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Setting up slitting saw for round stock?
Is there a "kink" for setting up a slitting saw to saw through
round bar stock along the axis, so that the slot is exactly across a diameter? (I presume this to be a similar problem to setting up accurately for cross-drilling) This is actually a Ham Radio application; I wish to make up some very large banana-type plugs from the 1/4" round bar stock that I have in small quantities. For this, I will need to saw two diameters in a cross shape, and then splay out the leaves slightly to make a springy and rubbing contact. |
"Airy R.Bean" wrote in message ... Is there a "kink" for setting up a slitting saw to saw through round bar stock along the axis, so that the slot is exactly across a diameter? (I presume this to be a similar problem to setting up accurately for cross-drilling) This is actually a Ham Radio application; I wish to make up some very large banana-type plugs from the 1/4" round bar stock that I have in small quantities. For this, I will need to saw two diameters in a cross shape, and then splay out the leaves slightly to make a springy and rubbing contact. I put the saw mandrel in a lathe chuck and made a block with a hole and setscrew to mount on the cross-slide. Did this to slit the threaded end of a bolt - it has a countersunk hole lengthways through it and when a smaller screw is thightened it locks the threads. This bolt is the mount for a ball-turning attachment; I wanted to be able to lock the mounting bolt at the right clearance without having it cock or move sideways, so a locknut and a setscrew were both out. I had to thread the hole through my block, but you don't need that. If you wanted to get fancy you could make a shouldered sleeve with your setscrew holding the stock, drill a hole in the shoulder, and two holes in the block for a pin to set your 90 degree cuts. |
In article , Airy R.Bean says...
Is there a "kink" for setting up a slitting saw to saw through round bar stock along the axis, so that the slot is exactly across a diameter? Just set the part up in the vise, and touch off on one side using something like cigarette paper. Then advance across the workpiece half a diameter plus have the width of the saw blade. That will get you within a few thou, becuase they do cut slightly oversize. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
Thanks for your ideas - it's always the way that there's more
though and effort needed to be put in to make the jig than to make the device in which you're interested! "jtaylor" wrote in message ... I had to thread the hole through my block, but you don't need that. If you wanted to get fancy you could make a shouldered sleeve with your setscrew holding the stock, drill a hole in the shoulder, and two holes in the block for a pin to set your 90 degree cuts. |
"Airy R.Bean" wrote in message ... Is there a "kink" for setting up a slitting saw to saw through round bar stock along the axis, so that the slot is exactly across a diameter? (I presume this to be a similar problem to setting up accurately for cross-drilling) This is actually a Ham Radio application; I wish to make up some very large banana-type plugs from the 1/4" round bar stock that I have in small quantities. For this, I will need to saw two diameters in a cross shape, and then splay out the leaves slightly to make a springy and rubbing contact. Assuming you are using a vertical mill so that the slitting saw is horizontal, and the work is fixtured horizontal (vee block perhaps): a/ Measure height of top of stock with vernier height guage, subtract half the stock thickness, and add half the slitting saw thickness - set the height guage to the resultant figure. b/ Adjust quill of mill so top of slitting saw just touches the height guage and lock the quill. You now have the slitting saw bang on centre of the work. AWEM |
"Airy R.Bean" wrote in message ... Thanks for your ideas - it's always the way that there's more though and effort needed to be put in to make the jig than to make the device in which you're interested! "jtaylor" wrote in message ... I had to thread the hole through my block, but you don't need that. If you wanted to get fancy you could make a shouldered sleeve with your setscrew holding the stock, drill a hole in the shoulder, and two holes in the block for a pin to set your 90 degree cuts. If you're making more than half a dozen it'd be worth it. |
Airy R.Bean wrote:
Is there a "kink" for setting up a slitting saw to saw through round bar stock along the axis, so that the slot is exactly across a diameter? (I presume this to be a similar problem to setting up accurately for cross-drilling) This trick assumes you have the slitting saw in a vertical mill, the bar is horizontal, and the slitting saw teeth are straight (i.e.. not staggered like a wood saw blade). Adjust the position of the bar and saw so that, by eye, the blade is just about touching the fattest part of the bar. Interpose a vertical 6" steel rule between the bar and the saw and move the table to very gently pinch the rule. Unless you were lucky and set the saw exactly on the fattest part, the rule will no longer be vertical. Adjust the hight of the saw until the rule is truly vertical - you will be amazed at how accurately the blade is then at centre hight. -- Regards, Gary Wooding (To reply by email, change feet to foot in my address) |
Now, that's interesting, because it is a variation of the technique
for setting up for cross drilling (except that then the ruler is in see-saw mode) "Wooding" wrote in message ... Airy R.Bean wrote: Is there a "kink" for setting up a slitting saw to saw through round bar stock along the axis, so that the slot is exactly across a diameter? (I presume this to be a similar problem to setting up accurately for cross-drilling) This trick assumes you have the slitting saw in a vertical mill, the bar is horizontal, and the slitting saw teeth are straight (i.e.. not staggered like a wood saw blade). Adjust the position of the bar and saw so that, by eye, the blade is just about touching the fattest part of the bar. Interpose a vertical 6" steel rule between the bar and the saw and move the table to very gently pinch the rule. Unless you were lucky and set the saw exactly on the fattest part, the rule will no longer be vertical. Adjust the hight of the saw until the rule is truly vertical - you will be amazed at how accurately the blade is then at centre hight. |
I have to make up about 14 such plugs.
