Member postings for Sandgrounder

I have old releases of Autocad and Inventor bought new in 2004 on a XP PC which I now rarely switch on, I use Draftsight all of the time on my Linux PC and found the transition from Autocad to Draftsight very easy,

John

An 'm5 fitting pin' would be a bar machined to suit the internal diameter of the oilite bush with British Standard 'm5' tolerance, which according to the website below would for say a 16mm dia bore bush be 16.015 / 16.007, there would also be a shoulder on the bar to press the bush in, this would ensure the the bush ended up with the correct internal diameter, the pin would if used for hand fitting also help to keep the bush in line with the hole.

http://uk.misumi-ec.com/pdf/press/us_12e_pr1263.pdf

but if your replacing needle rollers neither the existing shaft or housing may have the correct tolerances suit a standard oilite bush.

I would think that the 'after machining' refers to either the length or the non running diameter, as Swarf Maker said machining of the running surface will smear the surface and close the pores.

Edited By Sandgrounder on 19/07/2017 19:52:59

Swarf Maker is absolutely correct with his advice on Oilite Bushes, the fitting guide in the link below says that a 'm5 fitting pin' should be used on assembly to give the correct bore.

https://www.ondrives.com/data/pdf/bearings/bushings/oilites-tech.pdf

I've just been reading a safety fact sheet on Sodium Hydroxide and the advice is

"Never add water to a corrosive. Always add corrosives slowly to COLD water."

so it's safest to assume it applies to all, acids and alkalis.

John

Not too much though, the majority of bearing failures are down to having too much grease in them.

John

As Hopper has suggested, does it need to be cast iron? Reading Joe's other post the cracked dovetail is on the vertical slide, it's not the reciprocating ram, I'd use mild steel. Aren't a lot of these machine parts made of cast iron because you can easily & cheaply produce complicated castings which will just need a few faces cleaning up rather than it's low friction properties?

John

When I worked at Mullard Magnetic Components in the 60's where they made besides other materials, 'steel' magnets, you could get a round bar magnet say 3/4" dia x 4" long hold it in your palm and break it in two with a hammer without hurting yourself it was so brittle, just like Seaside Rock, when tapped holes were required the magnets would be cast with a plain hole to suit a threaded insert.

I used the description 'steel' only because they looked like steel, their composition was very different.

John

Just had a look on the RDG website, they have a Myford parting toll holder with a stepped bottom face, looks the same as mine.

https://www.rdgtools.co.uk/acatalog/SPARE-PARTING-HOLDER-FOR-QUICK-CHANGE----MYFORD-SIZE---X1-608550.html

Worthwhile checking with them to make sure it will fit your model before buying.

John

Following my post above re' the youtube video, I've just been to check mine, I normally use a rear tool post for parting off but I also have a 1/2" x 3/32" blade in a quick change holder, of the 12 holders I have 11 have flat bottom faces but the 12th which is the parting tool holder is machined as in the youtube video, this with the 1/2" parting tool allows me to adjust it from about 1/4" below centre to 1/16" above.

I bought it new but I'm sorry but I can't remember where from, probably either RDG or Chronos.

John

Edited By Sandgrounder on 10/06/2017 10:49:31

Others have had similar problems, this guy found his quick change tool holder bottoming on the top slide when using 1/2" tools, is this similar to your problem?

https://www.youtube.com/watch?v=8IzKCXwjjsM

John

At least with all these standards they are in English, the Japanese have to contend with "1/4" Whitworth" in their camera manufacturing industry.

John

I worked as a Draughtsman both before and after metrication and the latter was a Godsend, I found working with fractions was a nightmare especially on some of the American drawings we had to use, to find a particular length might require adding four or more dimensions such as 1-19/64" , 11/16", 3-17/32", 2.183" etc together and this was pre-calculator days.

John

Thanks for that advice, I'll leave it alone.

John

Had a look this morning and there's not much to see unless the whole thing is taken apart, I'll just have to assume that it was there and has been broken off.

John

That's interesting, I'll have a closer look at mine tomorrow,

John

My S7 Mk1 lever drops to a vertical position when the tailstock is unlocked.

John

And if you have a bolt with a damaged thread at the beginning you can slide the dies past it and work backwards.

John

The same for me, a good purchase.

There does sound if there is something wrong, as with John I built the Jerry Rollets design and find the speed for boring fine, and like Ian the belt never slips but the overload switches it off if I push it too far.

John

Sorry, I'd forgotten about that mod, I made the hole and fitted a cover and spacer over it.

John

Edited By Sandgrounder on 13/04/2017 10:27:58