Why can't I do this to gain a length advantage?

[AngelasDad]

Newbie to this forum! I entered my intro yesterday on the meet n greet section. You can see more of my current project there. It's nice to be so warmly welcomed so quickly by some fair-feathered friends!

I'm trying to use my inherited Smithy vertical milling machine to do some work on two pieces of mild steel, rough dimensions of 1/4T X 3/4 X 15.

The supplied vise jaws are only about 4.5 in width, shy of supporting my half-length by about 3".

Why can't I buy some rectangular steel bar stock and cut two lengths, as illustrated by the paper pieces shown in the pic, to add the necessary length support? The end-result finish surface is not absolutely critical, but working with this longer vise jaw length would seem like a possible solution, although I will STILL have to turn my stock around and only work half the overall 15" length at a time.

Otherwise, if I'm absolutely limited to sticking to the 4" vise capacity, I've got to duplicate the milling 4 times along the length of the 15" piece.

Whadaya guys think?

 

[DavidR8]

You can but be aware that the clamping force outside of the jaws will not be as high and there will be chatter when the cutter is cutting outside of the jaws. You can likely get away with maybe an inch on either side of the jaws but past that it will be chatter city.

 

[Cadillac]

Depending on how aggressive you are machining you might be fine with your 4.5 width. You could also put the part to one side of the vise and support the floating side with a jack support. I e also put larger “vise jaws” in to accommodate part size. You can also throw a c-clamp in there if needed?

 

[GeneT45]

I think you'll be fine. If you do experience chatter (unlikely, based on my experience with a Smithy) you could drill holes on the outboard ends of your extensions - one clearance, and one tapped, and use bolts to give some additional squeeze.

The biggest downside I see is that you will lose some precision. Vise jaws are typically ground to close tolerance. Unless you're getting something pre-ground, it will not be *as* accurate. May not matter, but it's something to be aware of.

That's a *vertical* mill, btw.

GST

 

[rabler]

Try it. If it works, it works. If not, try something else or do it in smaller sections. I do lots of things with that approach. There are some general rules of thumb, but ultimately it just takes time to build experience on what works.

 

[AngelasDad]

I think you'll be fine. If you do experience chatter (unlikely, based on my experience with a Smithy) you could drill holes on the outboard ends of your extensions - one clearance, and one tapped, and use bolts to give some additional squeeze.

The biggest downside I see is that you will lose some precision. Vise jaws are typically ground to close tolerance. Unless you're getting something pre-ground, it will not be *as* accurate. May not matter, but it's something to be aware of.

That's a *vertical* mill, btw.

GST

My bad! And thx so much for your input. Horizontal/Vertical You say banana! Ha ha. Oopsie daisy. Thx for the correction.

Yes, in this case, the precision tradeoff shouldn't be a big concern compared to the lesser hassle and also potential loss of precision when moving the piece 4 times!

 

[brino]

My preferences....... remove the vise and put your long work piece directly on the table.
Use t-slot clamping kit to hold it down.
Use four or five clamps and just remove one at a time to mill that section.

Brian

 

[Dabbler]

Yay @brino! This is the best way to mill long sections! There are others, but this is economical, quick, and secure.

 

[AngelasDad]

My preferences....... remove the vise and put your long work piece directly on the table.
Use t-slot clamping kit to hold it down.
Use four or five clamps and just remove one at a time to mill that section.

Brian

I think that won't work for me since my bed is too far away from my milling head. I'd surely be at or near my limits on how far down I'd be lowering my cutter. That beefy vise helps to bring the workpiece up much closer to the cutter so one doesn't need to sacrifice the relative instability of the retractable milling head. Good plan though for different circumstances, thanks!

 

[ChazzC]

Get a (or two, pending what you buy) length of “precision ground flat stock” and clamp the ends with C-clamps. Can often find the stock at reasonable prices on eBay.