Any Simat 101 lathe users out there?

[RichardG]

I have a Simat 101 lathe which is a 70’s version of a flexispeed, full details here. Lathes.co.uk



it works but I cant get a good finish due to chatter, I end up running slowly, taking tiny cuts and keeping the tool very sharp but the finish is still disappointing, I.e. you can’t turn a smooth surface for say a simple bearing.

I wondered if there are any other users out there who have done any improvements or point me towards the lathe weak spots.?

 

[Jelly]

Are you turning EN3/EN3B? If so it will experience surface ripping unless you have the stars in perfect alignment, anoint the surface with cutting oil fragranced with myrh, and sacrifice 10mm socket to the workshop gods...

It's not actually that bad, but in practice it machines best with light cuts at high surface speeds, and still only gives a truly good finish under an oil-rich flood coolant.

I have found EN1A and EN8 machine far better than EN3B, and the alloy steels like EN19 (aka 4140) machine even better still.



The surface speed thing leads me to a second thought, do you use carbide tooling?

The recieved wisdom is that small lathes don't have the oomph to benefit from carbide, but I disagree entirely. I've found even on very little lathes insert tooling can give really good results because you can use a much higher surface speed, which tends to give better results.

Depending on power output the standard negative rake chipbreaker inserts ([x]CMT) can be a bit much for really small lathes, but the sharper inserts often sold for turning aluminium ([x]CGT) will usually perform reasonably well as finishing inserts.

 

[RichardG]

Thanks, for the reply, good to know that it’s not just me. I’m using HSS cutters only, not tried carbide, perhaps I will buy one. I‘ve no way of doing flood coolant, I just tend to give it a squirt of aerosol cutting fluid as I go along. I’m also a bit short of myrh at the moment!!

The steel is unknown as I was given a box of-off cuts when a friend was clearing out his garage but probably EN3. However, I did cut some silver steel last week and that was’t a lot cleaner. In the end I had to buy a piece the exact size and then just turn the spigot rather than turn the whole thing. See spigot below.



I‘ve also tightened up everything to the point where the lathe is a bit of a pain to use as everything is a bit too tight. I was thinking of replacing the plastic shims used with some brass, see here.


I was also tempted to replace the top slide with a solid block as it‘s only fastened on one side and seems a week point.


I was hoping someone else had been through a set of tweaks to confirm whats worth doing but perhaps I’ll have to suck it and see.

 

[clogs]

there are many things that will give a bad finish......perhaps somebody close by might look over the late and give a few pointers.....
is ther a model engineering club nearby, they will also help......https://www.model-engineer.co.uk
u can still get a bad finish on bigger better lathes as well.......

just to add, when poss buy ur'self a couple of chainsaw files...a few diff shapes, mine are from Bacho, Sweden....they are great for
de-burring (they are quite smoth files) and to polish tram lines.....I also use em for just finishing off shafting to gain a decent sliding bearing fit.....
because the chain saw chain is HSS, these files can handle anything u are likely to turn (not ally or copper etc)
mine just get a wipe down with a cloth when getting grubby and full of bits.....they still work when wet with suds.....
I keep one flat one on each lathe an mill...4....they are around £4.00 each

As for getting coolant on ur lathe.....
my early Myford....now long gone didnt have any coolant either.....
so first u need to make a catch tray, then a stand/frame that will take a gallon can etc above the lathe.....
u'll need a tap and a dripper hose, found on ebay for pence...the sort with lots of knuckles, stays where u put it....
the drip tray must have a welded plumbing nipple with a cap .....so once the tank is 1/2 empty drain the tray and put the suds back in the tank via a funnel with a filter......it worked for me for years......
Once my stock of soluble suds oil is gone all my machine will be cleaned and straight 46 Hydraulic oil will be used instead.....

 

[RichardG]

Thanks for the tips, I tried a file today and it works well