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View Full Version : Used my new mill for the first time today---



brian Rupnow
06-26-2008, 08:45 PM
And a scary time it was!!! First thing I had to figure out was how in heck do I hold down the toolmakers vice I bought. After a bit of head scratching, I cobbled up some T-slot bolts and what I think are called "Picardi" clamps to hold down one end. Then I had 2 long T-bolts but no more clamps, so I made a bridge from a peice of 2" channel and spanned it over the other end of the vice.---this seemed to secure things adequately. My goal was to reduce a peice of brass that was 1" square to a peice of brass that was 23 mm x 16 mm. I have 3 flycutters that I purchased in my tool buying frenzy of 2 weeks ago, but never having used them before, I opted to use a spiral fluted 1" diameter end mill. I am familiar with it, because I had tried a few bouts of milling in my lathe. The first hurdle was "How do I set my height???---Not having anyone close at hand to ask, I lowered the head of the machine on the column untill the end of the end mill just touched the top of the brass peice, then locked it on the column. Then I moved the peice to one side by moving the table horizontally untill I had lots of clearance under the cutting tool. I then used the spindle advance to advance the spindle 2 mm downward and locked it in place (the spindle does have a digital read out). For some reason, the digital speed indicator didn't want to work (I will call Busy Bee about that tomorrow), so I cranked up the RPM's untill it felt right. Using the movement of the table I kept passing the peice of brass under the cutter, and succeeded in making a whole bunch of chips----and I do mean a whole bunch---Jeez what a messy process!!! Everything went fine, and I did accomplish what I set out to do, but I can see a real steep learning curve ahead of me.---Brian
http://i307.photobucket.com/albums/nn294/BrianRupnow/firstmillingjob001.jpg

jimmstruk
06-26-2008, 09:03 PM
Good for you!! You have made first chips, now make some more. Good luck. JIM

lazlo
06-26-2008, 09:08 PM
Congrats Brian, but that mill setup doesn't look safe with the tail clamped with a piece of aluminum channel like that -- the vise will be subject to spin...

You've got strap clamps up front. Another set in back would be a lot more rigid than the aluminum channel.

brian Rupnow
06-26-2008, 09:19 PM
Lazlo---Thats a steel channel with grey paint on it. As my uncle the farmer used to say---"thats strong enough to bull a cow on, if ya could get the cow to stand"---

tattoomike68
06-26-2008, 09:35 PM
that set up is overkill. The vice is a bit overkill, its as big as the whole table.

You might find/trade/build a real mill vice thats more the right size for that machine.

lazlo
06-26-2008, 11:04 PM
Lazlo---Thats a steel channel with grey paint on it.

The material doesn't matter much Brian -- maybe I'm seeing the picture wrong, but it looks like the tail end of the vise is held in place by friction, which means that it can spin around between the gap between the two studs.

If you had used strap clamps in the back, like you did up front, the vise couldn't slide around.

S_J_H
06-27-2008, 08:12 AM
A 1" endmill is awfully large for that small mill. I think you'll have much better results if you stick to endmills of 1/2" max OD. Then use the flycutter for finishing if you need a nice even surface.

Steve

A.K. Boomer
06-27-2008, 08:56 AM
The material doesn't matter much Brian -- maybe I'm seeing the picture wrong, but it looks like the tail end of the vise is held in place by friction, which means that it can spin around between the gap between the two studs.

If you had used strap clamps in the back, like you did up front, the vise couldn't slide around.



Im with Tattoo mike on this one, Its all friction, unless you have your vise "pinned" or "doweled" to the table, His set-up is beefy as all hell (almost), in fact he's one-upped many of us by having the tail end of the vise clamped in the first place, If the tail is tight there is no way its going to move as thats not where the cutter is exerting force, the vise's jaws are on the other end, Carry on Brian! (exceptin for one thing)
If there's a beef its the vise clamps at the jaw end, I much prefer a direct mount, depending on his anchor height pivots and where his bolts go through on the average he's giving up HALF of his clamping force, (in his case far more than half as you can visually see the bolts hugging the anchor end way too much for my liking) this is a concern as its also where the "action" is, I dont like those kind of vises unless you can figure out a more direct approach to mounting, as far as the tailpiece - all the energies of the two bolts holding it are going directly to holding power, no way that end slips first.

Evan
06-27-2008, 09:31 AM
I see nothing wrong with the setup other than the clamp on the vise is in the way. It isn't likely to move. As for the 1" endmill, that is brass and not steel that is being cut. I routinely use a 3/4" end mill on my mill for all sorts of cuts, especially peripheral cutting in aluminum with good results. It isn't the size of the tool that makes the difference, it's the SFM that matters. As long as the drive can turn the tool at the correct SFM without bogging it will work fine.

