Large slot milling on an X2 type mill

[Bernd]

Here's a tip for you guys with a X2 mill.

I had to cut a 3/8" wide slot into a piece of steel that is 1.25" thick. Now that's quite a bit of metal to be removed for such a small mill. I solved the problem by chain drilling, then using a 3/8" dia. end mill to mill out the webs left and finally took a smoothing cut on both sides. Here are some pics of how I did it.

First I drilled 3/8" holes spaced 1/2" on center.

Then I milled out the web between the drilled holes. This was a very touchy cut. The machine jumped and vibrated all over the place until I found the right speed and manual feed rate. I made sure the Z-gib was very tight.

This is what it looks like when all the webs are milled out. Now for a bit of side cutting to clean up both sides of the slot.

And here is the finished product.

This slot will have an aluminum tool holder installed with a HSS cutter. I'm making a large boring tool. When I get it completed I'll post a pic. It'll be used in my Buffalo Drill press for making drag car motor plates. I'll explain when done.

Bernd

 

[mklotz]

Bernd,

When I've done what you're describing I take out the webs by plunging with an endmill to cut away one web at a time before doing the clean up cuts. This produces a lot less vibration than trying to remove the webs with a longitudinal cut.

 

[kustomkb]

Hey Marv, i think you just made the 30,000 th post!

 

[mklotz]

So, what did I win?

 

[Bernd]

Bernd,

When I've done what you're describing I take out the webs by plunging with an endmill to cut away one web at a time before doing the clean up cuts. This produces a lot less vibration than trying to remove the webs with a longitudinal cut.

I didn't quite explain it that way Marv. But that's exactly what I did. If you look closely at the third pic down you'll see that I did a z axis cut with a 4 flute mill. The darn little mill still jumped and chattered all over the place but it worked. Thanks for putting that into words that will be understood. Sometimes I'm not that eloquent with words.

Wish I could have waited till the Bridgeport was back together,but the job this is going to be used on can't wait that long.


Bernd

 

[Bernd]

As promised. I've got the tool complete to give it a try. Here's what the finished tool looks like all assembled.

Partially assembled tool. The aluminum tool holders backside.

Aluminum tool holder mounted in arm.

Backside showing how it's fastened for now.

Over all pic showing how the tool will be used to clean up the sides of a 14" dia. Hole.

Closer view of tool.


These plates are used between the motor and transmission of a drag race car. There is also a front plate. These plates are fastened to the frame of the car. It keeps the engine from tearing itself out of the motor mounts.

The large hole in this plate is for clearance of the torque converter. I'll rough cut that part out with a jig saw and then use this tool to smooth up the sides. Perhaps I'll post a couple of pics when I actually do a plate.

I know this has nothing to do with steam engine building, but I believe it gives a good idea of tool design and building. If that's what you want to call this. :big:

Bernd

 

[rake60]

I know this has nothing to do with steam engine building, but I believe it gives a good idea of tool design and building. If that's what you want to call this. :big:

Bernd

I'd call that a perfect example of making what you need from what you have.

Congrats on a well done project.
That tool even looks like it wants to cut metal.
I won't comment how dangerous it looks.
Be careful!

Great Work!

Rick

 

[CrewCab]

Well I'm enjoying it Bernd, to be fair I've got that many tool builds on my "TO DO" list I am likely to be busy for evermore

That's one "large" boring tool, by our standards anyway, one question, (just for my education really) ........... I presume your drill press will swing this pretty slowly so finishing off the bore will be a steady job, but as there's no drawbar how do you get the darn taper to grip well enough for something this size

and can I say ............. I admire your determination in roughing out a 14" hole with a jigsaw particularly as I assume the plate is probably 3/8" thick steel :bow:

............. so .......... not that I'll be around to help ......... but if you let us know when your planning to attack the plate I'll certainly raise a glass in your honour

and please make sure you take plenty of photo's .............. if you can manage this with a drill press I can't wait to see what you get up to with the Bridgeport 8)

Take care

CC

 

[Loose nut]

Wouldn't a slot mill work better, without predrilling holes, that way you don't have to worry about milling through the jaggy bits that cause the vibration. If you don't have a slot mill, drill an under size hole near one end and plunge a regular endmill down directly over the hole, take a cut , back up to the hole and repeat until complete. If the slot has to be dim. accurate then use an under size endmill to rough it out and a "on size" one for a final finish cut.

 

[CrewCab]

The machine jumped and vibrated all over the place until I found the right speed and manual feed rate.

I have to say, in my short time being associated with an X2 that one of it's main qualities is ........... letting you know when you ask a little too much : ............ it's very good at that ........... though to be fair it will then press on and do it's best to achieve the task 8)

In short it's a game little beggar ;D

CC

 

[Bernd]

Let's see if I can answer all those guestions.

Rick,

Yes it looks dangerous, but the rpm is very low. We're talking less than 50rpm. And I keep my nose far enough away not to get caught by the tool. :big:

CC,

Boring tool? I guess you could call it that. All it needs to do is make a nice looking hole. Not something that looks like a rat chewed on. :big: They make tree panning tools to cut large wood circles. That tool is held be a drill chuck in a tapered spindle. This would be pretty close to that concept.

As for speed, I don't think I'll be running over 50rpm. Believe it or not I've already tried this before. I think I posted it here once before I moved the drill press into the basement. That taper will actually hold the tool. Also since you are aplying a downward pressure it will hold the tool in the taper.

The plate is 1/4" aluminum. I will use a hand held jig saw with a wood blade. I've already tried that. It's a big noisy but will work. It's the best I've come up with so far. I've tried other methods without success.

