Another Rapidor rebuild

[Fazerruss]

Thought I'd share a few pics. I'm refurbishing an old Rapidor Major power hacksaw....

When I got it the thing looked like it had fallen in a big bucket of blue paint!

Still not finished yet though. Next job is to sort out the blade holders (bottom pic) The threads in the holes that the grub screw fit into are both stripped. Problem is they are blind holes so I can't easily tap to next size up unless I buy a specific tap or grind one down.

 

[brewdexta]

Very nice, looks a proper job

 

[shed or dead]

I have one also, it's been sitting in a corner for months until I picked up a cheap 3ph 3HP motor off ebay on Tuesday.

Fitted the motor, started it up, and the whole thing started heading for the door! Today I bought some ground anchor bolts but haven't fitted them yet, not sure where it should live to be useful but not in the way.

A problem I've been having is with the saw going up rather than down, but I'm hoping this is just down to it's dancing around. I changed the rotation of the motor but the same thing happened. What way should the pulley wheel on the saw be turning? Thanks.

 

[brightspark]

I have one also, it's been sitting in a corner for months until I picked up a cheap 3ph 3HP motor off ebay on Tuesday.

Fitted the motor, started it up, and the whole thing started heading for the door! Today I bought some ground anchor bolts but haven't fitted them yet, not sure where it should live to be useful but not in the way.

A problem I've been having is with the saw going up rather than down, but I'm hoping this is just down to it's dancing around. I changed the rotation of the motor but the same thing happened. What way should the pulley wheel on the saw be turning? Thanks.

clockwise looking from the end of shaft gawd 3hp is well ott

 

[shed or dead]

And as BrewDexta says, you have indeed made a very nice job of yours. Mine will need to start behaving before I even consider a resto job on it.

 

[Fazerruss]

Not had this running yet because it was 3 phase and i'm converting it to single. As far as I know the crank should do an over arm motion like a cricketer and the blade set to cut on return stroke.

 

[shed or dead]

Thanks Brightspark. I also have a 1HP motor I got from the same guy, do you think that might calm it down a touch, or do I need something in-between?

The 3HP was from a 160L Clarke industrial compressor that the chap was scrapping because 'it ain't working right'. I gave him 20 quid for it, then drained 6years of water and emulsion as we lifted it into the back of my corsa. I don't wish to hijack so I'll start a new thread when I get round to looking at it proper.

 

[brightspark]

have u checked the speed of it.mine runs about 80rpm at the crank a 1hp is well enough mines got a half hp fitted. if yours is a bit lively it may be running 2 fast

 

[MattF]

Not had this running yet because it was 3 phase and i'm converting it to single. As far as I know the crank should do an over arm motion like a cricketer and the blade set to cut on return stroke.

Blade should cut on the forward stroke, according to an original Herbert tag I saw on one machine ages ago. Think I have a photo of it knocking about somewhere. I'll post it if I can dig it out.

You've made a lovely job of that btw. Looks very nice.

 

[shed or dead]

I think the 3HP is 2800 with 100mm pulley onto standard Rapidor transfer pulley. No idea at the crank though.

Any ideas for a coolant pump? I'd prefer mechanical as I'm not keen on 3ph with liquid, and I'm sure I read not to bring 1ph near to 3ph.

Thanks

 

[shed or dead]

Thanks Fazerrus and MattF.

 

[brightspark]

I think the 3HP is 2800 with 100mm pulley onto standard Rapidor transfer pulley. No idea at the crank though.

Any ideas for a coolant pump? I'd prefer mechanical as I'm not keen on 3ph with liquid, and I'm sure I read not to bring 1ph near to 3ph.

Thanks

jeesus the motor should be 1400 rpm it will be out the door like the clappers and self detruct at that speed nothing wrong using a 3 phase pump. if u have single phase sockets near each other @ 230 v its not practice to have them on diffrent phases as u can get 415 v touching between them

 

[MattF]

This is the tag.

I based the assumption of direction on the fact that most top covers on the Rapidors seem to have the hole in the top cover towards the rear, the opposite way round to yours, though if that cover was on the same way as yours, then it would obviously indicate a backwards cutting stroke.

I think the 3HP is 2800 with 100mm pulley onto standard Rapidor transfer pulley. No idea at the crank though.

Think you want a 14** RPM unit on there.

Any ideas for a coolant pump? I'd prefer mechanical as I'm not keen on 3ph with liquid, and I'm sure I read not to bring 1ph near to 3ph.

Is the original pump not on there? It sits atop the large pulley assembly inside the base.

 

[zzr1200]

2800 rpm...

I've heard of chainsaw racing but never power hacksaw racing.....


As stated above, should be a 1400 rpm motor...


I only fitted a half horsepower motor to mine, its cut 1" thick flat strip happily.

 

[brewdexta]

me too - 1400rpm 0.37KW, the belts slipped before the motor struggled, a bit of belt dressing sorted that and now it cuts box and solid nicely.

 

[wheresmejumper]

i also thought that the front vise was fixed to support the piece on the forward cutting stroke

 

[brightspark]

2800 rpm...

I've heard of chainsaw racing but never power hacksaw racing.....


As stated above, should be a 1400 rpm motor...


I only fitted a half horsepower motor to mine, its cut 1" thick flat strip happily.

lol ive cut 4inch round solid bars with mine and pressed down on the frame to make it cut quicker it warms the motor just a bit

 

[Fazerruss]

This is the tag.

I based the assumption of direction on the fact that most top covers on the Rapidors seem to have the hole in the top cover towards the rear, the opposite way round to yours, though if that cover was on the same way as yours, then it would obviously indicate a backwards cutting stroke.



Think you want a 14** RPM unit on there.




Is the original pump not on there? It sits atop the large pulley assembly inside the base.

When I started the rebuild I put it the way you mention rather than like in the top blue pic. It seems to fit better giving less play in the slides and also the shape of the casting suggests it goes that way around. I think a previous owner stripped it and put it back wrong.

There's no pump on mine so ill see what its like for now.

 

[brightspark]

ive been using an oil can with white water for the blade or a drop of rocol cutting compound thinned with white spirit it cuts much faster and does make the blades last longer .another thing i do is put an inch block in the vice after the blade has been cutting a lot of small material it moves the job to a newer piece of the blade and lasts a lot longer instead of wearing one point out

 

[MattF]

When I started the rebuild I put it the way you mention rather than like in the top blue pic. It seems to fit better giving less play in the slides and also the shape of the casting suggests it goes that way around. I think a previous owner stripped it and put it back wrong.

I did the same with mine too, checking it both ways and going with the best fit. It ended up going back on same way as it came off.

There's no pump on mine so ill see what its like for now.

I'm personally not planning on refitting mine, but rather going with the manual method brightspark uses. In all honesty it's a naff original coolant flow design on the Majors, with the suds pump being fed directly from the bed. It's just begging for swarf to clag the pump. This pump was jammed solid when I got it. This is the factory setup, incase you you find something which'll fit.