SGW
06-27-2008, 09:39 AM
Yeah, I don't see any problem with it. The vise is secured at both ends, so it's not going anywhere. If it were held down only by the strap then there would definitely be a danger of the vise rotating, but that's been taken care of by the other clamps.

If it worked, the 1" endmill is fine. If it was too big the machine would have told you.

lazlo
06-27-2008, 09:41 AM
Its all friction, unless you have your vise "pinned" or "doweled" to the table, His set-up is beefy as all hell (almost), in fact he's one-upped many of us by having the tail end of the vise clamped in the first place,

The strap clamps up front are in the horizontal slot in the vise, so they're physically pinning the vise between them, like they're supposed to be.

The clamp on the back is just pulling down on top of smooth metal. Look where the studs are -- they're 2 inches away from the vise. It's the equivalent of putting the stud on a strap clamp as far away from the workpiece as possible. As you tighten the studs, they're going to bow the clamp, and it will be holding on just the edges of the vise...

That's the first rule of milling machine setup in every introductory machining text: put the pull stud as close to the workpiece as possible:

http://its.fvtc.edu/machshop3/images/mill/rvwclmp10.gifhttp://its.fvtc.edu/machshop3/images/mill/rvwclmp7.gif

Brian, here's a brief online description of basic milling machine setup:

http://its.fvtc.edu/machshop3/basicmill/WorkHold.htm

Willy
06-27-2008, 10:25 AM
I'm sure Brian will be the first to agree it isn't pretty, but he is just making the best of a bad situation. I would suspect he will use something a little less cumbersome next time around.

However mechanically it should be quite sound and secure.
I haven't done the math or looked at any charts, but I would suspect that Brian not knowing what to expect would probably have the nuts on the hold down studs torqued fairly snug. Even with about 30 ft lb torque on each nut, he would i suspect, have 10-15 thousand pounds of combined clamp load on that end. This in conjunction with the other end being properly secured is more than enough to hold anything Brian's mill is capable of throwing at the setup.

But I do agree with Robert in his quest to be safe in clamping procedures though, and do give setups a lot of thought as to where the loads are and what might happen. Once the sh*t hits the fan, and pieces are flying, is no time to rethink your setup.:eek:

Edited to add: Lazlo you beat me with your addition to your post...excellent link and good illustration explaining where the clamp loads end up.

A.K. Boomer
06-27-2008, 10:51 AM
The strap clamps up front are in the horizontal slot in the vise, so they're physically pinning the vise between them, like they're supposed to be.
So what, their doing it with less than 1/2 the clamping pressure

The clamp on the back is just pulling down on top of smooth metal. Look where the studs are -- they're 2 inches away from the vise.
It's the equivalent of putting the stud on a strap clamp as far away from the workpiece as possible.

Its not the equivalent of putting the stud on what your calling a strap clamp as far away from the workpiece as possible, One changes leverage ratio's the other does not, big diff. ---- it is only if your clamp on the rear is so cheesy that it bows to the point of changing its bolt hole tolerance by means of them getting closer together to the point of the bolts then getting side loaded by the tables slots and slot nuts --- now your losing direct pull and some is getting sucked up in vectors, otherwise 100% goes to holding the vise.


That's the first rule of milling machine setup in every introductory machining text: put the pull stud as close to the workpiece as possible:

http://its.fvtc.edu/machshop3/images/mill/rvwclmp10.gifhttp://its.fvtc.edu/machshop3/images/mill/rvwclmp7.gif



Now your cooking, this is what I brought up as the #1 concern earlier.

;)

pcarpenter
06-27-2008, 10:56 AM
Now that he has the mill working, there is no need for him to keep making the best of a bad situation. He can make the right kind of vise clamps and get rid if the I-beam on the back end.

I agree as I have stated before that that vise is not the right tool for the job. Its not however, huge compared to the mill and a typical mill vise for that size mill will be even bigger. Think of the typical Kurt vise on a Bridgeport mill. Its that big too...it just usually gets installed the other direction with the tail hanging off the table for easiest use.

Here's an old pic of my mini-mill with a 3" vise from Little Machine Shop. It works great and seems to be a good fit for the mill.

