Thread: I.M.A. Parva 250 Combination Machine ~1960

A 120mm diameter cutter head should be running around 5000 rpm (surface speed of 1900ish m/min), so if you can provide the diameters of all the parts, it can be reverse engineered from there.

We'll need the size of all 3 V-pulleys, the cutter head, the feed rollers and the number of teeth on the chain sprockets.

That being said, you will NEVER get back your investment; this is a project to do because you want to, not for profit.

OK, I have gotten some more information. I contacted a person in Germany who has this same model machine on eBay. They were super helpful and got back to me with some photos of the motor pulleys from underneath the side cover. They estimate the larger pulley to be around 150mm, the smaller one about 50mm.

The 1st photo shows the larger pulley compared to the feed roller gearing pulley next to it, which I have measured to be 150mm diameter, so there estimate seems accurate. The 2nd photo shows both motor pulleys, with the smaller one being around 1/3 the size.
DSC00012[1150].jpgDSC00011[1151].jpg

I have also measured the rollers, cutter, gears and pulleys.

The cutter head has 2 blades, and is 85mm diameter.
The pulley attached to the main shaft is 66mm OD (unsure of where to measure on a vee pulley).

The rollers are 45mm diameter. These are attached to 29 tooth sprockets.
The drive sprocket at the bottom of the chain loop is 10 tooth. This sprockets axle has a 80 tooth gear attached on it inside the housing.
The 80 tooth gear runs against a 20 tooth gear that is connected to the lower vee-pulley (marked 'B' on my photo above).

I found some online pulley and compound gear calculators, and entered the above dimensions. The motors I have are all rated at 2850rpm (though I am guessing they are 'original').

The cutter head, when using a 66mm small pulley on the cutter, and a 150mm pulley on the motor, comes out as around 6500 rpm. No idea if this is an appropriate speed for a 85mm diameter head.

If the motor pulley for the rollers is 50mm, then the rollers seem to come out at 35:1, so around 80rpm or 11m/minute (once again, I have no idea if this is a realistic figure or not).


@elanjacobs, hope this all means something to you. As for my investment, the machine cost me $300, so even if I have to buy a new motor, and some pulleys/belts, I think it's an ok price for a 10 inch jointer/planer. I just wasn't sure if by 'modifying' the machine I wasn't ruining any value it might have to a collector

I just spent over an hour writing an update, with photos, diagrams and measurements...only to return later to find that the post has vanished >.<

Basically, as far as I can tell from using online gear/pulley calculators and some sizing I got from a guy in Germany, the cutter head (which is only 85mm OD) should be spinning at around 6500 rpm. I think this comes out at around 1700 m/min.

The rollers are 45mm OD, and would be moving at around 80 rpm, or 11 m/minute.

I have no idea if these results are reasonable, as I can't find many numbers for 10" jointer/planers to compare.

@elanjacobs My investment is only $300 so far, which I felt wasn't to bad for a 10" jointer/thicknesser, I just didn't want to cut up a machine that might be worth more than that to the right someone.

Those numbers sound about right.

I more meant you won't get back the investment of money and time in restoring it, especially since you'll need to either somehow source parts or have them made. You might get $3k if you got it running; I'd guess at least 1k for a motor, pulleys and belts, what do you value your time at?