Member postings for Men Ifr

Hi all, bit of an old thread but I was also dissappointed with the draper / magnetic style and started making custom fit vice jaws I intend to make sets for all record vices once I get all the dimensions (jaw height is what I need). I can make a set up if you are interested and am looking for people who could measure the jaw height and provide photos once fitted.

I would like to know what this is (above)

Spotted some interesting tooling in a watchmakers shop in Pewsey while out for a walk

For any-one else reading this here's another vote for this type using a bench grinder

I set it up to the side of a 80grit (fine) wheel. If you don't already have a bench grinder you could buy a bench grinder plus this type of sharpener for the price of the dedicated sharpeners and I get perfect results every time though smaller than 3mm gets a bit difficult. For small bits <3mm I buy branded Sherwood or similar split point stub drills as for starting holes and the difficult job of driling small holes they are far superior to cheap bits and only requiring the small sizes quite cheap.

There is no skill involved really, what is also useful is to cut a set of old drill bits with an angle grinder very short then re-sharpen as stub bits.

Just to update people how I'm getting on with this:

As per my other thread the 1st lathe that arrived has pitting in the ways. Chester replaced that with a 2nd lathe and the ways all look good. Unforutunately this 2nd lathe is imperial - I use metric . Due to the difficulty of moving the lathe - it took 3 hours of faffing around with a engine hoist I agreed with Chester it is easier for them to send some metric leadscrews and dials and I will retro fit them to the machine.

The 1st lathe had problems the lever would not release the half nuts and this lathe has problems the 1/2 nuts were catching on the leadscrew, this seems to be traced back to a screw missing which holds the lever on, the lever moved out a bit, the ballbearing for the indent has fell out so the lever would wander down when turning. I've resolved that now but needed to strip the apron down.

At a quick glance the 3 jaw chuck appears quite inaccurate but I will measure the run out a bit later.

I measured the alignment of the headstock to the bed by turning a piece of bar and its was out around 0.16mm over 4". The headstock can be repositioned as it is just bolted to the bed so I am in the process of doing that. It will be intesteting to see how close I can get it I'm hoping for 0.01mm over the 4 inches so we'll see. - If anyone has measured/adjusted theirs what did you get?

I'm also thinking I should check the up/down alignment of the headstock, I could do this by bolting a vice to the cross slide and machining the bar from the underneath then measuring taper as normal. I feel like I should at least check this as taking anything for granted with these Chinese machines I think is a mistake.

So far I've machined the backplate for the 4 jaw chuck, unfortunately have mads the collar ~0.2mm too small, I went back and checked my measurements what had happened was I measured the internal bore of the chuck with a digital caliper but having pushed the internal jaws in they met the (not visible to naked eye) taper at the end so gave a smaller reading than true.

I've obviously also been machining the bar for the taper measurements on the headstock and this works nice, the machine can be run at high speed without loosing power though could do with a finer cross feed so will look what I can do with the gears (gearbox is already at position 1)

As a general comment I have also bought a large/240kg milling machine from SPG tools and I appreciate it is bigger and twice the price of the lathe but the appearance, operation, build quality and attention to detail on the milling machine is far far superior to the lathe.

Anyway I'm happy to be turning metal but do wonder if i would have been batter off with a Myford.

That's useful though may be good to know if that's for HSS or carbide tools and there are no feeds.

I found this very useful diagram from cnccookboook

So the surface finish would seem to be limited by a feed so slow that the tool rubs not cuts and spindle speed limited by tool temp

What's interesting is I've turned parts with much higher spindle speed than the the table from the 1st link with no problems - if that is a table for HSS tools should it be multiplied by 4 for carbide (even cheap carbide) tools? Is there a limit surface speed for aluminium because it melts?

I've took feed rates below

Which gives 0.5 to 0.05mm/rev in metric

Edited By Men Ifr on 12/12/2018 12:59:32

Well thanks for the replies, I'll see what Chester say tomorrow. I'll have a look at the arc website to see what they have got.

So after turning down a nice Colchester as it was too big for me I bought a Chester 920 lathe however I'm not too happy with it at the moment - Do I persist trying to sort it or send it back?

Probably the biggest thing I can't fix really are the bed was not cast properly - the rough area is upto 0.2mm deep. Will it make much/any difference though.. I don't know. I've ran the slide up and down with dial against a reference block and that seems good however that's with no load .

There is not much contact between the slide and bed even where the bed is not pitted but I think that is normal for a Chinese machine and can be improved via scraping/lapping.

Another view of the ways

Plenty of grit in the gearbox - but it does have a 9sp gearbox which I like!

More grit/casting sand

Other issues - The half nuts are stuck open

Grit in most ways and between top/cross slide

leadscrew is slightly bent maybe 2-3mm in the middle

Some surface rust, I don't think critical but needs cleaning/oiling

Safety switch for the chuck cover does not allow cover to be opened.

So it's not great - I know it would not be.. but was not expecting it to be this bad. I'll email Chester and see what the say, maybe I'm unlucky and they can swap for a good one.. who knows!

Is any special method(s) required to remove grit after lapping?

After lapping the column on my small mill it was cleaned by rubbing with paper tissues until they came out clean then applying isopropyl alcohol and re-rubbing.

I now *think* the oil on the Z column is blacker than it should be which I wonder if that is an indication of either cast iron grit or lapping grit still present?

I wonder if post lapping rubbing over dry with a very fine wire brush maybe brass or something maybe better at dislodging any remaining small particles or is there a standard way to do this?

Oh dear.

I went to look at the Colchester the seller was a very nice chap but I think reality set in that it's too big for what I need right now and I didn't want the hassle of installing it in my garage for it to (potentially) sit there for a long time with little use, or regular use for little parts.

He had a huge amount of interest in it so was happy to sell it to some-one else and I've bought this from Chester hobby store:

https://shop.chesterhobbystore.com/collections/lathes/products/920-lathe

It seemed like a good price for a new 9 x20 lathe and has a 9sp gearbox which I like a lot. I need to add a tacho (already bought for £10) and work out a variable speed without loosing torque. When I rang I was told it also comes with 4 jaw chuck and steadies definitely a bonus as my first job will require a fixed steady.

It arrives Tuesday, so looking forward to using it next week!

I'm not sure how well this link will work but I've bough the Colchester Student advertised at £835, price seemed good, he bought it from a college so no industrial use, he's very local and works at my company so I can trust him.

https://www.facebook.com/search/marketplace/?q=colchester%20student&epa=SERP_TAB

I've said I will buy it (with out looking at it) and will goto look at it tonight to work out how to move it. I'm sure if it's in awful condition I could back-out but as he's a professional engineer I'm confident it will be in good nick.

It also comes with a home made rotary inverter which needs a bit of repair but if I can get an electronic inverter for not too much cash I think I'll use that but I need to find out if I will loose power/speed that way. Also I don't know if the original motor is 1.5 or 3hp..

Now I need to work out how to move it, he had offered the use of a heavy duty trailer.. but I'm reading some horror stories of people moving lathes now...

No accessories other than 3 jaw but will have to work that out later.