Paul

http://i108.photobucket.com/albums/n16/pfcarpenter/Machinery/minimill1Medium.jpg

A.K. Boomer
06-27-2008, 10:58 AM
Brian, in order for you to achieve proper leverage ratio's of your pivot clamps in such a short holding area sometimes you can use much longer ones and mount them diagonal to the table, you place your height anchor way out to the sides and run the holding tip across a slot, the result might be a nice leverage change like 66% going to vise load rather than Visa-versa (no pun intended:p )

lazlo
06-27-2008, 11:08 AM
Now that he has the mill working, there is no need for him to keep making the best of a bad situation. He can make the right kind of vise clamps and get rid if the I-beam on the back end.

Agree completely Paul. I have the Japanese version of that same 3" grinding vise, and in Brian's vise thread, I recommended that he make a set of strap clamps with a nose piece thin enough to fit into the horizontal slot. It's a 15 minute job on the mill -- I just used 5/16" (IIRC) cold-rolled plate that's the same width as the slot in the grinding vise, beveled the nose, and cut slots in the back half.

You can also vastly improve the clamping setup by rotating the vise 90, so you can move the pull studs next to the vise. It's hard to tell from his picture, but it looks like his front strap clamps have the studs in the back (due to the t-slot spacing in the mill table).

pcarpenter
06-27-2008, 11:33 AM
Here's a way to make them from simple angle iron...although in the case of a vise like the griding vise, you have to have enough room out to the side to allow for the width of the bolt head. Still, its a simple item to just take a piece of bar stock and mill a groove at the edge just slightly less deep than the thickness of the vise "ledge" as you suggested.

In the picture below, they are really just a way to allow an easy way to quickly re-position my Heinrich drill press vise. Without a sliding table as on a mill, its necessary to be able to move the vise relative to the DP table to position the work correctly. I found that these helped with situations in which the vise ended up with the bolt heads and washers out near the edge of the bolt flanges. I didn't want to risk breaking off an ear.

Paul

http://i108.photobucket.com/albums/n16/pfcarpenter/Tooling/Heinrichviseclamps.jpg

A.K. Boomer
06-27-2008, 12:32 PM
You can also vastly improve the clamping setup by rotating the vise 90, so you can move the pull studs next to the vise. It's hard to tell from his picture, but it looks like his front strap clamps have the studs in the back (due to the t-slot spacing in the mill table).


I was wondering why he didnt do this in the first place (but then again - he would have to let go of that other anchor point:p So maybe he's got his reasons)


What I would do is build two very strong clamps for mounting in the "normal" direction, these clamps would incorporate a stud slot right next to the vise - they would then extend about four times the length out to each side and branch into two precision flat sections with lots of surface area to catch a fore and aft table rib. If he wanted to get ultra rigid with it he could make two sets and use a the entire fore and aft slots -- the vise would be bombproof and there would be minimum bulk.

Edit; precision measurement of both the vise holddown height and the mounts height and table flat area is crucial -- (or you will leave line indents into your table surface) or you could go extravagant and have a built in pivot end for the end of the mill table surfaces.

heidad01
06-27-2008, 02:18 PM
Here is a link that shows the proper clamps to hold one of those vises to the mill table.
http://www.littlemachineshop.com/products/product_view.php?ProductID=2675&category=

Little machine shop.com has them and you can order these, but I suggest you look at the idea and make them yourself now that you have a mill. They are simple enough to make. Also, I'd mount the vise on the table the other way around so that the solid jaw is on the back side of the table like one of the other posters showed in his picture. DavidH

brian Rupnow
06-27-2008, 02:26 PM
Heida01--- Thanks a million for that link. I searched for an hour yesterday and couldn't find that.--Brian

lazlo
06-27-2008, 02:46 PM
Here is a link that shows the proper clamps to hold one of those vises to the mill table.
http://www.littlemachineshop.com/products/product_view.php?ProductID=2675&category=

There are two versions of that grinding vise: one has a row of holes in the base for clamping, and the other type (which I have) has a horizontal slot.

That style clamp is made for the grinding vise with the row of holes.

brian Rupnow
06-27-2008, 04:16 PM
Lazlo---mine Has The Slot Like Yours---what Do You Use For Clamps?

lazlo
06-27-2008, 06:07 PM
Brian, six posts up: :)
http://bbs.homeshopmachinist.net/showpost.php?p=365100&postcount=16


I have the Japanese version of that same 3" grinding vise, and in Brian's vise thread, I recommended that he make a set of strap clamps with a nose piece thin enough to fit into the horizontal slot. It's a 15 minute job on the mill -- I just used 5/16" (IIRC) cold-rolled plate that's the same width as the slot in the grinding vise, beveled the nose, and cut slots in the back half.

