I screwed up!

Warco BH600G.

Treatment has really bit me in the arse today! Sometching I've been expecting for some time.

Had to reduce the diameter of a length of M10 studding to 9mm, so saddle in slow auto-feed as I had the whole length in the chuck, so sticking out the end of the spindle.

Having in the past tried to turn a long length of rod at too high a speed, with the end soon flailing about, I soon learned my lesson.

Only a short length out the back of the spindle this time, so no problem.

Except . . .

I forgot about the wood under the chuck that was resting on the bed!

CRUNCH!

WTF thinks I, lathe still doing its job on autofeed of course!

Then I notice the wood, so quickly disengage autofeed, stop the lathe, tumbler into neutral, tried to move the saddle away from the chuck, but cannot get the hand wheel to move, it's stuck.

Motor reverse selected, tumbler engaged, switch on, select auto feed on the saddle and with my help onthe hand wheel I manage to get the saddle moving towards the Tailstock.

With everything disengaged, machine off, the saddle handwheel eventually started to free up and move the saddle, but with free and tight spots, and with areas of no play to lots more on the handwheel dial.

Advise please as to what damage, if any, I have or could have done?

Geoff - Everyone tip toeing round me.

The saddle is moved by a small gear on a shaft (Grizzly part No 336) which engages with the rack on the undrside of the bed lip. It is geared to boththe feed shaft and the handwheel. During the jam-up the gear pushed away from the rack and bent the shaft slightly. So now it goes in and out of good meshing distance. The tight spots will be about every couple of inches along the rack ie per turn of the small gear not at the same point on the handwheel revolution owing to the extra gears in between.

Seen a few reports of this usually due to running into a saddle stop.

Hint for other users. Saddle stops are NOT meant to be used on auto feed though you can get away with it on Boxfords and Colchesters with a built in feed friction clutch.

Thanks Bazyle.

Found the part in the Grizzly manual.

Question is, what to do, do I leave well alone and live with it as is, or do I dismantle the saddle/apron to get to the bent piece, and then what?

Replace it or could the 'bend' be taken out?

Geoff - Seething at my stupidity. Everyone's boogered off! Must be me

Yup bent pinion shaft.

If it's any consolation did the same thing a while ago rushing to finish a job on the TOS.

Great stonking casting shot out the chuck doing 12,456 revs [ approx ] pushed the carriage back that hard and fast it sheared two teeth off the pinion, casting bounced off my bonce and smashed me cup.

Fortunately the cup came off worse, [ decent cup as well 5th dynasty Chinese Ming with 2010 CE sticker ]

Result one bent shaft, one tooth missing and one cracked.

So stuck a piece of Scrapbinium ™ in the lathe and using the topslide as a feed knocked a blank out.

Transfered this to the mill and using just a 1.5mm end mill and Art Fenerty's very clever piece of software called Gearotic milled a new gear on the end.

Resuly was after heat treat, one perfect new pinion shaft.

[edit] Crappy keyboard operator.

Edited By John Stevenson on 03/08/2013 21:10:31

If you have the space you can perhaps retro-fit a gear in the drive train with a clutch, it limits the damage greatly. Niko.

Geoff,

Do you have a pres of any kind? You may be able to straighten the shaft using the press and a pair of v-blocks.

Was it Sir Charles Parsons who straightened a car driveshaft by heating it in a bonfire and hitting it with rocks - somewhere in the alps?

Neil

P.S See John, I told you CNC was bad!

It just encourages people to break things!

P.P.S. I see that your ER25 Collet blocks have arrived at Arc in response to popular demand!

Edited By Stub Mandrel on 03/08/2013 21:18:40

I didn't do it on purpose, I was rather attached to that cup.................

I thought the collet blocks had arrived a while ago ? Not sure, that tight b@stard didn't send any free samples.

