|Nicholas Hill||25/06/2019 20:59:28|
|22 forum posts|
last night I adjusted the Top Slide Base on my Super 7, and noticed the screw give totally. Much to my surprise, I discovered the cone had cracked into two pieces.
As a very temporary fix, I have glued it back together with super glue, but as it was impossible to match the granules it now creates a very tight fit.
Today, I tried all the usual Myford spares people, and no luck. I am happy to wait for one to come up on ebay, but that could be a while. So I was wondering if there are any suitable alternatives?
Hemingway seem to produce a couple of options - The Gibraltar, or the Improved Top Slide.
So, I was wondering if a) Anyone has any suggestions of where to find a replacement. b) has anyone else machined with a super glued Top Slide Base, is it really really stupid? c) Can I use this as an opportunity to buy an alternative?
I have attached a couple of pictures of the slide base, to show the type, and the repaired crack.
Any help, ideas, or just mocking, will be gratefully received.....I feel somewhat lost without my lathe.
|John Haine||25/06/2019 22:42:20|
|2543 forum posts|
Who needs a top slide?
|Simon Collier||25/06/2019 22:51:18|
295 forum posts
Would it be possible to machine away the damaged spigot section and turn a replacement and screw it on? I'm only going on the photo as I am unfamiliar with the S7 topslide. You'd need access to another lathe, of course.
3651 forum posts
I think I too would be looking at the possibility of turning up a new cone from steel and attaching it with screws. You might get lucky and be able to swing the topslide body in the lathe after attaching it to the faceplate. You could then turn a recess for the new cone to locate in. Would be stronger than the original.
If you need to get by in the meantime, a rear toolpost can be pressed into service as a Gibraltar style solid toolpost mount. I use mine that way a lot. Works very well. Or any block of steel suitably machined would do the job. Can all be milled in the lathe with a flycutter by clamping the block to the cross slide, or even faced off on the faceplate. Slot for mounting tool bits in can be milled with end mill held in the three jaw chuck and the toolpost block packed up to suitable height. I've done several of my combo rear/Gibraltar toolposts that way.
Or a simple spacer block with a commercial quick change toolpost mounted on top would be simple to make too as per posts above.
|Kiwi Bloke||26/06/2019 07:44:54|
|187 forum posts|
No mocking, but lots of sympathy. What a horrible mishap. I'd imagine that a top-slide could be obtained from a wrecked 7. Easy enough to scrape the base to your existing slide. Otherwise, make a new 'cone' as suggested above.
|144 forum posts|
I have no idea how this slide works or what loads the broken piece has to take, or how accurate the piece has to be, but I've had great success using JB Weld to put broken pieces of metal back together. Always best to repair if you can, hope you get it sorted soon.
|3083 forum posts|
It is not a big task to have one made from a block of Cast iron, takes time and a working lathe, Someone may make an offer if you cannot find a replacement.
|1266 forum posts|
I'd be very tempted to just get the Radford Improved Top-slide Nicholas.
I was thinking about this again yesterday - when the slide was hitting the tailstock (as usual). I don't taper turn very often and I think the Radford design would be generally more convenient. He claimed it was a lot more robust/secure too. I just need to finish all the other things first...
But you have more motivation to do it...
|Adrian 2||26/06/2019 10:24:20|
|66 forum posts|
I wonder why it has cracked ? Are the thrust pads present and correctly installed in their respective holes? They are handed and easy to fit incorrectly.
|Nick Hughes||26/06/2019 10:35:54|
196 forum posts
The Dutch "MyfordSolutions" have the base (A2076) listed:- MyfordSolutions
|Clive Foster||26/06/2019 10:51:09|
|1737 forum posts|
The root cause of the failure is that the locking screw applies pressure on a relatively small area. Doesn't help that the small size of the Myford doesn't leave room for really robust components. But such failures are rare so the part is almost certainly plenty robust enough for all normal duties, and many abnormal ones given that most Model Engineers habitually overload their machines on occasions, so its almost certain that there ere cracks inside the casting from day one. You just got unlucky.
I think cleaning out the recess in the middle properly, ideally sand blasting to get all paint and grunge off, then filling the whole thing with good quality metal loaded filler should prove amply strong enough. Typically industrial rated metal loaded fillers said to have a strength approaching 1/3 of ordinary cast iron. There is a lot of bond area so strength of the repaired component will be at least comparable. Maybe better as the load is less concentrated.
Important to get the proper thing Devcon, Loctite Fixmaster et al as these are formulated not to shrink on hardening. Cheaper versions will probably shrink slightly. Not normally an issue as, usually layers are thin and / or there is a free side to take up the slump when hardening. JB Weld does shrink noticeably in big lumps but it thins out during the hardening process and should flow into the filled space to compensate so it might work here.
