Rapidor hacksaw

years. (nothing Adrian
I have a Rapidor Major in very good condition, and what you describe sounds similar to my saw.
On the Major the blade is angled with respect to the motion of the slide, so that the cutting pressure is maintained as the blade moves forwards. i.e. the frame tends to lift as it moves forward and the blade rides over the work. On the return stroke the descent of the frame is delayed by the action of the dashpot, so the blade is held out of cut. The knurled rod in the dashpot presses against the piston plate, and allows adjustment of the damping rate to suit the speed of cutting. There is no mechanical link between the drive mechanism and the dashpot (though there is a simple prop to hold the frame lifted clear when not in use).
The vice on my Major works exactly as you describe.
Hope this helps
Mike

OK, I can see how that would work. I presume the dashpot should have oil in it, not just air - if so, how thick should it be ?
However, there's certainly a line of less muck on the edge of the cam. I'm glad I haven't got to build a master cylinder for it, but I wonder what's caused it ? Nothing else appears to rub there, and the boss below doesn't have any obvious function (there are other holes for mounting and draining). Maybe a cam-operated suds pump ?
Yes, I've got the prop too.
Thanks !
-adrian

We also have a 14" blade Rapidor, we can do some pic's of specific items if you need them. Our vice also does that!
Peter -- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk

The one at the bottom of this page ? :-)
That's pretty well identical, though I wasn't sure of the size. Except yours has a weight, stand, motor, and has had a lot more elbow grease applied !
I think Mike's sorted out my biggest problem, but a pic of the top of the dashpot would still be interesting, thanks. And do you have a boss (or even just a hole) in the tray directly underneath the cam / flywheel ?
-adrian

Mine has such a hole. Since it had a pipe fitting screwed into it I assumed it to be the coolant drain. Whatever; that's what it gets used for.. hth

Yup, that's the one.
Mad Mick Mills did the work, I bought it from him after he had been over it and sorted it out.
See Roly's reply, but I will check mine as well tonight and take a pic.
Peter
Peter -- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk

Adrian
I use ordinary 30 grade oil in the dashpot, and it seems to give a sensible range of damping adjustment.
-can't help on the cam you mention. I guess you must have a different model of saw to mine. My suds pump is buried in the base of the unit, and is chain driven
Mike

Possibly not the same as mine, then - the base casting has a wall just behind the dashpot, and the hole I mean is behind that, only a few inches from the back. This area would tend to collect spilled oil from the mechanism, so is best kept apart from the suds. The coolant couldn't drain to there without also flowing onto the floor. The boss might well be part of a pipe fitting, but I haven't taken it apart yet.
There is, however, another hole just in front of the dashpot : this would drain fine. But on my model, it doesn't have any sort of fitting.
This machine looks as though it was n production for a long while - there must be a lot of variations about, especially in such things as motor mount and coolant pumps.
-adrian

Hello Adrian,
The boss in the base under the cam is for a suds pump. Mine is currently siezed...
I can take some pictures of it if you like - let me know...
Cheers,
Jez.
jez[AT]jez[HYPHEN]nikki[DOT]net

Yes please ! Or even just a written description - I can imagine a spring plunger and valve arrangement but approximate dimensions would be interesting.
-adrian

I was given a machine vice which had the same problem - there was a slot on the threaded rod, just inside the casing, which I think should have had a circlip on it (or something). I couldn't get a circlip on (not enough clearance for pliers) so I wrapped a couple of turns of thin wire into the groove. It's worked OK for a couple of years now.

Hi. I found your reply very useful. I also have aquire one of these lovely old machines. Forgive me for being thick, are you saying that the saw cuts on the forward stroke? Also, just below the top edge of the dash pot, there is a bent and mangled bolt in mine. Any idea of its function? Finally, any clue as to where I might fingers a parts diagram/manual? Thanks in anticipation. Stuart York.

Hi. I found your reply very useful. I also have aquire one of these lovely old machines. Forgive me for being thick, are you saying that the saw cuts on the forward stroke? Also, just below the top edge of the dash pot, there is a bent and mangled bolt in mine. Any idea of its function? Finally, any clue as to where I might fingers a parts diagram/manual? Thanks in anticipation. Stuart York.

I wonder if the information on the pages starting at:

are of any help to you?
Alan

Hi. Thanks Alan, the site you mention has details of the Rapidor saw, they are asking a lot of money, and I'm reluctant to purchase as there's no real indication of the quality you get for your money. I was hoping a fellow enthusiastic rebuild had a parts list/ diagram they might share. Thanks for taking the time to reply. Stuart

Hi. Thanks Alan, the site you mention has details of the Rapidor saw, they are asking a lot of money, and I'm reluctant to purchase as there's no real indication of the quality you get for your money. I was hoping a fellow enthusiastic rebuild had a parts list/ diagram they might share. Thanks for taking the time to reply. Stuart

Stuart
As I explained in my original message, when properly adjusted the damper holds the blade out of cut on the back stroke. The blade must therefore be set in the frame so that the teeth cut on the forward stroke.
HTH
Mike

Hacksaws normally do.
I remember my school metal work teacher having a funny demo to teach this, along with using an initial 'back stroke' to mark the line of cut.
The Japanese use some pull saws in woodwork but I've not seen them in metal saws.
Jigsaw blades cut on the up stroke but the blade is only supported at one end.

Hi Adrian fellow Rapidor restorer. I have just finished what I believe is a 1952 Rapidor Manchester Hacksaw with the same similar issues your having. I think the vice mechanism is how you see it. Mine is exactly the same. No pin to hold it from coming out of the release jaw, but at the very back of the lose jaw on mine there is a screw hole but whether that held a plate or somethings to be guided on the threaded bar. I don't know, there is no sign of it on the machine when I was taking it apart. The piston you described is exactly the same as mine. What the little bar does on the side Once again I do not know. The only thing I can think of is that it could of operated a water cooling pump. On the older versions its got a lit cover on it and shaft is free to move through it but no sign of a water pump. The code number how ever I think mine is 3mx or something but after that all in the same line its got 1952 . So 3MX1952 and that's all I have to go on with regards to its age. This machine looks great. I have painted it with a dark green Japlin colour and a red wheel in memory of Frank Hornby, Meccano. The main Cam is perfect with no ware on it so again I cant comment on that. The problems I have had is the motor was Three phase so I have fitted it with a single now. I have one last problem and that the release handle with the looking handle I am not sure how the spring mechanism works I cant find any literature on or with regards to the machine specification at all. There's is lots of lovely Youtube videos on seeing them operational which is great, but not much use when you are restoring them. Only other issue it heavy ha ha. If you know of any literature with regards to the spring mechanisms I would greatly appreciate it. Good luck Adrian hope it all works well.