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Thread: How to shorten a Sinar rail?

  1. #11
    Drew Wiley
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    Re: How to shorten a Sinar rail?

    Les - the rail contains steel. A table saw would be dangerous in any event. That's how people lose a hand or eye or worse. Steel can be cut if firmly clamped into a "chop saw" with either a metal-cutting abrasive wheel in it (typically 14-inch diameter), or a special steel-cutting kind of carbide blade on the same kind of chop saw. Don't confuse this with a wood-cutting mitre saw; using one of those could also result in serious injury. Hacksaws are for hacks. Sloppy, crude, and archaic; but if precision and neatness of cut is not the objective, yes, it would work. The company I worked for started out as a supplier to the Navy (there were big military shipyards all around here back then). I sold them very few hacksaws, but thousands of heavy-duty metal-working power tools over the years. Most metal working shops and even some plumbers have clamping stands for portable power bandsaws (essentially a power-hacksaw, not to be confused with wood-cutting bandsaws) which would work, but not nearly as well as a rotating "chop saw". But there is proper technique to all of this; otherwise a person can get seriously hurt.

  2. #12

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    Re: How to shorten a Sinar rail?

    So... Last year I acquired a Little Machine Shop Mini Mill. This was probably project 12 or so, and finally I feel comfortable operating (100% self taught) the mill.

    Took the rail apart.
    Shortened the round rail. I did this by rotating the round rail in the vise and making 4 shallow cuts.
    Measured the depth of the thread and shortened the central rod and rethreaded the end.
    Shortened the top rectangular rod to size and drilled a hole in it and into the round rail.
    Threaded the hole in the round rail.
    Reamed out the hole in the square rod to countersink the screw.
    Re-assembled the Rail.

    Awaiting a 3/32" end mill ($6.95) to cut the grove for the pin of another rail to fit in.

    The hardest thing was to find a correctly sized Phillips screwdriver to correctly fit inside the 2 screws! The screws initially were very hard to turn, to me looks like dried out thread sealant.

  3. #13
    Tin Can's Avatar
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    Re: How to shorten a Sinar rail?

    Hurray for DIY!



    Quote Originally Posted by Greg View Post
    So... Last year I acquired a Little Machine Shop Mini Mill. This was probably project 12 or so, and finally I feel comfortable operating (100% self taught) the mill.

    Took the rail apart.
    Shortened the round rail. I did this by rotating the round rail in the vise and making 4 shallow cuts.
    Measured the depth of the thread and shortened the central rod and rethreaded the end.
    Shortened the top rectangular rod to size and drilled a hole in it and into the round rail.
    Threaded the hole in the round rail.
    Reamed out the hole in the square rod to countersink the screw.
    Re-assembled the Rail.

    Awaiting a 3/32" end mill ($6.95) to cut the grove for the pin of another rail to fit in.

    The hardest thing was to find a correctly sized Phillips screwdriver to correctly fit inside the 2 screws! The screws initially were very hard to turn, to me looks like dried out thread sealant.
    2022

  4. #14

    Re: How to shorten a Sinar rail?

    “The secret of getting ahead is getting started.”
    ― Mark Twain

  5. #15

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    Re: How to shorten a Sinar rail?

    Shortening a Sinar rail is more involved than it appers.

    The alignment bar is made of hard stainless steel, Rail is aluminium alloy. If an attempt was made to put the complete rail into a circular saw with a carbide tipped blade, moment the carbide tip touches the hard stainless steel, the carbide insert will shatter producing a lethal projectile with random direction. This is stuff ya NEVER do in a shop.

    Shortening the rail requires taking the rail apart, cutting the aluminum alloy rail tube seperate from the stainless steel bar on a metal band saw. Once this is done, the cut off rail tube needs a trip and spin on a lathe to clean it up and machine the features to accommodate the internal rail parts. The stainless steel bar will need a trip to the milling machine to clean up the ends and make the alignment pin or slot depending on how the Sinar rail needs to function. A new set of alignment retaining holes must be added to the shortened rail to properly support the alignment rail.