I do know of SouthBend, and Boxford machines that have been repaired by turning up a new cone and fixing it in place with screws. Steel would probably be fine but I imagine cast iron would be better. I would put a 1/2' or 12.5 mm diameter registration hole in the main casting and turn a matching spigot on the new cone. Six small countersunk head screws, 4 mm should hold it just fine if backed up by adhesive. One of the stronger SuperGlues or, better something industrial from Loctite or similar suppliers.
Unfortunately Loctite have dis-improved their website and literature. Again! Year or two back they had some good wide-ranging guides to actually using their products as opposed to specific applications. Which seem to have disappeared. Maintenance solutions guides here :- **LINK** and here **LINK** can be useful. Fixmaster metal rebuild application notes here :- **LINK** . The official version has gone all interactive which is slightly less useful than a chocolate teapot.
PS Not a Loctite fanboy but they do have the range in on place!
Edited By Clive Foster on 26/06/2019 10:51:38
|Nicholas Hill||26/06/2019 16:35:33|
|22 forum posts|
I am rarely on here, but whenever I have problems that have left me searching, this site always seems to have incredibly helpful people to give one light at the end of the tunnel. I now have three routes to try - a source of the part, a suggestion for substitutes, and suggestions for repairs.
As for the cause of the cracking, I am still slightly lost. I had a nasty incident while parting off a week ago - 1 second my parting tool was cutting easily, and then with no noticeable force, the end 1" suddenly broke off. I was cutting EN16 of 1/2" at 250 rpm, So no excessive forces. I immediately completed the cut with my Eclipse blade, with no problems. I have since done several hours of work, again with no issues. I then adjust the Top Slide, and just the force of hand tightening, caused it to crack.
Being a secondhand lathe, I don't know it's past life, but would have thought a 40+ years old lathe, would have shown any major faults prior to now.
It maybe that my tool height was not correct. I had great problems with good finishes initially, and found the 3/8 shank tools was about a 1/32 too high, at the lowest setting in the Dickenson quick change tools post, so had to grind them slightly. This I found slightly odd, as the tools and post are designed for the Myford..
So it might be, that I had the tool at the wrong height, and it dug in, causing the tool breakage, and the initiating of the crack...
I have a Rear Tool Post, and the Myford Cut Off Slide, so may experiment with those. I really am not good at parting off, so after this, will probably use them as a safety first solution.
I am tempted by the Improved Top Slide, as I have a Taper Turning attachment, and the tail stock is a pain - one has to faff with angles, and loss of rigidity due to the over extension of the tail stock.
Anyway, I am more thinking allowed now, than coming up with solutions.
Many thanks, again, I shall ponder the ideas, and decide later today. So hopefully my lathe will only be down for a short while. I need to make two axles for my 1927 Omega Motorcycle. It is grey out today, but the weather is supposed to be good for the weekend!
|Alan Jackson||26/06/2019 17:37:11|
161 forum posts
How about converting it to a Lever locking topslide?
138 forum posts
Nicholas, I had exactly the same happen to mine. Again, a secondhand machine in otherwise really good condition, although I have had the odd screw showing signs of overtightening.
I was lucky enough to have a topslide on the bench that I had acquired from fleabay, with a view to trying out the GH Thomas improvements. So I just swapped out the bases and carried on. Since then, I have also begun to use a rear tool post, which dramatically improves parting off.
Remember that the Radford improved topslide does not swivel, nor the Gibraltar.
138 forum posts
Nicholas, just found the thread relating to my previous discussion about this....
|duncan webster||26/06/2019 19:02:27|
2108 forum posts
looks like this isn't unusual see **LINK**
I'd go for John Haine's solution at least as a temporary measure. Topslides are always in the way, and you don't use them very often, at least I don't
|Nicholas Hill||29/06/2019 20:22:27|
|22 forum posts|
Just an update. Super gluing top slides does not work....lasted about 30secs, and then went again.
I have ordered a Improved Top slide from Hemingways. After telephoning them, it seemed to be a all-round better solution. It compromises the flexibility, but gains rigidity, and hopefully better finishes.
In the interim, I decided to do a vibration survey of my lathe. Just using an App. It's quite interesting too see that minor changes make huge differences. So the time hasn't been entirely wasted.
Anyway, many thanks for all your help, and advice.
It was most reassuring to see Colin had the same problem. It stopped me kicking myself so much.
138 forum posts
Nicholas, I would be equally interested to learn how you get on with that Hemingway kit.
But dont let it stop you rushing out and buying a rear tool post. They transform parting off, and I see there is one for £25 over on Home Workshop right now - ad 35748.
|Chris Trice||30/06/2019 01:08:23|
1362 forum posts
I built the Hemingway kit about ten years ago. It's a nice bit of kit BUT I've never had cause to use it and it's languished in a drawer ever since. I ended up custom making a beefier and larger top slide of my own design that still allows taper turning.
|Niels Abildgaard||30/06/2019 08:12:39|
|215 forum posts|
How do You do that?
Sounds very interesting.
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