Boxford 240 TCL Gas Strut/spring for door

Hi all,

I've been restoring an old Boxford 240 CNC lathe and when I bought it the gas strut for the clear door was missing. I cant find any references to it online and have emailed boxford who couldn't help. If you have one on yours that works, I'd really appreciate if you could share the measurements, in particular the force value in newtons to support the door. A close up photo would also be great.

My best guess from photo measurements in that its a 15/16mm cylinder and 220mm long fully extended but my calculations for force seem to high so would love to validate.

Many thanks

Andrew

Mine may be slightly different as it looks like someone has added an extra bit of plastic to the bottom of the door, which appeared to be too heavy for the original strut. I'm not fully sure if this is the case, or if my strut had lost some force but either way I increased the strength of mine.

The dimensions were:
- 200mm extended
- M6 threaded rod
- 8mm diameter ball ends

I measured the force of the original to be between 20-25kgf. My replacement was 300N and I purchased it with the optional dust cover. (NS-FF-6-80 from Metrol) I then realised that my original plastic ball ends were too worn, so I replaced them with these: https://www.sgs-engineering.com/b6-metal-ball-socket (I used the original balls)

You may want to try the 250N version, I'm not fully sure. They are horrible to install, I used a cheap ratchet strap and destroyed the strap's webbing in the process.

Thank you so much for this information. I really appreciate all the detail. I was originally going to order 400N but your suggestion of 250-300N sounds like it might be more appropriate. So hard to calculate using the online calculators give the door has more weight at the back. So from your info it sounds like a 15mm strut with 8mm cups and a distance of 213-221mm (cup centre to cup centre) or thereabouts is the way to go.

I will post back here after I install with my experience and photos for future reference. Thanks again

Andrew

If you are not certain of the required force, you can get "adjustable" versions. When they say adjustable, they mean you can let the gas out but not back in again. But can be a handy way around the question of what model you need.

Thank you Muzzer and yngndrw for your assistance. I ordered the 250NM strut in 6/15 size and 220mm extended length (centre of cup to centre of cup) and it fit perfectly. I also ordered 8mm metal ball cups and the strut came with 10mm plastic cups but I found the plastic ones fit a lot easier and still clamp on well. Very pleased and hope this helps someone else in future.

Attachment 32549

Attachment 32550

Cheers

Andrew

Completely unrelated to your original question, I recently got a pack of gas struts for another project that I made for someone, and now that it has gone out the door, I can't quickly check dimensions. I'm almost sure that the dimensions were very similar to what you have mentioned ? These struts were supplied by the customer and what I can tell you is that he bought them from a well known diy chain (B and Q)

I'm sure that for a pack of 4, he said he paid £7.99 and that included postage! Even if you were to buy them and they were no good you've not spent a fortune.

Just had a quick google https://www.diy.com/departments/dihl...3535612_BQ.prd