Member postings for Pete Rimmer

I stand corrected the gear should be 24 not 20. A 21 in place of the 24 would give the error the OP is seeing.

It sounds like you have the wrong stud gear on the tumbler. Perhaps it has a 21 or 22 tooth fitted? 21 would be more normal to find there but it doesn't quite fit with your selected vs actual TPI results.

Have a look in the spares box for a 20T gear and fit that, it should correct your issue.

That surface plate is in superb condition. The scratches detract from that hardly at all. It has a cover so it was probably a grade A. Looks about 12" x 10".

Set the title as "cast iron surface plate with cover". Post the size in inches and if it has a tag on the edge put that pic in the auction. You should get £50 minimum.

Those "solid steel blocks" will doubtfully sell at the price IMO.

Some of the detail in those Slater videos leaves a lot to be desired. Clocking for 0.001" TIR using a mag mount dial and rotating chuck is poor practice and their animation for rotary broaching in the lathe shows the broach wobbling as it would if it were done in a mill.

The axial off-set is in the bearing pocket in the MT shank. The broach holder itself is machined all concentric.

As Malcolm very insightfully put, you should see no wobble in the broach, it merely turns on its axisbut the axis is off-set to the axis of the holder making it cut.

Wobble broaches do not spin with the work, they are merely driven by a holder which wobbles. This is a wobble broach I made quickly to cut a 12mm hex pocket. It doesn't turn with the part as you can see.

Wobble broack working

Description

Edited By Pete Rimmer on 04/07/2023 06:56:22

That's correct, it's further in but still doing the same thing, shaving a small amount ahead of itself each rotation.

If it's in the tailstock try moving the tailstock off-set a tiny bit. If you were looking at Malcolm's sketch above move the tailstoks off-set in the downwards direction.

The principle is very simple. If you look at Malcolm's sketch you'll see that the bottom edge of the tool is inside the hole and the top edge is outside. This means that the point at the top will be more to the left when it's made half a turn to get to the bottom. The end of the broach is the cutting face and it plows the metal into the hole as it turns. All you have to do is push it.

How is the broach holder being held? In the tailstocks or in a toolpost? If it's in the tailstock then check the spindle to tailstock alignment. If it's offset a bit there might be enough bend in it all to cancel out the 1 degree axial offset.

If it's in the toolpost check that you actually do have the offset angle and that it's not turned to cancel it out and present the broach face flat to the work as it won't cut like that.

In either case you could try adding a little lateral offset and see if that helps.

There is never a good reason to lap in machine ways. It's the exact opposite of what a moving way requires to be properly lubricated. You might (probably will) see an apparent improvement in function in the very short term but once done, wear will be highly accellerated.

It's a pretty good way to ruin a machine in short order.

Yes as Michael says above the 110v tools are powered from a centre-tapped-earth isolating transformer which means that the maximum potential is actually 55v RMS.

You could get a lethal shock from it, probably, if you're working around sea water. I know that I've had a few tasty ones when the tools have got salt water in them when doing marine work. Many modern small tools have smart triggers which the salt water plays havoc with. One job I did (cutting the sea walll opening for the new tyne tunnel) we had to keep a barrel of tap water handy to jetwash the gear through at the end of every day then leave it in the drying room to dry out for the next shift.

IMO they will never swap out 110v centre-tapped earth for 240V RCD protected site tools, and it wouldn't make sense to for several reasons:

1. Most small tools which would traditionally be run on extension leads are now battery operated. Some main contrctors actually require it.

2. Where you have a transformer right now with 6 or 8 outlets on it you might only get four (expensive) RCD-protected ones.

3. Building sites by their very nature are exposed to the elements. Running 240V leads all over with RCD protection is just a recipe for nuisance-tripping which costs production and if it's the supply that's faulty it'll cost the site standing time.

4. The incidence of injury from 110v power by electrocution is very, very low. Why would they change it especially when everyone already has the equipment?

150kg is only 50kg each for 3 good sized lads.

Can you measure the head diameter and threads of the lower ones. If they are 35mm head and M22 x 1.5 thread I can maybe use them if there's a usable selection.

Supported either end, cross-bars between the front and rear spans every couple of feet just to support the chipboard shelf.

If you want to know about deflection for 200kg load just get a piece of the steel, span it across and get two chunky people to hang on it in the middle.

4mm thick is miles too heavy. My high-level shelving is made from 40x40x1.6mm thick and it spans 2m+. It's loaded up to the nines with no sign of distress.

I've even made a rack to hold the working heads from my mill which are up to 50kg each. The rack is just short lengths of this same box section welded to the wall frame one end and they too seem to hold up with no issues.

You shouldn't use an unqualified plate as a master for scraping a reference piece like a straight edge. I mean it'll get you fairly close but you would not believe how fast you can wear a dip in a granite. At the very least, print it in both diagonal directions and compare the results. If they are not exactly the same, the plate is worn. Even if they are, the plate might still be worn but you will likely see a difference.

Shame you aren't closer to Kent I could lend you a good straight edge as a reference or even lap your plate to grade 0 for you.

I have several of his pieces the iron is a joy to scrape and as you say the quality is right up there.

What are you using for a reference Taf?

If they are 13" long they are probably silver steel.

If your machine has the cross-travel you could make some sine centres and drive one end with a dog.

I have a 600mm mitutoyo digital height gauge here with corroded electronics. If anyone fancies that they stand a good chance of repairing it, they are welcome to come and take it for free.

The encoder WAS working, though the plug had been removed and the wires soldered direct to the PCB due to the corrosion mentioned. The battery box is intact but heavily corroded from a past leaked cell which is what I think caused the rest of the corrosion prior to my owning it. The LCD display was hit and miss when I got it, it would come on and then fade out within seconds, or sometimes come on and stay on. It had suffered a couple of repair attempts and now does not come on at all though that is a recent development. It seems the electronics are actually functioning to an extent as the led comes on when the power switch is set to the middle position which I think signifies output to remote display.

Anyway, it's here, it's scrap from my perspective. I'd love to make it work but my electronics knowledge is weak, so if no-one wants to pop along and collect it, it's going in the bin.

It's the same as the one in the link below, except it's in bits and has no scribe or clamp. All of the parts are there for it to be potentially repaired however.

**LINK**