Here is a list of all the postings Pete Rimmer has made in our forums. Click on a thread name to jump to the thread.
|Thread: Metric ML10 lead screw threadform|
True that, but then my Denford lathe had a cross slide screw that was 1/2" OD x 2.5mm pitch. They just used the same material and cut a 2.5mm thread in place of 10tpi. Weird things happen.
Pretty easy to get the angle with a gear tooth caliper and some basic trig. I guess I'll grind a 30 degree tool in preparation and check the original screw when it gets here.
It's certainly 3mm pitch.
Assuming the screws were made in house, they could easily have used the same tooling for both.
That's what concerns me, or rather that they might have used a 8tpi insert and set the lead to 3mm.
Edited By Pete Rimmer on 25/04/2018 08:53:27
I thought the same thing about them all being 8tpi because of the ML7 being so but the screw is certainly 3mm pitch. It's confirmed on the lathes page that they did make metric ones.
I can't think why they would make a metric pitch screw with ACME form but you just never know.
Does anyone know if the metric lead screw for the ML10 is trapezoidal thread or ACME? OD is 16mm with 3mm pitch but I don't know the form or if it's full form or stub form.
If someone had a factory print that would make my day!
|Thread: Silver soldering contradiction|
In my work we have a guy that re-tips drill bits with silver solder. There's a spring clamp that presses the tips hard against the drill to solder them. These things see extreme duty and they are soldered with no gap.
|Thread: Argon gas|
You can only get argoshield light on the hobby deal, not heavy.
If you are using it for your hobby then BOC do a deal which is a lot cheaper than list. Current hobby price for argoshield size y is £47/yr rental and £35.71 fill with 79p surcharge. Plus Vat.
If you're a very light user and mean to keep the bottle for a long time then a rent-free would be better.
|Thread: Trying to find some D1-3 back plates|
I've made a couple from steel and also from barbell weights but the weights tend to be too thin so the pin threads poke through. You also have to be careful with the locking screw hole because at first glance they appear to be on the same PCD as the stud holes but they are not. For my own use I tend not to even bother with locking pins I just drill and tap for the studs, screw them in and use it.
As for the taper I tend to make it snug. It's almost as shallow as a Morse taper and you can see those visibly move when you set a taper in your tailstock with a soft drift even after setting itin by hand, so there's more tolerance than you might think. A loose fit of course is intolerable for the camlock taper.
|Thread: Correcting an off bored cylinder|
Is the hole in your chuck bigger than the cylinder hole? If so, turn and bore a piece of round or flat stock that plugs into the centre register of the chuck and superglue in in place on the flat end of the cylinder. Now use that plate to locate the cylinder centrally on the chuck, hold it tight against the chuck face using the tailstock ram and and snug up the four jaws with the soft packing until you have it held for boring.
|Thread: Does 4 jaw chuck quality matter|
Not only does quality matter but suitability does too. I have a couple of Burnerd lightweight 4-jaws and whilst you can't question the pedigree of the chuck you do have to be careful how much you tighten the jaws or it's easy to put a deflection in the chuck face. I guess that's why they made them with such small screws and chuck key.
|Thread: Lathe chuck not true.|
Grinding the jaws should only be a last resort IMHO and only after careful checks have been made. If you think about it, jaws are hardened steel and a very compact and strong shape. Chuck face is essentially a flat disc of cast iron with three slots milled in it. If something's going to go out of shape when abused it's more likely to be the soft iron chuck not the hard steel jaws.
I had a 4 5" PB chuck with severe runout that varied between 8-15 thou and I suspected the jaws until I put them into another similar PB chuck and they were perfectly fine. Turns out the slots in the front face of the chuck were dished and it was holding the jaws bell-mouthed, probably from being abused by over-clamping something held at the extremities of the jaws.
Consider also the commonly accepted statement that grinding the jaws is only good for the diameter they are ground at. That is exactly what you would expect if the chucks jaw guides were dished or domed.
Edited By Pete Rimmer on 02/03/2018 18:24:30
Edited By Pete Rimmer on 02/03/2018 18:25:01
|Thread: Diamond grinding wheels|
I use diamond for stellite, usually I use it for grinding threading tools as it holds an edge so well. You can get it sharp enough that you have to handle it with care. Doesn't seem to bother the diamond, once again if used at slow rpm. Bit hard to find stellite now though.
You can use diamond wheels to put an edge on HSS all day long so long as you turn the wheel slowly enough and even better if you use a little coolant. Electroplated diamond products have an initially aggressive cut but settle down to their 'normal' cutting rate quite quickly and stay there a long time so long as you don't overheat them.
Once worn beyond their normal usable life they can still be used to put a very fine honed edge on something but the material removal rate will be minimal.
|Thread: Problem with Little John Mk2|
If you run the test cut again with a larger diameter part and you're still getting a taper then take a look at this video done by a friend of mine a year ago. He doesn't mention how or if you can adjust the spindle angle but I could ask him for you if it turns out you're turning a taper due to a mis-aligned headstock. Many lathes can be adjusted on the clamp bolts:
Edited By Pete Rimmer on 25/02/2018 09:03:20
What diameter was the part you've done your testing with Steve? It might be nothing more than the brass bar is bending away from the cutting tool but as you get closer the chuck the spring in the part is less so it's forced to cut deeper.
Run your test again with something of fairly large diameter but not too long - say 1.5" diameter with only 3" sticking out the chuck. Take a light surface cut and see what result you get.
Edited By Pete Rimmer on 25/02/2018 08:49:58
|Thread: Couple of things at Lidl|
Ok thanks for the review Clive. It 's a shame that 6" discs won't fit but there's always 4" discs, which will still do the job just that you'd have to be a little careful not to run off the edge.
The 15min duty is no problem lapping a carbide scraper usually takes more like 15 seconds.
|Thread: Colchester Bantam 2000|
You won't and it probably wouldn't help you anyway. IIRC the Bantam cross slide screw is a 2-start thread. .100" pitch but 5tpi lead.
|Thread: Couple of things at Lidl|
I had suggested trying out this as a cheapo carbide scraper grinder. Trouble is, the most common size of diamond flat lap disc is 6". Do you think a 6" disc might fit with adaptions? If not, it would be restricted to 4" discs but they would still do the job.
|Thread: Parvalux motors - highly recommended.|
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