Milling machine table size

[Dreamcaster]

Hi
[FONT=Verdana, Arial, Helvetica, serif]I am looking at the Grizzly tools G0704 The specs below are what I am concerned about What is the maximum size piece of 1/2" aluminum plate that I could work on? I would be putting 1/4 20 holes on one inch centers would I be able to do a 12" X 24 plate? What is the maximum size I could get away with ? I am thinking it would be double the specs since you can turn the piece around and do the other half but not sure. I am a newbie [/FONT]
[FONT=Verdana, Arial, Helvetica, serif][/FONT]

Thanks
Michael


http://www.grizzly.com/products/Drill-Mill-with-Stand/G0704
Table travel (longitudinal): 18-7/8"
Table travel (cross): 6-7/8"
Table size: 7-1/8" x 26-5/8"

 

[Tom Griffin]

You would need a Bridgeport size knee mill with a 48" table to handle a plate that size in one set-up, and that would be just drilling the holes. It would take a larger mill yet to be able to mill the edges in one set-up. You could get by with a smaller mill, but it would take multiple set-ups to accomplish. You may be able to do it in the mill you pointed out, but it would take four set-ups with two of them inverted. If you plan on doing work that size often, you had better plan on a larger mill.

Tom

 

[Dreamcaster]

Thanks Guys

I almost had a Bridgeport for $1000.00 power feed XYZ DRO Some pickers got to it an the rest of the stuff ( I bet they made a fortune) It was 3 hours away and I was trying to get the logistics together but it sadly it slipped through my fingers. I will keep looking locally.

 

[Mid Day Machining]

You can do a 12 X 24 part on your little machine, but you're going to have to move it 3 times. I would put a hole as near center as you can and then use that hole as you X and Y zero to put in the rest of the holes. Just don't tap your center hole until your part is finished so you have a nice smooth hole to indicate when you move your part.

 

[Tony Wells]

We do not know the requirements of the OP's project. If it is a simple clamping plate, then there is likely no need to attempt to hold a +/- 0.001 position accuracy. An argument could be made considering the PD tolerance of 1/4-20 UNC-2B threads. Hardly could 0.001 error in position affect function.

It's just a guess, of course, but if it a clamping plate, then it could be as simple as an ordinary layout job and a drill press.....or a mill used as such, with the plate allowed to "float" rather than be mounted firmly to the table. In fact, I can virtually guarantee that I would do that plate with that method even though I have a mill with plenty of travel to do it all in one setup. And I full expect I would hit 0.002 true position accuracy. But again, we don't have the entire picture from the OP.

 

[Dreamcaster]

Hi guys
Again thanks for the input we use what is called an optical breadboard for setting up laser projection systems here is a link to what one looks like http://www.thorlabs.com/NewGroupPage9.cfm?ObjectGroup_ID=159 I think this will be a better way of seeing what I am trying to do keep in mind I do not need the specs listed that is Laser research grade stuff that thor labs sells, and we are not needing those tolerances 12X24 is about the minimum size that's useful for our purpose. I was considering making them for my Laser show buddies at a lower cost if you have any interest in looking around the blog where these folks hang out it is www.photonlexicon.com

My biggest battle with Brigeport versus the Grizzly Bear LOL Is space and logistics I am not sure if I want to continue in my garage or move down the basement which would be better for the winter months. The bridgeport, Tool master or any other Knee mill will never get down there, impossible! but the Grizzly G0704 would make it. I would have to keep the Knee mill in the garage no choice on that. Currently I own a Unimat and have made a lot of cool optic mounts with it but I also see the limitations of its size and rigidity so I have to get something that can handle larger projects.

Best
Michael

Hi,

Yes you can locate to +/-.001" with a drill press and with less chance of error than a mill. You just need to use a drill jig. The hardened drill bushings will guide the drill very accurately. Extremely repeatable and easy. This is how the "old timers" did it before CNC and DRO's. It's still a very fast and easy way to accurately places holes on awkwardly shaped parts even at awkward angles. Downside is that due to cost, it isn't really suitable to onesy/twosy parts.

