work holding small parts

[zerodegreec]

So I am starting to build another one of Elmer's motors. The grasshopper. Now some of the parts are quite small, 4mm square (Roughly). I run a BF20 mill and typically use my 4" curt clone vise. Does anyone have some pics or links to ways to machine small items?

By the looks of the plans this project should keep me busy till the new year

[Mcgyver]

a good quality vise will hold small items, but i know what you mean, you're not going to machine 1/16" pins very easily in a 10" 4 jaw.

There is no single answer, its innovate as the situation requires. solder the piece to a larger piece for machining is one i like, make a finger plate, make/collect small tooling, make/buy a small grinding vise. The tiny little starret vises are sometimes handy. what miniature tooling you make/buy is then easily held in a regular vise

[quazga]

In addition, you can use a fusible alloy such as found here: Low Melting Point Bismuth Based Alloys

And also ICE! Yes, an ice vice will hold small parts very strongly and ice sticks to almost anything. Such as: ICE VICE AFP - freezing clamping system

[zerodegreec]

That is a unique solution...

I think my biggest problem is that I have a hard time cutting/sacrificing material in order to make something else... I have a small budget so the material I have around the shop is not exactly easy "waste" but I obviously need to rethink the use of material and realize that its just part of the process to use materials that will be cut up to make other parts... Just a new way of thinking about the process to make things...

[cncharleydude]

I have had some success in the past with this mitee-grip product, machining very thin parts. Its about .0005 thick and you heat it up in the oven then place your part on it. During machining you can use coolant or air to keep cool. Not sure if this would work for your application.

Mitee-Bite Mitee-Grip

But yeah usually I have to make some creative tooling or fixturing.

[laszlozoltan]

I think you hit the nail on the head with that observation- seriously ! I find waste is one of my greatest obstacles to attend to a project in a forthright manner. Uncut stock is potiential; but when you start taking chunks off of it, you lose that potiential. My solution to that is to always buy 2 or 3 times the material I think I'll need in case there's a problem or I want to try another approach.

[diyengineer]

Originally Posted by quazga In addition, you can use a fusible alloy such as found here: Low Melting Point Bismuth Based Alloys And also ICE! Yes, an ice vice will hold small parts very strongly and ice sticks to almost anything. Such as: ICE VICE AFP - freezing clamping system

That is really innovative! Probably the coolest thing ive seen today haha!

[quazga]

Originally Posted by diyengineer That is really innovative! Probably the coolest thing ive seen today haha!

COOLEST! HAHAHA!

You should also know about right hand cut left hand helix end mills. They cut in the normal right hand direction but their flutes spiral in the opposite direction compared to normal end mills. This causes the stock to be pushed down rather than pulled up which is good for milling something like sheet metal or small parts in certain situations. The draw back though is they are hard to find.

As for preserving stock, with some metals, like various alloys of brass for example, you can save your chips and other waste and melt it down and cast it into various shapes that can then be machined.

[diyengineer]

I plan on saving all my aluminum chips and melting them down in my foundry

I plan on cutting a lot of .063" aluminum sheet metal without a vacuum hold down table. I think these helix bits you are talking about are just what i need. I need the sheet to be pushed down into the plastic throw away board instead of being lifted up. Other then cost, is there any disadvantage to them? The sheet will be fixed on all the outside corners just not in the center so a push down force would be awesome.

Originally Posted by quazga COOLEST! HAHAHA! You should also know about right hand cut left hand helix end mills. They cut in the normal right hand direction but their flutes spiral in the opposite direction compared to normal end mills. This causes the stock to be pushed down rather than pulled up which is good for milling something like sheet metal or small parts in certain situations. The draw back though is they are hard to find. As for preserving stock, with some metals, like various alloys of brass for example, you can save your chips and other waste and melt it down and cast it into various shapes that can then be machined.

[quazga]

Oh! You're the guy modernizing that big Boeing machine. I just watched most of your videos on Youtube the other day. Great work so far setting up your shop!

I don't think there are any other advantages with the right hand cut left hand helix mills other than the aforementioned. One thing for sure is you wont be able to cut that 0.063 aluminum sheet with a normal end mill if you're gonna have any detailed areas. What happens is, let's say you were to make a through cut with a 0.25 mill and then make another through cut 0.5 inches away from the first cut that intersects the first cut at some point after a few inches or so, well what will happen is the instant the cutter breaks through to the first cut the stock will climb up the side of the mill with enough force to bend the stock. No reducing of feeds and speeds will work to prevent this. The only way to have a chance of preventing this without 100% work holding is to use the aforementioned mills.

You can of course, stop just shy of cutting all the way through to the first cut and possibly get away with using regular mills doing this too, but that means you'll have to come back and hand finish all of the fingers that were left in place.

If there are any master machinists reading this and you know of any other tricks to prevent this I would love to hear what you have to say.

[diyengineer]

That's good to hear! At least i can buy a lot of those other endmills haha. hopefully they will work for me. I'm sure it will eventually see a vacuum hold down table in its near future. Hopefully sooner then later!

Thanks for your help!

Originally Posted by quazga Oh! You're the guy modernizing that big Boeing machine. I just watched most of your videos on Youtube the other day. Great work so far setting up your shop! I don't think there are any other advantages with the right hand cut left hand helix mills other than the aforementioned. One thing for sure is you wont be able to cut that 0.063 aluminum sheet with a normal end mill if you're gonna have any detailed areas. What happens is, let's say you were to make a through cut with a 0.25 mill and then make another through cut 0.5 inches away from the first cut that intersects the first cut at some point after a few inches or so, well what will happen is the instant the cutter breaks through to the first cut the stock will climb up the side of the mill with enough force to bend the stock. No reducing of feeds and speeds will work to prevent this. The only way to have a chance of preventing this without 100% work holding is to use the aforementioned mills. You can of course, stop just shy of cutting all the way through to the first cut and possibly get away with using regular mills doing this too, but that means you'll have to come back and hand finish all of the fingers that were left in place. If there are any master machinists reading this and you know of any other tricks to prevent this I would love to hear what you have to say.

[headsmess]

nothing beats working on the floor, the leads of several power tools wrapped around you, sitting on top of the file as you try clamping that pesky lil piece of brass down cus you spent three hours getting it to this point but forgot to put one critical hole through it before parting it from that last bit of bar that was only just long enough in the first place.... while trying to ignore the monster outside demanding you mow the lawn... cant they see youre fixing the mower?


mmmm, machining....

on the serious side...it all comes down to jigs. and storing those jigs. once that parts sorted, the rest just flows. the device to make this part is right here, works like this, and goes back when its done!

but you can not make something of any worth with inferior equipment.

call us hoarders, but every good machinist should go into catatonic shock when they go to the scrapyard and see what some people actually throw out! *proud owner of a vari-ac and magnetic chuck*