Member postings for Nige

Thanks Neil. Yes I took pictures of the cross slide backlash adjusters, two small cap screws, by putting a mirror at an angle behind the lathe so I could see what was going on. They are easier to get at if the cross slide is wound almost right across. I realised it wasn't wise to let it go right across as at some point the lead screw is no longer in the whole length of the split nut and no amount of tightening the adjustment screws will make a difference to the backlash UNTIL of course you try and wind the cross slide back again!!

If I wind the cross slide out until the lead screw comes out of the split nut should the cross slide just slide off the end ? and if it does is it just a question of reversing the process to put it back assuming you haven't dropped the gib strip 😊

The SC4 lathe 'manual' has a chart giving the threads that can be cut with which gears. The imperial threads are given as 1"/n which I take to mean that the entry for 12 is 1/12 or 12 tpi, does that seem reasonable, if so the finest imperial thread it gives gear settings for is 24 tpi.

The metric threads are shown as just mm so I take it that 0.25 is the pitch which if my sums are correct gives a thread of about 102 tpi !!! While the coarsest metric thread is 3 mm or about 8.5 tpi. That seems a hell of a range in metric threads while imperial is given as 8 to 24 tpi! Am I missing something please?

OK, been out to the lathe and:

Andrew: Thank you, I now understand the need to disengage the saddle feed handle

Jason: Thank you, Yes to the end float!! In my inexperience I was assuming the whole problem was backlash. The Nyloc nut that holds the cross slide handle on had only been tightened enough to locate the handle, when I took another turn or two on it with a 14 mm spanner the end float disappeared.

Today I have learned that getting a good 'feel' for the cross slide feed is about getting a balance between backlash and end float. Thank you guys

Nige

I would like to know about backlash in the cross slide feed please. It seems a bit excessive at 0.8 mm which is 40 divisions on the dial and I wonder if that has anything to do with the fact that it can be power fed. I will take a look at the exploded drawing and see if there is easy access to the nut and adjustment screws at the far end of the slide.

Another interesting feature, and disturbing the first time it happen, is that the saddle feed hand wheel will pull outward almost 1 cm which disengages its ability to move the saddle and exposes a gear which I presume engages on a rack to move the saddle. Is it supposed to do this and if so what is the use of such a feature ?

Many thanks, Nige

Finding that I needed a way to set a block at 45 degrees in the milling vice I had to make a 45 degree angle plate from an off cut piece of aluminium angle which I clamped in a V Block so I could machine flats on the feet of the V. Had to get creative in clamping the angle piece in the V Block but quite pleased with the method I came up with.

I wanted to change the gears in the SC4 to cut 12 tpi threads. I knew which gears I needed to fit so uncovered the gearbox. Having taken a good look I decided to change the A gear first, only because it was at the top and closest, My first problem/worry was that the socket headed screw that holds the gear in is quite small and the fit of the hex wrench was not very good, in fact what I consider to be my 'quality' hex wrench was a sloppy fit. The screw was so tight It got to the point that I was afraid I was going to round off the socket. I gave the screw a few lite taps with a small soft hammer to try and persuade it to loosen up. It did eventually give but not before I saw a lot of twist in the shaft of the wrench.

The 'A' gear is mounted, keyed, to shaft permanently fitted to the 42 tooth gear behind it. Getting the gear off for the first time was a matter of putting two thin screwdrivers between the two gears and gently levering them apart. I suspect the fit will 'loosen up a bit' with repeated changes.

The B&C gears are keyed together on a stub that is fixed to the adjustable arm that rotates around the D gear on the lead screw centre. The adjustment arm is held by a socket screw 'pinch bolt' which is released to drop the B&C gears out of engagement with the A and the D gears. Be aware that B&C gear stub screws into a T piece that runs in the back of the adjustment arm and at the outer (gear) end there is a nut and spacer that goes onto a thread over a square end. Again the gears were a tight fit on the keyed stub but easier to deal with by placing them on a part open vise and tapping the stub out with a copper drift and a brass hammer. Again I suspect they will loosen up over time.

Something I have been meaning to do for ages: replace a knackered and rusty 5 foot twin fluorescent fitting with an LED Batten fitting. On the spur of the moment I diverted into Screwfix on my way home and asked the guy for an LED 5 foot twin batten fitting. He came back with a 60w 5600 lumen item priced at around 35 quid.

It is very light in weight being mostly polycarbonate and the enclosure is rated IP 66. It was a doddle to fit only needing two screws to fit it to a joist in the workshop and wiring couldn't be simpler. The units can be chained together electrically so installing the next two, a couple of 4 foot versions over the lathe and the mill will be simple.

When I switched it on I was very pleasantly surprised by the quality of the light and the brightness of it. On looking up the equivalent of 5600 lumens I was pleased to find that it is in excess of 200W equivalent in tungsten incandescent lamps. The thing has a 3 year guarantee.

**LINK**

I would post the usual "I have no connection......" disclaimer except that I work for B&Q who are part of the Kingfisher Group that also owns Screwfix 😊

Thank you everybody for the advice and great info on a variety of pin options. Jason's post says all about what I am making and thanks Jason for the advice. I think I will pin it as you suggest if just for the engineering practice

Nige

This is the block I bored and the blank end arbor in position. I am going to loctite the arbor and then pin it as suggested. The block is 44 mm square. I was considering using a roll pin is that a good solution

Mark: Thank you, just what I wanted to know about the Loctite.

