Thread: Precision Test Bar Runout

Brendan, If it's actually on the ground taper shank and it's a high spot then it would be affecting runout. You don't want to void your warranty by damaging the taper but you may need to grind it off in the worse case. Have you poked it with a scriber to see how hard it is? Contact Chronos and see what they say. This is one of the down sides of buying from OS, not easy to return faulty goods.

If this Black mark is on the tapered section and is measureing larger than the given size of what the small end of the taper should be,then yes it is probably effecting the reading.

Have you tried scraping it off?

.06 seems a bit much even for an old/older lathe.

Maybe your spindle taper is damaged slightly.

Is the reading you get the same at the Chuck the same as the reading at the Tailstock?

I havent tried anything except for a rag and solvents as I was paranoid about scratching up the taper...but I do agree...the black stuff has got to go.

At the chuck end I get less runout, just over .02 TIR

Should I try gently scraping with a razor blade or something?

Re the lathes taper, there was some damage at the large end. With the chuck off I could quite clearly see a lip there that shouldnt be. Initially, I had TIR of .5mm (thats not a typo)...so I cleaned up this lip very gently and got the TIR readings I reported in my original post.

I would try and remove it with a razor or a ground hacksaw blade.

Hi Brendan,

That precision test bar turning up like that would be a huge disappointment! I would email them in the first instance to see what they do. I have bought several things from them and I have found them to be OK to deal with.

Failing that, then look at mechanical removal of the offending black stuff. A scraper seems to be the agreed method. Perhaps get 90% off with a scraper and then try some 1200 Wet & Dry. Testing the fit as you go with some bearing blue?

Good luck!


Simon

OK, I went home and scraped it and got some off but there is plenty still there. Upon closer inspection it looks more sinister than I first thought....I believe that it is a repair that wasnt finished...I dont know how these things are made but to me it looks like it was a casting defect that has been filled, which I assume was then meant to be re ground but the grinding never happened. i'll see if I can get a pic with my womans SLR camera tonight to post up here to see if you agree. I will obviously have to get in touch with the seller.

I am experiencing the real negatives of internet purchases at the moment, I have three projects which have ground to a halt for over a month due to waiting for tools from overseas. This one (setting up the lathe properly) is something I have wanted to do for ages and now im going to have to wait another god knows how long until I can finish it.

Yea great. I have a nervous wait for my overseas purchase......

Thanks for the confidence booster Brendan!

Ha ha, you'll be right. I have purchased dozens and dozens of things from overseas and this is the first new product thats had a fault. The slow postage is an issue thats plaguing us all at the moment.

I also recently bought a dud second hand micrometer thats giving me grief, but i'll post about it seperately.

I just got a piloted tap holder from CDCO and it holds the tap at a 20degree angle to the hole. Now this really defeats the purpose of the device. Made in India and I must say I've never had any joy with Indian tools , I also have an 88 degree angle plate from India that I bough many years ago.

Originally Posted by 19brendan81

Ha ha, you'll be right. I have purchased dozens and dozens of things from overseas and this is the first new product thats had a fault. The slow postage is an issue thats plaguing us all at the moment.

I also recently bought a dud second hand micrometer thats giving me grief, but i'll post about it seperately.

Originally Posted by Swarfmaker1

I also have an 88 degree angle plate from India that I bough many years ago.

Might come in handy one day, LOL
I buy Indian tools from my bloke at the markets all the time, but I can check them over before buying them. I noticed with the tilting vice I bought the lock clamped onto the dovetail, the new one he put out the next week has a screw going strait onto the dovetail,

Brendan
Any chance of a picture?

Dave

Yeah i'll put a pic up...I need to take one to show the seller anyhow.

P.S that 88 degree angle plate sounds hilarious.

P.S that 88 degree angle plate sounds hilarious.

Only if it is EXACTLY 88 degrees.....

Originally Posted by 19brendan81

OK, I went home and scraped it and got some off but there is plenty still there. Upon closer inspection it looks more sinister than I first thought....I believe that it is a repair that wasnt finished...I dont know how these things are made but to me it looks like it was a casting defect that has been filled, which I assume was then meant to be re ground but the grinding never happened. i'll see if I can get a pic with my womans SLR camera tonight to post up here to see if you agree. I will obviously have to get in touch with the seller.

I am experiencing the real negatives of internet purchases at the moment, I have three projects which have ground to a halt for over a month due to waiting for tools from overseas. This one (setting up the lathe properly) is something I have wanted to do for ages and now im going to have to wait another god knows how long until I can finish it.

Brendan, personally I'd be a bit reluctant to use any form of removal that would remove material off the taper. If it's a type of plastic, have you tried acetone? If you don't have any handy, see your better half and ask to, errr "take a closer look" at her nail polish remover as that's just overpriced acetone.

More the point however is, what is it you're doing to your lathe that requires a test bar to "set it up properly"? While you can do it that way if you wish, there are other ways to set up a lathe that, while different, will get you to the same (well actually better) end point, and require nothing more than some scrap steel bars.

Pete

Its definately not plastic, its metallic. the black stuff seems carbonic, and underneath it looks like a defect has been filled (welded) up..poorly mind you. the guys at chronos were very helpful and said they would send me a new one out.