I can take some pictures if you'd like, but they're very straight-forward.

dockrat
06-27-2008, 07:14 PM
Brian...my vise is slotted like yours. I just milled out and slotted some 1.5"x1.25" keystock I had on hand.

http://i253.photobucket.com/albums/hh67/Dockrat1/IMGP1070Medium.jpg

.

brian Rupnow
06-27-2008, 08:03 PM
Brian...my vise is slotted like yours. I just milled out and slotted some 1.5"x1.25" keystock I had on hand.

http://i253.photobucket.com/albums/hh67/Dockrat1/IMGP1070Medium.jpg

.
DOCKRAT- Thats exactly what I needed!! Thank you.

A.K. Boomer
06-27-2008, 08:56 PM
I would trust Dockrats set-up over these http://www.littlemachineshop.com/pro...2675&category=
anyday,
much more beefy, note Rats elongated grooves so he can scoot as close to the vice as possible with his stud - he's catching the fore and aft table surface, only thing I can add to that is if the entire unit is built longer but with the slots in the same place it puts extra load on the vise and not on the mills table -- a win win,
but im picky when it comes to clamping stuff down, perhaps to the point of overkill, perhaps also because Iv sometimes loaded things unexpectedly without intention:o (anotherwords -- its good to make things "foolproof" when dealing with myself:p)

oldtiffie
06-27-2008, 10:00 PM
Brian.

You have lots of common sense and a very good appreciation of mechanics and levers as well as the forces applied by a bolt/nut combination with applied torque - as well as bucket loads of caution and "think first". If I recall correctly, you are also a Consultant ME.

Now, there are two arguments or propositions here - almost diametrically opposed and about to get polarised.

The first is that the major part of the clamping force should be directed to the item to be clamped and the least/lesser to the (usually) mill table via the "packing". That is sound practice.

The LittleMachineShop.com clamps at
http://www.littlemachineshop.com/products/product_view.php?ProductID=2675&category=
go counter to that as the lever arms are reversed to the previous proposition - but they work very well. That is sound practice as well.

The so-called "ideal" of having the clamping "bar" (lever?) "horizontal" is OK but not always practical. I'd be wanting the "packing" end to be higher (just a little bit) than the "job/work-piece" end to ensure that the "nose" of the clamping/job end was "inside" the edge of the job ie "sloping down-hill from the clamp end to the job end". That is my ideal - as the bar/lever will bend slightly under the bolt load. But that ideal may not be met on the job either so I have to make the best of what I have on the day/job.

If I have any doubt, I just put some newspaper (a single sheet) on the table and put the vice/job or what-ever on top of that and clamp it. Oiling the paper helps at times too.

If in any doubt, just give the item to be clamped a good "bump" with ball of your hand while turning your hand back at the wrist. It is one of the best "dead-blow" "hammers" about - works well on vice handles too to get that "last little bit" of clamping in the jaws. I also use a bit of 1 1/2" round x about 3" long phosphor-bronze bearing metal rod as well for the same purpose (I've had that "dead hammer" for over 50 years). If the job/vice does not move when those "dead blow" methods are applied it is pretty certain that the job/vice etc. won't move under a reasonable load either.

Last but not least, after all the set-ups, I "try" my mill (or grinder or what-ever) with a hand-fed cut to see how the clamping and machine rigidity and cutter are going to "take it" (or not) and adjust accordingly. I set my power feed (if used) accordingly.

There are a lot of "guides" - most very good for getting an appreciation of the principles involved at least - on just about everything, clamping included. There is no "one size fits all" solution/s - clamping included.

Give several people the same situation on any thing (clamping?) and all may come up with entirely different answers or solutions, and all may "work". To that extent, they are all correct - perhaps some more so and/or better than others - but "OK" none the less.

The final decision is yours (alone). Given your history thus far, I am sure what ever you do will ultimately not only be adequate but will make sense as well.

I'd be quite happy to use that mill of yours with those set-ups you have. Others may differ - as it their right.

Just another note. I'd keep the most milling cutter shank in the collets with the least possible of it extending pout of the collets as I could get to reduce the cantilever on the cutter. The cutter will work better and last longer as well. If needs be, use a smaller cutter or reduce the length of the shank. Make sure that the collet is clear of the radius at the "tooth" end of the shank and engages fully on the shank.

http://i307.photobucket.com/albums/nn294/BrianRupnow/firstmillingjob001.jpg

The machine will "tell" you how it is handling the situation (or not). Just "listen" to it and adjust accordingly.

You are doing very well - "hasten slowly" and eat the elephant with lots of smaller bites.

A.K. Boomer
06-28-2008, 09:45 AM
Tiffer you are kinda long winded --- but thats just because you have so much good advice to give :) -- that was an excellent post full of good practical advice to start out with.