Hopper: no, I haven't checked the carbide tool tip though I will now. I understand what you are saying about rubbing and rough cutting. I'm using the carbide tools as I have them though I also have a load of HSS. I think I was beginning to think I just wouldn't need to keep 'sprucing up' a carbide tip as I might an HSS one and forgot that carbide can be quite delicate. I still have the piece mounted and will take an HSS tool with a slightly rounded nose to it.

NDY: the hole is for a blank end arbor on a morse taper. The end of the block you can't see has a 90 degree V slot milled across it to locate round bar while it is cross drilled. Drilling and pinning might not be necessary as I don't think there will be much torque on the block in normal use

Jason: Depth of cut was minimal I think as it was being applied with the saddle feed handle and done by 'feel' and I was being cautious as it was an interrupted cut. In hindsight maybe I should have used the compound slide for finer control of the feed. I was using one of the carbide tools that I bought with the lathe and hadn't thought about whether it might be suitable or not 😳

I have come to realise in just a couple of days machining that I need a much better idea of cutting speeds ! I might sit down and make myself a chart with a basic guide to cutter or drill diameter agains material surface speed for the material I am useing then stick it on the workshop wall !

Andrew: Thanks for that link, useful stuff. I have no idea of the grade though I bought it from a local professional supplier just as BMS from their short ends rack. Looking forward to tea and turning 😊

Vic: the bored hole in that bar I am particularly pleased with. It is the first 'boring' job I have ever done and I had to grind and modify an old HSS tool to do it. I ground it to cut both along the axis of the bed to open the hole up and to use as a facing tool in the bottom of that hole; very pleased with the whole process really as I applied quite a lot of knowledge I have been piecing together recently and tried different tools and techniques. Also happy that the blank arbor I bored the hole for is a non sloppy sliding fit, difference in diameters is .03mm as near as I can measure. Hoping somebody will tell me which 'sticky' engineering product will take up that bit of clearance and hold the arbor tight in that hole 😊 All in all a happy learning experience so far 😀

Thanks guys. The material is bright mild steel and I was brushing on coolant as well. The cut was taken with the power feed on the cross slide. No need to tread carefully Andrew, as somebody with extremely limited experience I'm happy to take well intentioned criticism The central part IS ridged which is what has thrown me as the outer corners are very much smoother in comparison and it is the marked difference that has thrown me. Should say that this piece is the first piece I have made on any machine that has more than one machined face or been made to fit; certainly the largest area I have faced off so far. More about the bored hole later.

I was facing off this block in the 4 jaw. It is about 44 mm square so an interrupted cut at the start. Knowing that carbide tools like to have the cutting speed up I was experimenting with the lathe speed and looking at the finish. First cut was done at about 450 rpm and result was nothing special though I had noticed that the corners seemed quite shiny. I had no immediate explanation and wound the speed up to 800 rpm and took another cut. The shiny area in the corners got bigger but the uninterrupted part of the cut was still nothing special. Putting the speed up to 1200 rpm achieved even more shiny area in the corners but again didn't improve the uninterrupted cut. So carbide does like the speed but is it the reduction in the surface speed as the cut gets closer to the centre that explains the poorer quality of the cut closer in. I really expected the outside interrupted cut to be worse than that closer in. Any explanations or ideas please

PVC pipe have a quite a bit of Thanks guys

I want to practice thread cutting on the new lathe and looking for recommendation for a plastic that will cut ok. I have heard 'Delrin' mentioned in connection with this sort of thing but happy to use anything really, the cheaper the better. It's practice in machine setup and technique which is the purpose and the first thread I want to cut is about 1 inch OD and 12 tpi. Going for plastic as I believe it's a cheaper alternative to metals 😊

Adam: DRO, I'm hoping that somebody will come up with a mod to fit a DRO to the SX2.7 in the not too distant future. The Sieg seems to have clear space in the places you would mount the necessary kit but I'm not experienced enough, or brave enough for that mattter, to experiment with that job yet 😀

Adam: I'm glad you asked that question as I too have a new Sieg mill and wasn't aware of the gib setup on these. I agree about the manual being very sparse, you have to 'know stuff' to perform basic functions 😊 I bought the mill with an R8 taper and glad I had asked about the differences between that and Morse tapers. ER32 collets are new to me as well but on investigating the set I got with the mill I find they are very similar to the collet setup in my Trend woodworking router. Lots of new stuff to get to grips with made easier by the helpful folk here when you can't find non confusing answers elsewhere 😊

Lots of useful hand cleaning info but would anybody care to reccomend a barrier cream they find works well and available in the U.K. I don't suffer with skin conditions on my hands and would like to keep it that way particularly as I am just starting again with machining etc. I have used Orange Swarfega for a good while and am going to start wearing some sort of gloves. I remember from my Post Office Telephones days that we used a barrier cream in the workshop but that technology will have moved on in the last 40 odd years hence this request 😊

http://Lathes.co.uk

You could try lathes.co.uk who have a huge list of machines for which they have manuals, diagrams, parts lists etc.

Edited By Nige on 04/06/2018 09:29:26

Jason: That is exactly what I am making except my block is rectangular to give me reasons to practice using use the 4 jaw chuck