[Magnum164]

This could probably go in another forum, but wanted to get some opinions from other Tormach owners. I am machining batches of 6mm x 6mm x 23.5mm spacers, which have threaded thru holes in one side and each end is also threads. For the end holes I have no choice I don't think but to create a fixture and drill/thread one by one.

For the prototype and approval I machined these one by one (5 total for proofs). So now I need to make a batch of about 30. Since all I have is plate, i decided to just lay the parts out and do 10 at a time. The last cut cuts the parts around the perimeter and they drop off.

For those that have been doing this a while is this the best way to do these parts? The .25 plate is machined to thickness first, but I could leave it a hair thicker and machine the bottom off. Problem is I am not sure how well that works.

Am I better off machining end to end then flipping and machining the bottom, the vise should hold the parts, then I can drill/tap the ends.

[rowbare]

I think your approach is workable. If you find that the parts aren't falling away cleanly when you cut them off, you could put a small bar of say plastic or wood underneath with some double sided tape to hold the parts. This only has to be the width of the part and the length of your stock.

As to the threaded holes on the end, you could clamp the stock in the vise edge up and drill and tap the holes on both edges of the raw stock. Drill deep enough to make it into the spacers. You could drill the part of the hole that is in the waste stock oversize for chip clearance though it might not be necessary especially if you are using form taps. Once you have done that, you can lay the part down and do the last of your holes and the profile cut. This would be easiest if you have a vise stop.

bob

[Geof]

Your picture implies that you are cutting the rectangular pieces out inside a sort of pocket. I foresee a potential problem; just before they fall off they may bend slightly making contact with the side of the pocket and then jamming against the cutter.

Here is an alternate suggestion which could save some handling time.

Do all the tapped holes first in all ten, face the top if that is needed.

Drill an identical pattern of holes in a piece of cold rolled flat bar slightly larger than the overall size of material need for the ten pieces.

Bolt the tapped material to the flat bar, grip that in the vise, machine the perimeters of the ten parts and face the top if that is needed.

Now hold the whole assembly edge on in the vise and tap the holes in one end, then turn it over and tap them in the other.

Remove ten finished parts.

[Magnum164]

Thanks for the suggestions, some good ideas. For now the quickest way is to mount a plate vertical as shown in this pic. I had a little more material in this pick as I am still cautious about machining so close to my vise. Ordering some material for soft jaws, the ones I ordered would not fit then I won't worry about nicking those.

I just fliped this over then machined the bottom and all was well. Now just need to machine the soft jaw I do have to make a jig for drilling the end holes. Machining vertical like this is going by a lot faster - less setup time. Prep time on plate is the same for either process right now.

[benji2505]

turning the pieces around and facing off some remaining stock on the bottom works well. It is necessary to clamp the pieces themselves though, so you have to remove all stock around the (future) pieces. Repeatability in all 3 dimensions is very good, you should be able to tap after facing off the bottom.

benji

[Magnum164]

Actually turns out a lot easier than the other way I was doing it. Guess you learn the more you do. Almost every piece is identical and I did clamp the pieces themselves.

[benji2505]

I was referring to your first picture, when I mentioned the clamping of the pieces itself - no offense

we reach repeatability within +/- 1 thou in the z-axis/ part height. being clean from chips and fluid in the vise and a consistent down-pressure of the pieces onto the parallel help.

[Magnum164]

I was referring to your first picture, when I mentioned the clamping of the pieces itself - no offense

we reach repeatability within +/- 1 thou in the z-axis/ part height. being clean from chips and fluid in the vise and a consistent down-pressure of the pieces onto the parallel help.

Ah ok I understand you. Actually I have more parts which will have to be done probably like you mentioned.

[Magnum164]

Your picture implies that you are cutting the rectangular pieces out inside a sort of pocket. I foresee a potential problem; just before they fall off they may bend slightly making contact with the side of the pocket and then jamming against the cutter.

Here is an alternate suggestion which could save some handling time.

Do all the tapped holes first in all ten, face the top if that is needed.

Drill an identical pattern of holes in a piece of cold rolled flat bar slightly larger than the overall size of material need for the ten pieces.

Bolt the tapped material to the flat bar, grip that in the vise, machine the perimeters of the ten parts and face the top if that is needed.

Now hold the whole assembly edge on in the vise and tap the holes in one end, then turn it over and tap them in the other.

Remove ten finished parts.

I was reading through this as I have another complicated part to hold. I must have not read this post correctly. Actually, what you are suggesting would probably save me a LOT of time.

[Geof]

Yes, this approach does save a lot of time, my company uses this type of multi-part clamping/fixturing all the time. Actually we have progressed beyond holding things edge-on in the vise to do end features and now have numerous machines outfitted with rotary fixturing. This allows all the operations; perimeter, facing top and drilling end holes to be done in a single fixturing. When a production run is fewer than a hundred parts the rotary fixture approach is overkill but when the part count is in the many hundreds or thousands the time saving really adds up.