(Although a nagging voice inside suggests that I should also consider the "Binding Post" approach together with spade terminals) "jtaylor" wrote in message ... "Airy R.Bean" wrote in message ... Thanks for your ideas - it's always the way that there's more though and effort needed to be put in to make the jig than to make the device in which you're interested! "jtaylor" wrote in message ... I had to thread the hole through my block, but you don't need that. If you wanted to get fancy you could make a shouldered sleeve with your setscrew holding the stock, drill a hole in the shoulder, and two holes in the block for a pin to set your 90 degree cuts. If you're making more than half a dozen it'd be worth it. |
Damn! I knew I should have purchased that digital
height gauge at the club sale, especially as it was only £10! The only difficulty otherwise with what you suggest is the tendency of slitting saws to bend under the slightest lateral force, but thanks anyway. "Andrew Mawson" wrote in message ... "Airy R.Bean" wrote in message ... Is there a "kink" for setting up a slitting saw to saw through round bar stock along the axis, so that the slot is exactly across a diameter? (I presume this to be a similar problem to setting up accurately for cross-drilling) This is actually a Ham Radio application; I wish to make up some very large banana-type plugs from the 1/4" round bar stock that I have in small quantities. For this, I will need to saw two diameters in a cross shape, and then splay out the leaves slightly to make a springy and rubbing contact. Assuming you are using a vertical mill so that the slitting saw is horizontal, and the work is fixtured horizontal (vee block perhaps): a/ Measure height of top of stock with vernier height guage, subtract half the stock thickness, and add half the slitting saw thickness - set the height guage to the resultant figure. b/ Adjust quill of mill so top of slitting saw just touches the height guage and lock the quill. You now have the slitting saw bang on centre of the work. |
"Airy R.Bean" wrote in message ... Is there a "kink" for setting up a slitting saw to saw through round bar stock along the axis, so that the slot is exactly across a diameter? (I presume this to be a similar problem to setting up accurately for cross-drilling) The simplest way I know to locate a line on top of round stock is this: (BTW, you don't have to switch from vertical to horizontal modes to make it work.) Mount the stock parallel to the mill table, and dead-level, with the "working end" solidly in your mill vise, and enough overhang for the slitting saw to clear the vise when you're working on the _side_ of the rod. True up the work with your longitudinal travel, so it's _pretty_ good. A thou. is OK, you don't need it to tenths. With any-ol' side-cutting bit, slowly close in on the side of the work until the bit just kisses the metal. Then make a longitudinal cut for however far you want the slit to go. You've now marked a line and flat that is parallel to the axis of the rod, and perfectly centered on the horizontal diameter of the rod. Without removing the work from the vise, you can switch to your slitting saw, and true up the saw to the line you've just marked -- then cut. LLoyd |
"Airy R.Bean" wrote in message ... Is there a "kink" for setting up a slitting saw to saw through round bar stock along the axis, so that the slot is exactly across a diameter? (I presume this to be a similar problem to setting up accurately for cross-drilling) This is actually a Ham Radio application; I wish to make up some very large banana-type plugs from the 1/4" round bar stock that I have in small quantities. For this, I will need to saw two diameters in a cross shape, and then splay out the leaves slightly to make a springy and rubbing contact. Doesn't need to be "exactly" because it's the diameter that is more critical than the position of the slot - I suspect even as much as just less than the thickness of the slitting saw off centre would not be a problem. I made a connector (female as opposed to your male) for an old radio by slitting brass tube. Hacksaw and vice produced good enough accuracy for an excellent operational performance. Steve |