Perhaps I should put a thread in the general when I do one of these plates. Remember that what I'm showing here can be down scaled for use in building a steam engine.

loose nut, CC,

I don't have a slot mill or 2 flute cutter of 3/8" dia. so I had to use a 3/8" 4 lip end mill. The hole was drilled 3/8" and a 3/8" end mill was used. Slot size didn't matter. I made the aluminum tool holder to fit the slot. I think I just over taxed that poor small mill. I'm sure I was way over what it was designed for.

I know one thing. Once the Bridgeport is up and running I'll be doing that plate on that machine. Right now it takes two drill presses to do this job.

Bernd

 

[CrewCab]

Thanks Bernd, I understand the logistics a lot more now ........... good luck feller ;D and I really look forward to updates to this thread 8)

CC

 

[ksouers]

At first I thought is was going to be a giant fly cutter

I've used similar tools to make large holes in wood (about 8 inches), and cut out large diameter disks. Terribly unbalanced little buggers. This is going to be interesting.

 

[wareagle]

These plates are used between the motor and transmission of a drag race car. There is also a front plate. These plates are fastened to the frame of the car. It keeps the engine from tearing itself out of the motor mounts.

The large hole in this plate is for clearance of the torque converter. I'll rough cut that part out with a jig saw and then use this tool to smooth up the sides. Perhaps I'll post a couple of pics when I actually do a plate.

Bernd, we have more in common than you may think! I grew up drag racing. Loved every minute of it. These days, I have strayed from going straight. These bad boys are what I been messing with for the past several years. The video isn't me, just a decent one I dug up real quick to give you a virtual ride. ;D

[ame]http://www.youtube.com/watch?v=hFXzDVzMPvQ[/ame]

EDIT: Just come accross this one. Thought I'd share the rough part, too!
[ame]http://www.youtube.com/watch?v=6nrHZOE2P0o[/ame]

Back to your tool... It should do the job. This goes without saying, but make sure you have the plate firmly clamped! Witht he cutter that far fromthe spindle, there will be a lot of force applied to the plate through the cutter! BTW, Nice job on it!

 

[Bernd]

Pretty neat there WE. I always wondered what it would be like in the cockpit of one of those.

I've done this before and believe I posted it here somewhere but can't remember were. Might have been in the general section. I'll have to look.

I'll put up a post on how I do these shortly. This process can be scaled down to a boiler build such as Firebird is doing in cutting out the holes for his copper tube to fit in or any odd sized holes that need to be cut in thin material.

Bernd

 

[Lew Hartswick]

I think I'd have put a counter balancing weight on the back end to, at least help reduce any shaking
due to unbalance. Nice machining job.
...lew...

 

[Bernd]

Lew,

At the speed I run it at there is no shake, but if I crank the speed up to say about 150 or 200 RPM the whole drill press starts to shake back and forth. Since I'm only going, probably under 50rpm, I won't need a counter balance.

Thanks for the finish comment. The steel parts were surface ground to make them look good. 8)

Bernd

 

[Bernd]

Finally found the thread where I show the drill press still in the garage and my first attempts at cutting that 14" dia. hole in the 1/4" alumnim plate.

Here's the thread. http://www.homemodelenginemachinist.com/index.php?topic=1503.0

You can see that it did work, but not very good. Hence the new designed tool.

Bernd

 

[Bernd]

This is the last installment for this project. The weather was bad out there today so I decided it was time to get this project finished and see if the tool I made will work. So on with the show.

First I needed to make a wooden mounting surface for the aluminum plate and bolt it to the drill press table. I made four 2" X 4" blocks (they're under the wooden table) to lift the wooden table up high enough to clear the bottom of the tooling. Here I'm lining up the hole in the table with the spindle. I used a plug in the table and the hole in the bottom of the tool to roughly center the table. Then I drilled 4 holes to correspond with the drill press table slots.

Here you can see the carriage blots used to hold down the MDF table. I'm checking to see if I can get 14.5" dia. Out of the tool or weather I needed to make the slot longer. It was Ok.

Here I'll show how I locate the holes to some semblance of precision. The person I make the plates for had a 1/16" thick steel plate cut on the laser for a template of were the holes are needed.

I made transfer punch using a bit of round aluminum. I turned a small spigot at one end a little less than 1/16" long. The rod is a piece of drill rod with a point on the end.

I put it in the hole on the template and give it a good tap with a hammer .

And that goes for all the holes in the plate. The holes are 3/8" dia. By the way.

Here are the holes that will be needed in this plate. I mark them so I can remember what size drill to use in what hole.

I quickly made a temporary trammel to mark the 14.5" dia. circle I need to cut out. Plus it'll help me line up the plate on the drill press table.

I marked a line with a black marker were I'm going to use the saber saw to cut out the waste portion.

Well, 4 saw blades later and enough noise to wake the dead I had the center cut out. This is not going to work. I need to find another method to cut out the waste.

I've lined up the plate and started the first cut.

The semi finished product. I still need to drill the bolt holes, 2 dowel holes and the hole for the starter.


After several false starts on the cutter I finally got a cutter that worked somewhat. I tried different clearance angles and positive rake, 0 rake and negative rake on the cutting face. Negative rake seemed to work pretty good. I did discover that the tooling is stiff enough for the job, but the drive train of the drill press is to loose. I get quite a bit of chatter. I think the slowest rpm that the machine ran was about 5 rpm. That is were it seemed to be the quietest.

Using this tool as a boring bar did not work quite like I had expected. Next try will be making the tool into a rather large tree panning tool. That way I can support the tool on the bottom and cut the center waste out in one cut and be done with it.

So it's back to the drawing board for the next tool design. I hope to do these plates on the Bridgeport some day. Should be a lot easier than on this drill press. But sometimes you press into service what ever looks like it will work.

Bernd