What indicators are needed for scraping?

Oh yes I'm halfway through Connelys book. Haven't seen Schlesinger or Burley yet! Will have to check into it.
The Assessment tools are what I'm after! :)

Thanks, Paul
Here's the link to a copy of Schlesinger's book on Machine Tool Inspection

http://www.hobby-machinist.com/threads/testing-machine-tools-burley-schleshinger.41803/

But don't get all hung up in all of the tight tolerance requirements for new machine tools. Even in rebuilding machines, it takes a great deal of time in scraping and precision instruments to accomplish. And I doubt most of us can recondition our worn out machines to this standard. It is something to shoot for when reconditioning critical components. We can get them darn close!

Ken
 
I was wondering if a half a tenth is what I needed.

I believe (hope) you're saying you're relieved you don't have to buy an indicator that reads to half a tenth (0.00005" or 50 millionths of an inch). Such things do exist, even mechanical indicators, but they aren't cheap for darn sure.

Ken was saying to get an indicator with divisions every 5 tenths (two divisions every thou). I strongly agree that such an indicator is ideal (though still pricey).

I agree with everything Ken and Mike suggested.

I know next to nothing about machine reconditioning, but would still recommend my route of spending a few weeks learning how to scrape cast iron parts flat, parallel, and square first, before trying any reconditioning. It's puzzling enough to understand why blue-ups sometimes seem to change at random even with simple rectangular parts. Until you can reliably step scrape a part parallel and square within a a couple tenths over, say six or ten inches, I wouldn't attempt anything too serious on your lathe.

Measuring how much scraping is required is an excellent (and non-destructive!) thing to try in the meantime, though. It's instructive to see how well your measurements repeat, and how much they might vary from day to day. This video shows something Richard King's dad invented, called the "king-way" tool for measuring machine tool ways.

I've had my eye on this indicator for a while: http://a.co/bWpLsNS even though I have both a 0.001" and 0.0001" Mitsutoyo DTI. My DTIs require you to flip a switch to read with the lever traveling in the other direction (i.e. one setting when pushing the lever, the other when pulling) -- I think the interrapid style indicators eliminate the switch.

The tenths indicator is so nervous and fiddly in use that it's annoying, but it is sometimes useful (for measuring the depth of individual scrape marks, for example).

A half-thou indicator seems like it would be ideal to me, though I don't own one. You could still interpolate between divisions to estimate to one or two tenths, but the needle wouldn't bounce around quite as much as an actual tenths indicator, making it much easier to use.

In addition to a mag base and adjustable arm, you'll definitely want a surface gage and snug to fit your DTI (those are relatively cheap).

Regards,
--
Rex
 
.......................
The tenths indicator is so nervous and fiddly in use that it's annoying, ..............
In addition to a mag base and adjustable arm, you'll definitely want a surface gage and snug to fit your DTI (those are relatively cheap).

Regards,
--
Rex
Rex, you think a tenths reading indicator is nervous and fiddly, which you are correct, try a 50 millionths reading indicator. You literally can't keep the needle from moving. The fine adjustments you find on a indicator setup are almost totally useless. And even the fine adjustments on height gages are hard to use with the more sensitive dial indicators. I hate to try a digital indicator on a stand with a fine adjustment. I have a old analytical electronic indicator that goes down to 50 millionths. The electronics smooth out the signal so the needle doesn't bounce around so bad.
 
I believe (hope) you're saying you're relieved you don't have to buy an indicator that reads to half a tenth (0.00005" or 50 millionths of an inch). Such things do exist, even mechanical indicators, but they aren't cheap for darn sure.

Ken was saying to get an indicator with divisions every 5 tenths (two divisions every thou). I strongly agree that such an indicator is ideal (though still pricey).

I agree with everything Ken and Mike suggested.

I know next to nothing about machine reconditioning, but would still recommend my route of spending a few weeks learning how to scrape cast iron parts flat, parallel, and square first, before trying any reconditioning. It's puzzling enough to understand why blue-ups sometimes seem to change at random even with simple rectangular parts. Until you can reliably step scrape a part parallel and square within a a couple tenths over, say six or ten inches, I wouldn't attempt anything too serious on your lathe.

Measuring how much scraping is required is an excellent (and non-destructive!) thing to try in the meantime, though. It's instructive to see how well your measurements repeat, and how much they might vary from day to day. This video shows something Richard King's dad invented, called the "king-way" tool for measuring machine tool ways.

I've had my eye on this indicator for a while: http://a.co/bWpLsNS even though I have both a 0.001" and 0.0001" Mitsutoyo DTI. My DTIs require you to flip a switch to read with the lever traveling in the other direction (i.e. one setting when pushing the lever, the other when pulling) -- I think the interrapid style indicators eliminate the switch.


In addition to a mag base and adjustable arm, you'll definitely want a surface gage and snug to fit your DTI (those are relatively cheap).

Regards,
--
Rex


OK so opinions on which models of .0005 dials I should choose from? Figure I have $150 to get a decent one and I have an adjustable arm noga knock off base to put it on.

The surface gage I'm totally up in the air on knowing what to get. They look really simple to me but I'm sure there are plenty of differences in qualities.

Are the dials usually just pin or lever? Or are there combinations? Where the tips can be changed?

Paul
 
Figure I have $150 to get a decent one and I have an adjustable arm noga knock off base to put it on.

Ooh. Nothing more fun than spending other people's money. ;-)

These should help:

Amazon
MSC

For your budget I'd go with the SPI from MSC myself.

Variables are the quality and jeweling, mounting options, lever arm options, face color, and travel distance.

You don't need much travel distance (0.015" is plenty).

Look for a used Starrett surface gage on ebay -- shouldn't cost you more than twenty bucks or so. Small ones are model 56 or 57, large ones model 257.
 
For your budget I'd go with the SPI from MSC myself.

FWIW, I just ordered one of those 0.03" travel, 0.0005" resolution DTIs from SPI for myself.

$65 was just too good a price to pass up.

I still want a good Interrapid, though.
--
Rex
 
Ooh. Nothing more fun than spending other people's money. ;-)

These should help:

Amazon
MSC

For your budget I'd go with the SPI from MSC myself.

Variables are the quality and jeweling, mounting options, lever arm options, face color, and travel distance.

You don't need much travel distance (0.015" is plenty).

Look for a used Starrett surface gage on ebay -- shouldn't cost you more than twenty bucks or so. Small ones are model 56 or 57, large ones model 257.

I'm ordering one of the SPIs from MSC. Those surface gages are more than $20.00 how much is the max to pay? Looks like new they are over $200?
Paul
 
Back
Top