    Only way to do this properly is with machine tools, proper tooling and machine tool skills and related.

    Here are the residual bits from a Standard 12" Sinar rail that has been shortened about 4". The left over rail bits can be made into a very short Sinar rail.
    Click image for larger version. 

Name:	Sinar Rail, shorted.jpg 
Views:	29 
Size:	100.4 KB 
ID:	215852


    Bernice

  6. #16

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    Re: How to shorten a Sinar rail?

    Sinar used both hex socket head and phillips head screws on the alignment rail. They are size M3, think the length is 8 or 10mm ?
    The Phillips head screws are Sinar special as the head outside diameter is smaller than ISO standard. Suggest using the standard M3 socket head cap screw or a Low head socket head. These are common off the shelf items.

    Sinar is fond of Loctite as part of their assembly process. This makes taking Sinar stuff apart difficult, but prevents screws from working loose then falling out.
    Heat up the threaded bits to break the Loctite bond before trying to take Sinar bits apart. The risk of ripping out the screw drive head is very real and easy if this is not done.


    Bernice


    Quote Originally Posted by Greg View Post
    The hardest thing was to find a correctly sized Phillips screwdriver to correctly fit inside the 2 screws! The screws initially were very hard to turn, to me looks like dried out thread sealant.

  7. #17
    Drew Wiley
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    Re: How to shorten a Sinar rail?

    Jet also has a very nice small milling machine, the Hobby Milling Machine, around the same price. It came onto the market long after most of my own projects were finished, but I've had a floor-standing old Jet industrial drill press around a long time.

  8. #18
    Drew Wiley
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    Re: How to shorten a Sinar rail?

    Right, Bernice. Steel-cutting carbide blades are a very different kind of carbide with a negative rake angle. And they're not supposed to be made in common wood mitre box sizes either, with similar arbor size, though unscrupulous importers do offer those. Different RPM's too (vitally important). A shed carbide tooth can be just like a bullet. I've seen embedded deep into wooden beams across a room. I just finished cutting some aluminum on my mitre saw. The blade itself cost twice as much as the saw - true industrial quality - and it's a way more solidly built saw that any made today, including the massive clamps. And I always keep around full-face shields if needed, and not just safety glasses. Handheld circular saws should never be used for this kind of purpose, though I did sell a lot of early cordless ones with thin steel-cutting blades to the Fire Dept. They can grab one those, run up to a door, and slice through the deadbolt faster than a chainsaw could be fired up to cut through the door itself.

    My portable Metabo grinder would slice through that Sinar rail in seconds; but it's awfully difficult to hold square, and darn easy to get injured with if someone isn't experienced with them. Lots of those are used to cut apart into scrap metal old WWII ships out in the "mothball fleet" upriver; just a few ships remain. It might have been 200 a decade or two ago. Bridge ironworkers use em too, along with Fein grinders. You get what you pay for. Sawzalls are also hypothetically usable but won't give a straight cut. I sold more Sawzall blades in one outlet than everyone else in northern California combined; it was unbelievable. Some of those would cut through a Sinar rail in mere seconds too - but what a ragged mess at the cut end! These days I use mine mainly for trimming smaller tree limbs.

  9. #19
    Les
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    Re: How to shorten a Sinar rail?

    Maybe I didn't explain it fully. I had no desire to use a carbide blade for this (and never implied), but a metal disk cutter....v. similar to my hand grinder. Not having a proper way to hold the piece, the table saw offers both....the cutting and holding.

    Drew, just because you'd not attempt it, it does not mean that this can't be done safely. Just to add, the cross cutting channel for the miter gauge on my saw is not a conventional type....it locks under the the surface of the table and unable to pop out.

    Les

  10. #20

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    Re: How to shorten a Sinar rail?

    Quote Originally Posted by Daniel Unkefer View Post
    My Little Machine Shop Mill is the model 3990. I can recommend it 100%. Only modification was to make different sized front plexiglass shields.

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