For another fast and also pretty darned good method of accurately locating holes, a marking jig can be made to transfer punch hole locations very quickly and pretty accurately as well. Drill bushings are not needed here. Simple drilled holes do. Though it does take more care to pick up the punch marks. Still if done carefully, a good drill operator can still to +/-.005" without a lot of extra sweat and effort. And again, the repeatability can be pretty darned good.

I honestly don't know the OP's required accuracy level, what he intends it to be used for, how many he needs, and how often he needs to make them. All these things factor into the methodology you choose. But just from my manufacturing experiences over the years, threaded holes seldom need to be more accurately located than +/-.005" on produced parts.

dalee

 

[Dreamcaster]

Thank you Froneck for the auction tip I will be keeping an eye on that. Seems like a good way to go.

In response to the rigger comment yeah I would rather not get into that if possible they are very expensive I got a quote from the company in Morrisville PA right over the river from me, when I was trying to get the Bridgeport from Long Island that made me fall over him my Chair I checked a few other ones and they were all the same price seems like the fix the prices. It would have cost me more than I was paying for the machine itself.

Movers will not do it big tow companies with large flat bed trucks will not do it, you are pretty much on your own to figure out how to get the big top heavy thing home or pay a kings ransom to the riggers. So I would want to know up front if riggers are required before I bid.

Best
Michael

Here is how one guy did it

http://www.truetex.com/movebpt.htm

 

[ScrapMetal]

Here is how one guy did it

http://www.truetex.com/movebpt.htm

That is pretty much how I got my Wells-Index home. I had to drive from Nebraska to Michigan to get it (still cheaper than having it shipped). If possible though, I would recommend renting a "drop-deck" trailer for ease of loading/unloading. The side rails on the drop-deck would also give you a lot more options for tie-downs.



This is where the "drop-deck" really would have come in handy.

-Ron

 

[ScrapMetal]

Thanks Frank, I'm quite proud of my new toy. The biggest trouble with it so far is explaining to the wife just why, after spending bunches of money to get it and get it "working", I need to spend another bunch of money to actually put it to use (buy tooling and such). :biggrin: The best I could do was to compare it to buying a new oven but still needing to buy pots and pans in order to use it.

As for getting something down in the basement, I don't remember where I saw it posted, but in order to get all his machines down in the basement this person cut a huge hole in the kitchen floor and used a crane to lower the machines into place. :thumbzup: Just try talking YOUR wife into that! :worship:

-Ron

 

[Dreamcaster]

Hi Frank
That would be great I think it may be around November sometime before I am able to put out the cash for a big Mill I cant wait to own one but I am in the dog house at the moment with the wife for all of the tooling I have recently purchased. Some of it is HF and grizzly bear (I know its Grizzly tool but I like calling them that) but I do not know how I would ever have afforded it other wise I just picked up a 3" rotary table for $37 dollars on clearance it just makes it on my little unimat. it has one spot in the rotation that I feel a little drag probably a not so perfect bearing but it has already proved it worth on a project I recently worked on.

I think the plan right now will be to clean out the garage and power wash the floor one of my weed killers or insecticides leaked and something does not smell good when I am working in there. Nasty chemical smell. Then I will Resin the floor with self leveling resin in the area the Mill will go. Run 220 from the power box in the basement and get it ready for a phase o matic with a bullswitch. So when I get the new arrival I will be ready to pallet jack it in, hook it up, and not have to scramble.

Its funny the only thing my wife did not have a problem with was purchasing a gerstner knock off tool chest she likes that.

Michael

Hi Dreamcaster
Anything is possible if there is the desire! I had a Sliding gap Leblond and 2 Toolmasters in my basement and no way to get them down there. So I did a Johnny Cash! One piece at a time!!
I do have a large truck, small for me as I'm looking for a larger one. If we both get something at one of those Accelerated auctions I might be able to get it to you. I hauled my 24" Hendey lathe back from Long Island!

Frank