I made a connector (female as opposed to your male) for an old radio by
slitting brass tube. Hacksaw and vice produced good enough accuracy for an excellent operational performance. How about making a square fixture to hold the round part with two slits to guide the saw blade? I have found that a good fret/jewelers saw very handy for cutting small items. I find it very difficult to cut 1/8 drill rod with a hacksaw but easy with a fret saw. They cut faster than you expect. |
Lay the round bar stock in a Vee and put it under the saw so the saw just
touches the highest part of the rod. As long as the stock is round you'll have a tangent to the diameter and all you need to do is start slotting, half in two. There used to be lots of banana plugs for sale on eBay and hamfest, quicker, easier, and cheaper than DIY. -- 73 Hank WD5JFR "Airy R.Bean" wrote in message ... Is there a "kink" for setting up a slitting saw to saw through round bar stock along the axis, so that the slot is exactly across a diameter? (I presume this to be a similar problem to setting up accurately for cross-drilling) This is actually a Ham Radio application; I wish to make up some very large banana-type plugs from the 1/4" round bar stock that I have in small quantities. For this, I will need to saw two diameters in a cross shape, and then splay out the leaves slightly to make a springy and rubbing contact. |
On Thu, 13 Jan 2005 13:13:17 -0000, "Airy R.Bean"
wrote: Is there a "kink" for setting up a slitting saw to saw through round bar stock along the axis, so that the slot is exactly across a diameter? (I presume this to be a similar problem to setting up accurately for cross-drilling) This is actually a Ham Radio application; I wish to make up some very large banana-type plugs from the 1/4" round bar stock that I have in small quantities. For this, I will need to saw two diameters in a cross shape, and then splay out the leaves slightly to make a springy and rubbing contact. I usually use a 5C collet spin index, as http://www.use-enco.com/CGI/INSRIT?PMAKA=235-6011 This makes it easy to get the two cuts 90 deg apart. I set the height as Jim Rozen suggested. A hint there is to touch the slitting saw as close as possible to the center, where it is supported by the mandrel. That minimizes any flex in the saw when "touching" for zero. I have a dial indicator mounted on the quill of my mill, so I just lower the quill 1/2 dia + 1/2 saw thickness, lock it and cut. Once you have the height set, it's easy to rotate 90 deg for the other cut, then pop the piece out, reload another blank, and make the next one. Shouldn't take 20 minutes to make 14 of them, once set up. A set of holes and a tapered pin in the spin index makes it easy to hit any increment of 1 degree with accuracy sufficient for most purposes. Those spin indexes are also handy for making hex heads or wrench flats on round things, drilling cross holes at various angles, lots of uses. One of the better $29.95 I ever spent! |
Set it on center, set your depth of cut, set your speed and feed, cut. What
more do you want? "Airy R.Bean" wrote in message ... Is there a "kink" for setting up a slitting saw to saw through round bar stock along the axis, so that the slot is exactly across a diameter? (I presume this to be a similar problem to setting up accurately for cross-drilling) This is actually a Ham Radio application; I wish to make up some very large banana-type plugs from the 1/4" round bar stock that I have in small quantities. For this, I will need to saw two diameters in a cross shape, and then splay out the leaves slightly to make a springy and rubbing contact. |
That's the question, how do you set it on center?
