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: Worm wanted for lathe|
It says 18DP right there on the drawing and the mating wheel is drawn as18DP 33T. The 5.75TPI and .174 lead are a little at odds with each other (0.17391 vs , 0.17450) I guess that they calculated half a thou per pitch is close enough.
Certainly, the engagement mechanism seems to be hit-and-miss enough to allow for a much wider error.
|Thread: Hardinge HLV-H|
What sort of work needs doing to the machines Stuart, and over what time frame?
Edited By Pete Rimmer on 08/01/2021 19:35:11
|Thread: Worm wanted for lathe|
Well, given that the kind gentleman has pointed you to the correct drawing on the Denford forum:
You now have all the info to produce your worm. Bonus if you can find a lathe which has 5 3/4TPI on the gearbox.
CVA has that pitch on the gearbox as does my Monarch.
Yes it does look as if it's only achieving half engagement. I wonder if the stops on the rotary lever can be adjusted? Might interfere with the operation of the threading interlock, if it has one, or knowing Denford they might have used the interlock AS the stop.
Looks like both original parts are cast iron. I see no reason why you couldn't make them from mild steel though.
For a permanent fix you could do a number of things:
Make a new worm and a new wheel to the original sizes.
Make a slightly larger worm and re-cut the wheel with a 1-off form cutter. Depending on the condition of the wheel it might only need cutting 10 or 20 thou deeper then you can increase the PCD of the worm the same amount.The wormwheel cutter would have to be the same OD as the worm itself and you can make it from a hardenable steel, using the 2-button method to get close to the correct form. Then you'd have to set the cutter at the helix angle, index the worm for 33 teeth and plunge-cut each tooth in turn. It's not as difficult as it sounds just a bit of work.
Yes you're right, lacking a drawing I used the figures you quote not giving any allowance for the clearance. It was more so you could compare what I think you should have with what you actually have. There would need to be a clearance allowance.
If this is your only lathe you could start by turning the worm gear over. That would put 90% of the load on the un-worn side. That would get your auto-feeds working at least towards the chuck but probably both directions since you'll have the worn part of the worm acting on the unworn part of the wheel, and vice-versa.
Then you're going to have to figure out the gearing to get a lead of 0.174" or 4.4196mm to make a new worm using a threading tool ground to 14.5 degrees which is ACME thread angle.
The drawing you're looking for is ML110_309 it's the drawing for the worm gear. It's a 18DP 14.5PA LH worm gear of 33 teeth left hand helix and 1.8334" pitch diameter.
Going by the specs on that drawing your worm should be I think 1.098" diameter 0.174" lead single start LH worm.
Edited By Pete Rimmer on 07/01/2021 22:26:36
|Thread: DTI Stand - Single Lock Type?|
I just bought one of the cheap ones for £14. I wasn't expecting champagne taste for lemonade money so I found it quite adequate given the cost. The base sits flat and the magnet will hold a DTI and a 2" dial gauge with the arm at full horizontal extension, so I'm happy with mine.
|Thread: Metric to imperial|
I would re-make the dials with 250 (or 125) graduations and save my brain from hurting.
|Thread: straight shank adapter for MT2/MT3 drill bits|
1. Buy a AEG/Wolf gutbuster which has a MT socket.
2. Hang on tight (or pay someone else to).
Edited By Pete Rimmer on 05/01/2021 20:55:57
|Thread: 130mm independent 4 jaw chuck, does it exist?|
5" = 127mm so just 3mm actually.
|Thread: Re-grinding 2 MT Socket|
Yes, not only that but the raised spot will tend to wipe the lapping slurry off the lap.
Tapers are easy to ruin by lapping because you can only lap in one position. It's easy to lap waves in a part. Far better to die-grind a lump into a hollow then lap very slightly for a good fit, than try to lap down a lump.
Edited By Pete Rimmer on 04/01/2021 19:10:34
If you want a professional outfit then spindle services in Coventry.
If you want to take a chance on home-grown grinding then anyone with a tool post grinder and a taper attachment or long-travel compound on a good lathe should be able to do it.
Another option is to tilt the head over to the taper angle and use a cermet insert in a holder on the table and machine it using the z-axis. It would require very careful setting up but it should work.
|Thread: Odd Screw size???|
I would say that too. 8.8 is a metric thread strength designation and 38/25.4 = 0.67 so I'd start by trying a M4 tap in the threaded hole.
|Thread: Camlock spindle|
There should be a sping and hardened steel plunger under the grub screws which acts on an indent to hold the cam in the 'open' position for removing the chuck. Could be they need winding in a little to give the springs a bit of pressure. Could also be that someone has had it apart and missed out replacing the springs orthings might be gummed up.
You'll love camlock. As John says above the cams stay closed by friction, no need to lock them shut.
|Thread: lost drive to power feed|
New gears made. Send me your postal details Mark
|Thread: Gloves and machine tools - my stupidity.|
Back in 1998 I was working in a tunnel invert, a guy was moving through a crawl-space with a large hilti drill. The low ceiling meant he was holding the drill - still plugged in - by the handle and the 16mm drill bit as he crawled commando-style. He inadvertantly squeezed the trigger, the drill wound his glove in and dislocated all of his fingers.
|Thread: First attempt at gear cutting|
That's going in at the deep end Steve. Nice one
|Thread: South Bend Heavy Ten Fixed Steady|
I have the same setup as you Roger, I'm pretty sure. Yeah the later 2-tumbler box would be much easier to do.
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