AX block actual wall thickness

[rgh0]

Just looking at an old Ford block drawing and there is a reference to two grades of cast iron - A or AX. This confirms the comment above that the AX designation on the blocks referred to a cast iron grade. The block drawing was the same for both dimensionally.

I think this says that the AX block was no thicker than other blocks but potentially stronger and maybe heavier with a different grade of cast iron.

Weight is going to vary between blocks due to the random variation in wall thickness of the castings and unless you have 10 or so AX blocks to measure versus 10 or so other blocks its hard to say that they are systemtically heavier

[Andy8421]

under A$1000 will get you a very accurate gauge USA made gauge, less for a little less accurate and less reliable Chinese one. You need to calibrate it on the individual casting's sonic velocity being tested by measuring the thickness on a section you can check the thickness with a micrometre as the calibrations changes with every block.

cheers
Rohan

Rohan,

I want to measure the thickness of the walls of my block. I am big fan of trying to do things myself, and generally buy the tool to do the job, and then tuck it away for use later (that's how I ended up with a Bridgeport mill.......).

There are 'cheap-ass' ultrasonic gauges on eBay of far eastern manufacture:

https://www.ebay.co.uk/itm/354647688147?hash=item5292a643d3:g:THIAAOSwkpBkECZy&amdata=enc%3AAQAIAAAA0M0YhMljrh9viXpvElG9wiSbc8zGbw9Yo8RYd3HuGRvEjZEi62bbL29utrGNI1r36oQ7j4UbK13m1Tmu0r%2FKQ3%2B5EA3ZEvLsyQ15BvJpFeBSxTWYGkwP%2Fjya22wH0iWhggjX3YmckOoP3GE%2BKt3qiP1iE7ScW%2B005%2FSezW6z39TD4J09tVQ5kWW2Hs98gl%2Byo1lI5KNrdB4J4l8NKfod2TgVEJYC3UaMBo69hPXZWHKGwu4NCbpHTWHB6dZH6P8s25oU4kaPdj8s2BI%2FeEdGYJM%3D%7Ctkp%3ABk9SR4SG8JT4YQ

As I understand it, I can calibrate the gauge on a bit of the casting that I can get to and measure, so absolute accuracy isn't important, just relative accuracy. Earlier posts of yours mention aiming for 3mm as the minimum cylinder wall thickness post boring.

Am I wasting my time with the cheapo gauge, or will it be good enough to give me a ball-park figure?

As ever, thanks for your wisdom,

Andy.

[rgh0]

I got the Dakota Ultrasonics PR-8 with two probes suited for measuring internal curved surfaces.
i.e.
1/2 in dia with 1.5 inch head radius 5 Mhz for cast iron cylinder walls
1/4 in dia with 0.6 inch head radius 10 Mhz for cost aluminium head ports with a 9 inch wand to reach down the ports.

The cost was around US$ 1000 at the time many years ago including the two probes. I thought this was a bargain as i had been using at my work $20k machines which did much the same thing

It has been superceded by the PR-9 which lists for US$1325 on their web site and a second probe if you wanted it is around an extra US$300.

It has proved to be very reliable over many years. i purchased this before the cheap chinese ultrasonic devices were available.

If i was buying one again today i would probably try a cheap chinese one like you showed given the price difference. When buying these sorts of electronic instruments out of China it is worthwhile carefully researching the market and checking the actual manufacturers web site. As the same instrument will be sold under multiple names at varying prices. i also try to buy a midrange chinese instrument rather than the absolute cheapest.

cheers
Rohan