Harrison 300 Swarf Shield

Hi Everybody,

My lathe is stripped down now and the major clean up has started. The bed was absolutely choked with swarf particularly under the head stock. Made a mental note to make a shield and then discovered it should have one! It's shown as part number D650H4001 on page 33 of the manual under Bed and Cabinet. No fixings are shown and obviously no dimensions. On the bed there are no obvious attachment holes.

This bit of tin is typical of the small bits that get lost in industry because they seem to have no importance until swarf fills the head stock pedestal and then works its way into the change wheel enclosure.

Not even going to try and get one from Harrison so any info or advice would be very much appreciated particularly how it attaches.

Hi Len,

On my M300 it's item 24 in the parts manual but has a different pt no to your suggestion. It is held in place with two small screws that screw into a couple of tapped holes in the bottom of the headstock casting.

Cheers

John

Edited By elanman on 06/09/2020 13:30:52

Hi John,

Thanks for that. With so few replies I was starting to think I was imagining things. Job is now done. Pic1 shows the cavity under the headstock. Pic2 shows my manual. Pic3 shows the plate I made and the drillings I made into the headstock.

I think Harrrison may have deleted this item to cut costs.

Regards,

Len.

With out wishing to side track the thread.

Your pictures high light something I have never noticed before.
I was going to offer up a solution I used on my M300 gap bed.
But looking at your pictures I am surprised to see that Harrisons seem to have used totally different casting designs for the non gap bed and the gap bed.
The manual whilst showing the two beds do not show the differences in design.
Your non gap bed (correct me if I am wrong) appears to have swarf clearance through apertures in the rear wall of the bed.
My gap bed just has vertical clearance holes through the bed and a plain back wall with mounting facilities for accessories.

The question I would like to ask, is do you have on the back wall of your bed a plain area with tapped holes for mounting accessories?

Mike

Hi Mike, feel free to side track to your hearts content. You are right. It's a plain 600 bed with clearance holes through the back wall. There are machined pads about 2x3 inches on both the front and rear faces. Not sure what they are for as I have nothing to bolt into them. Pictures attached.

Now here's another side track. My picture showing the cavity under the head stock also show the oil level sight glass. It needs a serious clean or replacing. How is it removed?

Len.

Ian,

My 1999 M300 has the plate attached from new.

On my M300 the rear pads hold a beveled pattern bar for a hydraulic copying unit:

The front pads carry a trip bar for an Ainjest high speed threading unit:

The Ainjest unit is bolted on the right hand side of the saddle and the rectangular trip bar runs the full length of the bed below the electrical actuator rod.

Andrew

Hi Andrew,

All I can say is thanks for the knowledge and the pictures. Whow! Your attachments must be worth a squillion quid. At least I know what to look for at the local car boot sales.

Andrew has prempted me regarding the use of the mounting pads.

As for the oil sight glass I don't think it is possible to clean it. They are made of plastic and the oil ends up permanently staining and deteriorating the plastic. Mine is almost totally opaque. Impossible to use it to check oil level.
Not using the lathe as hard as industry, I haven't lost any noticable amounts of oil over the years. I occasionally lift the top off the headstock to check.
I doubt very much if replacements are available, would be interested to know if they are.

Mike

Hi Mike,

You are right about the sight glass deteriorating and being effectively useless. The Harrison part number is DW4064A(ADAMS). Checked out Adams on the web and they still exist making sight glasses. Look like a blue chip company so suspect even if they could supply a replacement it would be very expensive. Not hard to make a new plastic disc or even a glass disc but how to get the housing out without damage is the problem. Think I might be pragmatic like yourself and just lift the top cover every so often.

Len

On machine tools these sight glasses are almost invariably simply pushed in to a cleanly bored hole.

Thin metal housing flange distorts slightly to grip and seal against negligible pressure. Theoretically they can be punched out without damaging the thin flange and a new window fitted. Maybe a wooden dowel just the right size pushed from inside. "Are you feeling lucky"

Quick google for oil sight glasses turns up a fair number of suppliers, prices from £5 to £15 (ish) seem common.

Most common are screw in units for hydraulic systems working under significant pressure. But I guess the glass / plastic window could be extracted and inserted into a push in flange.

Or this looks promising **LINK** push in, range of sizes but probably a bit spendy.

Clive

I agree with Clive that the sight glass was probably a push fit, possibly with an "O" ring.
With your lathe in bits you are in a better position to find out.
I am certainly not taking mine to bits to find out!

Out of idle curiosity. Just going back to the swarf shield, which in your pictures is screwed to the headstock. Did those tapped holes exist or did you drill and tap. My headstock has no tapped holes.
The swarf shield is as illustrated in the manual and is sprung and wedged in to the cavity.
You have swarf clearance directly under the chuck, which of course the gap bed doesn't have, so there is a much greater build up of swarf adjacent to the headstock on the gap bed.
Just wondering if Harrisons thought it was a necessary item on the non gap bed lathe. Especially if accountants had a say in the matter!

Mike

I have just noticed you said that you drilled and tapped the holes.
So my question is void but maybe the conjecture still stands!

Mike

Hi Clive and Mike,

Thanks for all that. Firstly the swarf shield. Yes I did have to drill the holes as none existed. Fortunately the lower edge of the head stock is a half inch flange so the holes don't break out into the gear box. They are not tapped. I would have needed to make a very long extension to do so. The plate is simply held in place by two small self tapping screws. Not pure engineering but adequate and better than nothing. I can't really comment on a gap bed as I've never seen one, but I think my problem was exacerbated by the lathe operating with a collet chuck for most of its life. At only some 5 inches diameter it leaves the cavity very exposed compared with a large 3 jaw.

As regards the sight glass, made a decision! It's useless as it is and practically impossible to get at from inside the gearbox Self tapping screw and slide hammer. Brass plug if it all goes pear shaped. Will report back.

Len

Removed the sight glass with a slide hammer. The lens was destroyed but pic1 shows the remains. Tin housing and two O rings.

Made new lens from 3mm acrylic as a press fit onto the lower sealing washer.

Unfortunately got it wrong and distorted the back of the tin housing with the two holes. It pressed against the lens and gave a horrible indication when tested. Turned the back of to give a clear disk.

It should work. I think the twin hole back plate is just to stabilize the level reading when the machine is running.

The lens was sealed with bearing fit. Spent more time on the web trying to find a replacement (they were all the wrong size) than it took to fix mine.

Just an update, the repaired sight glass did not work. The tin housing distorted badly when being pressed in. Either I weakened it too much by machining off the back or over expanded it pressing in the lens.

Found an excellent solution but as it's a bit off topic her have made separate post under 'Harrison M300 site glass'.

Thanks to all.