Mill/Drill Questions

[Michael Peet]

Hi all,

I started out looking for a drill press, but now find myself intrigued by the "mill/drill" machines.

Having read all the threads I could find here, I still have a couple questions I was hoping one of you kind folks might be able to answer.

I see that the dovetailed ways seem to be preferred "for accuracy"; what makes the columnar types inherently less accurate? Are there any benefits to them?

I can use a mortising attachment on this, right? I have read that drill press mortising attachments are so-so; will they work better on a mill/drill? They seem beefier. Or would you use a straight cutting bit and simply cut a slot in one pass?

Grizzly has a lot of mill/drill products. I had no idea. How many of you have one and are happy with it?

Thanks for any input!

Mike

[Rod Sheridan]

Hi, most of the mills I've seen have low spindle speeds, more suited to metal working than wood working.

If you look at slot mortisers, most are in the 5,000RPM range, or even higher.

You could use a metal working mill to make mortices, the X-Y table is good at that sort of work, however the lower spindle speed isn't ideal for it.

Milling machines are made to accept the large horizontal forces required for milling, and a dovetail column is the standard approach to being able to accept that sort of load.

A round column will have problems preventing the head from rotating under those forces. A round column machine would be for very light use.

Note that a drill press column doesn't have any sideways loads imposed on it.

If I was going to spend money in the thousands of dollars range for making mortices, a horizontal slot mortiser would be my choice.

Regards, Rod.

[george wilson]

The mill drills have a cast iron column. I would not want to mortise with one.

The column bends more as you raise the head,causing the head to nod a bit. This keeps the spindle from being perfectly square with the table.

Grizzly offers a milling machine for woodworking. It would be a much better choice. It is a knee type machine,much better than a round column type. I used to have a mill drill in the late 70's.

I agree that a purpose built mortiser would be better. I'm afraid that the high forces required for mortising would break off the cast iron teeth milled directly into the spindle of the milling machine,or drill press. I have seen a good old 20" heavy duty Delta drill press ruined by breaking these teeth off of the spindle. And,it probably was made of better cast iron than you'll get with a new import. Cast iron is inherently NOT a good metal to take these kind of stresses. It is brittle.

[Keith Outten]

I own a Grizzly mill/drill and I wouldn't trade it for any drill press on the market. A larger mill like the Grizzly woodworkers mill would be better though :)

The problem with small mill/drills with round columns isn't that they are weak, when you loosen the two bolts on the head so you can raise or lower it you can lose your center point.

My mill/drill has handled every load I have ever placed on it from very large drill bits, hole saws, lots of milling cutters and routing tasks. A machine that is made for metal working isn't challenged by woodworking jobs.
.

[Danny Burns]

Wood and metal mill drill.

http://grizzlyindustrial.com/products/Wood-Mill-Wood-Metalworking/G9959

Power feed.

http://grizzlyindustrial.com/products/Wood-Mill-Wood-Metalworking-w-Power-Feed/G9977

[Richard Bell CA]

Michael:

I have had a Jet JMD-18 for 18 years now, and agree with virtually all of the comments above. Mine is used more for light metal work and accurate layout of holes in both wood and metal. It is no Bridgeport, but it gets the job done with light cuts. My biggest gripe is the round column, mainly for losing the center point when adjusting the height as Keith mentioned. If I had it to do over again, I would probably look at a different column configuration.

It really depends on what you need to do. I have used mine for making machine parts and tooling, some of which I have posted on this forum. I also set it up to true tenons on bowls. I am still glad I bought it, and consider it as a complement to my woodworking equipment, rather than a replacement.

Richard

[William M Johnson]

I also have owned an used a mill/drill extensivly for wood but mostly metal. They are great if set up properly. The slow speed is not a problem in my opinion. As mentioned earlier the biggest problem is that when you raise or lower the head you have to "recenter" it over your work.

I have made lots of tennons with a "low speed" milling machine and the results are fine.

There is too much backlash in the Z-axis crank for the gradations to be of any use,so you will need to mount a long travel indicator for Z travel.

DO NOT try to mill anything by holding an endmill in a drill chuck. Always use a collet or preferably an end mill holder.

I now have a new Variable Speed Bridgeport (yep a real one) but I thought the Mill/Drill was a great tool for the money.

[Michael Peet]

Thanks for the info guys, very helpful.

[harry strasil]

I have a Bridgeport Vertical Mill and as big and heavy as it is, it was only designed to drill a max 3/8 inch hole with the power down feed.

Makes a good router tho, I used it to cut the 1/2" wide by 3/4" deep dadoes in the sides of Pin Oak timbers for my Nu WWing bench Wagon vise gibs.

http://img.photobucket.com/albums/v81/irnsrgn/nu%20bench/superrouter.jpg

[george wilson]

Actually,I milled al the parts for the 18th.C. fire engine I posted in the Neanderthal section on a mill drill. Some of those castings were very large,and just barely inside the work envelope of the machine. The biggest casting looked like 2 fried eggs stuck together,and was ABOUT 20" X 10". Those are only from memory. Fortunately,the metal was very easy to cut bronze.I was able to use a big flycutter on the mill,else the job would have been too large. The highest precision was not needed on this job,as the parts bolted together with 1/4" thick leather gaskets.

A mill drill was what I had in 1982,and a 10 X 24" Jet bench lathe. I was still Musical Instrument Maker till 1986. Then,I got larger machines to use,and a large shop to use them in.