Member postings for lfoggy

You probably already know this but the coefficient of thermal expansion of acetal is quite high so even small changes in temperature can cause significant dimensional change. This has caused me problems in the past using Delrin as a piston material.

Interesting comments re Indian made tools. I'm not sure we can legitimately generalise about the manufacturing quality of an entire nation but I avoid Indian made tools as well. Purchased a milling vice made in India a few years ago that was comically bad. Once bitten etc.....

I am thinking of buying a BS-0 dividing head and have been looking at what is available. Sadly original used Brown & Sharpe examples seem unobtainable so have been looking at the currently manufactured copies. They are all of course made in the far east and all look pretty much identical in the pictures on various websites and eBay. The unbranded ones seem improbably cheap costing as little as £300 including a three jaw chuck. The Vertex branded versions look indistinguishable but cost a bit more at around £450 (from Rotagrip for example). My question is are they actually all identical (and maybe manufactured in the same factory) or are the Vertex versions better in some way? Ideally I want a unit that will work well straight 'out of the box' without requiring fettling like so many inexpensive tools do. I've got few Vertex products and they do seem fairly consistent and reasonably well made so am inclined to pay the extra but would be interested in hearing from anyone who has experience with any of these.

I had one of these hacksaws and changed the belt and pulleys to 'V' belt. Much better than the original flat belt which was forever slipping or falling off.

I've been using the edge finder below for many years and have always had consistent results to within 0.02 - 0.04mm. Recently the edge finder started behaving erratically with really inconsistent and erroneous readings. Much head scratching ensued and I could't figure out why. Then i noticed it was working fine on non-ferrous metals and the penny dropped. The probe of the edge finder had become very slighly magnetised. Not enough to notice it sticking to anything but enough to give the aberrant reading and enough to pick up iron filings. Quick demagnetisation and its all back to normal. I'm sure that I am not the first to have this issue but I had never come across this before so thought it worth sharing...

Thanks for all useful replies. Didn't know about h8 and H8 but it makes sense.

My measurements were all taken with an ordinary Mitutoyo digital micrometer. This seems to give remarkably consistent results to within a few microns. This is the micrometer measuring a setting standard at 20C. With care it measures to within 0.002mm of 25mm fairly consistently.

The part is required to help a friend restore an old Reichert microtome. It is in fact just a replacement for a damaged shaft so nothing special really but it does need to match the original which seems to be a few microns under 10mm. I fear that my box of random bits of silver steel may not be the best place to look....

My current project requires a length of accurately ground 10mm diametre steel bar and ideally I want a 12cm long piece, bang on 10mm, straight and parallel. I've got 6 lengths of 10mm silver steel from various sources and have been surprised at how variable they are in size when measured accurately, ranging from 9.970mm to 9.998mm. The 9.998 piece is suitable but its not parallel and tapers from 9.998 at one end to 9.990 at the other over 30cm. This is still OK for my needs but I wonder what the typical tolerances on ground silver steel bar are.

Is it possible to buy more accurate and consistent ground steel bar?

I got the test information below with my Chester 836VS mill. Turned out to be fairly accurate when I checked the measurements.

Spelling quite comical though....

I inherited a Myford ML7 with a full range of tooling when I was 16. There was nobody in my family who had a clue about lathes so it was a steep learning curve !.Basically I learnt by trial and error with error being the operative word. That was 40 years ago. I still have the machine, which I now know was one of the earliest ML7s made by Myford.

I suggest directing your nephew to a few simple projects and letting him get on wth it. Teenagers won't listen to you anyway ! I have a Stuart 10V on my desk as I type that I made when I was 17....

Lukas

I've just acquired a 'job lot' of new milling cutters consisting of mainly 6-20mm slot and end mills. Included however were 7 new Dormer end mills with 25mm and 1" threaded shanks. I have a mill with an R8 taper and usually use R8 collets to hold cutters. Max size for these is 20mm I believe. These new cutters are too good to waste so I need to find a way of holding them. Looks like I may need to buy an ER40 collet chuck and holder but are there any other options?

Regards

Hi everyone, I've got a home workshop in Birmingham and have built all mannner of things over the years. Recent projects have been a Stuart Major beam engine and an English regulator clock. Currently building a model Harley Davidson V-twin IC engine. I've got a Myford 254 purchased new in 1997 and a recently acquired Chester 830VS milling machine plus the usual collection of other tools. Not had much contact with other model engineers over the years so would be good to find out what is happening locally.....