-- 73 Hank WD5JFR "CW" wrote in message ... Set it on center, set your depth of cut, set your speed and feed, cut. What more do you want? "Airy R.Bean" wrote in message ... Is there a "kink" for setting up a slitting saw to saw through round bar stock along the axis, so that the slot is exactly across a diameter? (I presume this to be a similar problem to setting up accurately for cross-drilling) This is actually a Ham Radio application; I wish to make up some very large banana-type plugs from the 1/4" round bar stock that I have in small quantities. For this, I will need to saw two diameters in a cross shape, and then splay out the leaves slightly to make a springy and rubbing contact. |
On Fri, 14 Jan 2005 01:46:43 GMT, "Henry Kolesnik"
wrote: That's the question, how do you set it on center? Hi Hank, It seems it's not how, but how well. The how is trivial. The how well is more a matter of a stock of ¼ inch which is sacrificed to lumbering gross tools. Modern machines just make errors faster when it is obviously within the scope of simpler hand tools and jigs. More time has been expended in the sterile scribblings of what could be, in place of actually getting it done. 73's Richard Clark, KB7QHC |
That's a good idea - I must otherwise admit to being lazy when
it comes to the possibility of NOT doing things with a hand saw! "Charles A. Sherwood" wrote in message ... I made a connector (female as opposed to your male) for an old radio by slitting brass tube. Hacksaw and vice produced good enough accuracy for an excellent operational performance. How about making a square fixture to hold the round part with two slits to guide the saw blade? I have found that a good fret/jewelers saw very handy for cutting small items. I find it very difficult to cut 1/8 drill rod with a hacksaw but easy with a fret saw. They cut faster than you expect. |
The biggest off-the-shelf bananas that I have seen are
4mm. In any case, doing things for yourself is what differentiates the Radio Ham from the CBer! "Henry Kolesnik" wrote in message m... There used to be lots of banana plugs for sale on eBay and hamfest, quicker, easier, and cheaper than DIY. |
How do you propose to set it on "center"? (English speakers
spell that as, "centre"!). That is the nub of my enquiry. "CW" wrote in message ... Set it on center, set your depth of cut, set your speed and feed, cut. What more do you want? "Airy R.Bean" wrote in message ... Is there a "kink" for setting up a slitting saw to saw through round bar stock along the axis, so that the slot is exactly across a diameter? (I presume this to be a similar problem to setting up accurately for cross-drilling) This is actually a Ham Radio application; I wish to make up some very large banana-type plugs from the 1/4" round bar stock that I have in small quantities. For this, I will need to saw two diameters in a cross shape, and then splay out the leaves slightly to make a springy and rubbing contact. |
"Airy R.Bean" wrote in message ... How do you propose to set it on "center"? (English speakers spell that as, "centre"!). That is the nub of my enquiry. Well, if you have "stock", and it's a small thing of which you're making many, you get a method that allows both measured increments and a locking system. You do a test, and adjust, so that once it's good enough, you just shove the stock in and slice it. If it's a one-off that has much time/money/work already into it, you use the same arrangement but plan and measure as best you can first. |
Stupid boy.
"jtaylor" wrote in message ... "Airy R.Bean" wrote in message ... How do you propose to set it on "center"? (English speakers spell that as, "centre"!). That is the nub of my enquiry. Well, if you have "stock", and it's a small thing of which you're making many, you get a method that allows both measured increments and a locking system. You do a test, and adjust, so that once it's good enough, you just shove the stock in and slice it. If it's a one-off that has much time/money/work already into it, you use the same arrangement but plan and measure as best you can first. |
Airy R.Bean wrote:
The biggest off-the-shelf bananas that I have seen are 4mm. I've got some that are about 0.3 inches in diameter. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
On Thu, 13 Jan 2005 13:13:17 -0000, "Airy R.Bean"
wrote: Is there a "kink" for setting up a slitting saw to saw through round bar stock along the axis, so that the slot is exactly across a diameter? (I presume this to be a similar problem to setting up accurately for cross-drilling) This is actually a Ham Radio application; I wish to make up some very large banana-type plugs from the 1/4" round bar stock that I have in small quantities. For this, I will need to saw two diameters in a cross shape, and then splay out the leaves slightly to make a springy and rubbing contact. You might get a better result with less trouble by using tapered plugs rather than cross-cut pins. Get a #4 taper pin reamer to ream the "jacks", set up your lathe to cut the mating taper on the plugs. The nominal dia of the large end of a #4 taper pin is .250" The taper is .250" per foot. This is about 1.19 deg included angle, which would be a "self locking" taper providing very good contact if you got the taper right. You could also just buy taper pins, solder them to the ends of bits of shaft and copper-plate them. |
There are various methods. First, you have to specify what kind of equipment
you are using. You never did say. BTW, American speakers spell it center. We left England so we were free to do it a better way. "Airy R.Bean" wrote in message ... How do you propose to set it on "center"? (English speakers spell that as, "centre"!). That is the nub of my enquiry. "CW" wrote in message ... Set it on center, set your depth of cut, set your speed and feed, cut. What more do you want? "Airy R.Bean" wrote in message ... Is there a "kink" for setting up a slitting saw to saw through round bar stock along the axis, so that the slot is exactly across a diameter? (I presume this to be a similar problem to setting up accurately for cross-drilling) This is actually a Ham Radio application; I wish to make up some very large banana-type plugs from the 1/4" round bar stock that I have in small quantities. For this, I will need to saw two diameters in a cross shape, and then splay out the leaves slightly to make a springy and rubbing contact. |
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