GlennW]

intentionally

Isn't that the truth!

[SteveHGraham]

I froze an R8 arbor and put a heated Albrecht chuck on it, and I thought it would be on there forever. One day it fell off for no clear reason at all. But God help you when you WANT one to come off.

[John Evans]

I froze an R8 arbor and put a heated Albrecht chuck on it, and I thought it would be on there forever. One day it fell off for no clear reason at all. But God help you when you WANT one to come off.

Clean and dry you should need to do neither ! Were you side loading the chuck when it came loose??? Tapers without draw bars should never have side loads applied !!

[stevec]

That is a R-8 style collet ,you really don't want a spindle with a Morse taper ! Tooling hard to find and sometimes really hard to remove from the spindle. The chuck end of your collet has what is called a "Jacobs" taper and is hard to remove from a chuck intentionally. Chuck or collet is many times marked as to what Jacobs taper it is. All tapers tend to be hard to remove after a period of time ,R-8 is usually the easiest.

John, I don't believe that is a "collet" I would call it an "R-8 arbor.
Correct terminology is important, especially when trying to help/advise a newbie.