These chinese lathes have shear pins in the drive shafts (part 18) for which they use roll pins to make sure they don't suddenly break .. Replace that with a 5mm brass tube to fit. These tubes are found in model shops in sizes that slot into each other. Start with the largest that fits. If it fails under a heavy cut that isn't so heavy you want it to fail then insert the next smallest inside the large one and so on until you get a suitable strength combination. Alternative is to use a solid 5mm rod and turn a notch at the shear point to weaken it.

Search the12x36importlathes yahoo group for details about how to take the apron off. Think there was something about it in the last 12 months.

My Taiwanese lathe has shear pinson the lead screw and the feed rod, the one on the lead screw works! Just needed to grab the hand wheel while I was learning to cut a thread (sort of paniced), there were a couple of spares in the tool kit. Ian S C

Thanks for all the advise, much appreciated.

No press available Neil, but a good excuse to make one.

Nice idea speelwerk. Praat u die taal?

Will decide what to do once I've calmed down fully and can think properly.

Bazyle, I've been meaning to replace those shear pins with brass, but the usual 'will do them tomorrow' excuse.

Lesson learned so they are next before I use the lathe again.

I do so miss the clutch I had on the V10P!

JS, 12,456 revs? BH

That casting bouncing off of your bonce explains a lot

Geoff - 18 month old GD just visited, and she has lifted my spirits no end

Ironically my TOS has a feed clutch, a very good one, you can set the bed stop and if it hits it the clutch just slips

In my case though it wasn't a jam up but a big casting coming loose and hitting the carriage throwing it back that hard it sheared a tooth and cracked another. Some thing that can't really be designed against.

Totally my fault for rushing.

Stub Mandrel - I would like to know more about the (possibly) Sir Charles Parsons story. Please do you have any more information?

Thanks

Ja, OuBallie, dat is de taal waarmee ik ben opgegroeid. In early days I worked on a AI-Hembrug, a lovely small lathe with fine working feed clutch. Missing that on the Myford I now use I fitted one on the wide gear in the gearbox. It works fine and for threading you change it for the normal non-clutch gear.Niko

speelwerk,

I and no douby others would appreciate details of the clutch please.

Geoff - Time for nosh

Hi Merlin,

I'm sure I read the story in an old ME, that contained a short biography of teh man. I'll see if I can find it in the indexes.

Neil

It is not much work to fit a clutch to the wide gear in the gearbox of a Myford. I bought this one from Madler **LINK** , for little extra money they make the hole to your specifacations. With little work you make the wide gear to fit the clutch and adapt a longer Myford toolpost nut to place everything on the gearbox input shaft. I have placed a few pictures in my album of it. Niko.

Dank U speelwerk, the perfect solution! You have made my day!

Wonder how many knew about this nifty devise, I certainly did not.

Now I can duplicate that V10P feature I so miss.

Geoff - A skipping with joy.

Finally got everyting off and I'm now ready to pull the drive shaft out, the one that provides drive for longitudinal or cross feed.

Before I do, however, is there anything running in the keyway that's likely to fly out into that black hole in the workshop?

One thing I did notice, was that when I loosened the two cap screws that hold the Apron to the Carriage, there was no more binding on the handwheel.

With the Cross-Slide off, I now have the chance to do the Anthony Mount modifications, plus any others anyone can suggest/recommend please..

Geoff - Need to make 'C' spanners (Advice anyone?)

Up date at last.

The usual delay due to treatment:

The Cross-slide had already been removed in order to mill extra T-slots ala Anthony Mount's modifications.

A change to my lathe compared to his, was that the nut is bolted in place, resting up against a shouldered bush thus alleviating the need to measure and then knock it out.

Apron removal:

1) Knocked out the roll pins from the Feed and Spindle Direction Rods (shafts), but couldn't move the collar over the Leadscrew roll pin, so left it I place.

