Tapered gib

[chevdrgtrk]

Anyone know where I can find a tapered gib? I got my lathe from my father who rolled it over, took it appart, and never got it back together....I pretty much have half a clue as to the rest of the parts that he lost, but I cannot seem to find one anywhere. I measured it to be about 22" long......my other idea was to take the cross slide, chuck it up into my mill, and turn it into a straight gib with set screws to take up the slack, but then i run into the same problem.......where do I get the gib at?

[Runner4404spd]

what kind of lathe is it?

[chevdrgtrk]

It's a Howa Sangyo 1500 17X60.....the company sold out, and now it's Okuma, there used to be a lady in the parts department that started to get some prints from Japan for me, now she was replaced with someone else, and they aren't willing to help me at all.......I'm thinking that they would just prefer my machine to not run, and for me to buy a new one from them, if I did that, it wouldn't be from them, there support hasn't exactilly impressed me.

[handlewanker]

Hi, It is not a very difficult job to make up a jib strip if you have a reasonable ability with a milling machine.
If you look at the end of the crosslide you will see the shape of the tapered jib.
It is only a long strip of STEEL that happens to taper according to the taper in the crosslide.
The other bit is the STRIP lays over at an angle of about 60 degrees or so.
The last bit is to examine the front and back of the crosslide and if it is counterbored with a threaded holes in the middle, then you're laughing.
The jib has a small slot or cutaway at it's ends, that engages with a large headed screw adjuster, that pushes the jib in and out to set the tightness of the slide.
To make the jib, just get a piece of mild steel (steel will run on cast iron very well) and mill it to the taper of the jib, measured by checking the width of the gap at both ends of the crosslide when it is on the saddle of the lathe.
The large end of the jib will want to be about .030" thicker than the thickest part measured to allow for driving the jib into the slide.
The taper of the jib MUST equal the taper as measured over the length of the crosslide and to the largest and smallest gap.
If your vice is on the small side then the steel strip would have to be attached to a steel plate, by drilling a number of holes through the strip and tapping them, and screwing to a piece of steel plate with countersink head screws, NOT ALLEN HEADED CAP SCREWS, and this will be bolted down on the mill table.
Don't use Cap screws, as they are too hard, will play havoc with your milling cutter when you come to mill the strip.
The screws will come in from the bottom of the plate and are counter-sunk into it, to clear the table.
The steel plate is set up on packers on one end, to get the taper.
Alternatively a tilting table could be used but it would have to carry 22" of steel strip.
The steel strip would need tapping at about 4" intervals to hold it flat.
It doesn't matter if the screws come through the top surface of the strip, and will just hold oil like pockets when the jib is in the slide.
The next operation will be to redrill the "jig" plate to allow the steel strip to hang over the edge of the plate so as to allow the edges of the jib to be milled.
An adjustable angle plate would be handy here. I filed one, using a 14" coarse flat file instead of milling it, but that was years ago when I was more energetic.
The top and bottom edges are milled at an angle and CLEAR the top and bottom of the slot in the crosslide by at least .020", very important to CLEAR.
Once the top and bottom edges are milled the jib can be tried in the crosslide to check the taper, using marking blue to reveal the fit.
It will be a pound to a pinch of poop that one end will be a bit thicker than the other, so now we can either surface grind the required amount or hand scrape, depending on your machine availability, or expertise with a hand scraper.
If there is more than .010" difference then put it back on the plate and remill it.
If you carefully analyse the steps, you will see that it is a relatively simple excercise, but at first sight it is a mystery.
There may be adjusting screws at both ends of the crosslide, and this will dictate the adjusting method, one pushes and one locks.
If you would like a more detailed description I could write an essay and probably include a photo or sketch, but it really just requires a bit of logic.
I've made a number of tapered jibs and never had any trouble with either making or fitting them.
The hardest part is holding the length firmly and flat for milling.
After it is milled the strip will probably have a bow in it due to the stresses being relieved from one side.
I would carefully beat it with a copper hammer, laid FLAT on a steel block, untill it just starts to curve the opposite way, and take another skim.
A small curve doesn't really matter too much.
Ian.

[chevdrgtrk]

WOW that is pretty in depth Ian....my 2 main problems was that my vice was only a 6" and I didn't even think of making a jig plate, so that should be pretty easy, the other is getting the correct taper. I don't have, nor do I know anyone that has an adjustable angle plate......especially on capable of holding such a long piece.......just a little question.....since you have done this before, how much would you charge me to make one if I supplied all the dimensions? or I can draw it up for you if you would like. It uses the "push-lock" meathod of securing.