2) Removed the Rod End Cap that supports the ends of three Rods (shafts)

3) Went to knock out the roll pins that align the Apron on the Saddle, but noticed that they where threaded, so for once the gray matter worked and I proceeded to insert M4 screws into them, even though the Grizzly Manual says roll pins, and Anthony Mount had roll pins in his BH600G.

Once the screws where in place the dowels where easily prised out, just leaving the two recessed cap screws to be undone to free the Apron.

3) Apron suitably supported, it was just a case of sliding it along the Leadscrew until it was free then onto the workbench for examination.

4) Said inspection soon revealed that the Gear Shaft had bent where the collat on the shaft butts against the Apron casting, so it needed to come out.

5) Roll pin securing the Spur Gear to the shaft, but this time instead of the pin coming out with light biffs of the hammer, I had to resort to GBH/ABH to even getting it to budge.

Eventually it did come out, but tinkle, tinkle, tinkle into the Apron bottom. Three pieces, due to the fact that the holes don't line up!

6) I then had to resort to a large diameter drift to do more GBH to get the shaft and gear to part company. Oh how I HATE doing this to a 'precision' machine, it makes me cringe. Needs must though.

Said Gear Shaft soon popped out, cleaned, then into the 3-jaw to see how much damage I'd done.

All I did was hold a length of 5mm ø aluminium tube, to replace the roll pins, against the front way and just touching the shaft between the shoulder and gear.

Well, it sure as heck didn't need a DTI to measure the runout, as it showed 1/16"-3/32" (1.6-2mm). BH etc was my reaction seing that.

7) Now how to straighten it. I had watched my Old Man do miracles with metal, either making or fixing, so I hoped some of his talent had rubbed off onto me.

After two feeble attempts with a drift and club hammer, yes I know pretty useless, I said to meself, "a vice is just a horizontal press is it not" so off I went and the set-up is in my new Photo Folder.

It needed two attempts of heaving on the vice handle to get any movement in the shaft, but the bend was reduced to approximately 1/32". One last try, this time slipping the handle of my long/big shifting spanner over the end if the vice handle I was able to give it an extra bit of heave-ho.

Left overnight again and now the bend would need a DTI to measure properly, but definately around 1/64" or less.

Decided to put it all back and try. Easy to take apart again if needed.

8) While the apron was off, I decided to drill and tap M8 drain holes in the bottom of the casting, then cleaned it out using the parts washer as I had seen CI swarf lying inside the casing, there before I did the drilling and tapping.

Back on the bench I saw the Cu pipe mentioned by Anthony Mount that disappears amongst the gears, it getting oil from a reservoir machined in the Apron top facing, fed via an 'Oil' plug in the Saddle, with this reservoir also feeding oil ways along the front edge of the top facing join to the Saddle, with holes drilled from it down to various spindles.

Now! unless the lathe is slightly Tailstock high and rear high so there is a slight slope, there is absolutely no way the oil is going to flow.

I will see where I can add spring oilers with/withour pipe/s attached as Anthony did on his Apron, to do a better job of getting oil to those gears.

8) While removing a semi-hard almost black substance (grease?) from the two worm gears that provide power to the gear train, I noticed that one of the teeth on the bronze worm gear was badly mauled, with another just slightly so. Anglo-Saxon rend the silence on seing this!

Seing that the Saddle and handwheel moved freely when I had loosened the Apron securing cap screws slightly, I will leave well alone for now and see how things go.

Thinking ahead, what lubrication is recommended for those hard to get at worm gears please.

This post is long enough, so calling time.

Geoff - Oh so much cooler today!

Photos photos photos please Geoff. There is precious little info on what the guts look like. And include ruler in the shots too if you can. Think of the questions you had when you were starting this process and provide a photo to show.

Also please can you get a shot of the underside of the saddle. I'd like to know what recesses are moulded in to know where can be drilled without going through.

Lubing the gear is a toss up between grease to hold any swarf but otherwise stay put or oil to run off. Might be the time to put a little copper pipe in and up to somewhere normally covered by the cross slide but accessible when that is run forward.