A wood thing

[shedhappens]

I reckon showing an unfinished project is a bit like answering the door without your undies on,
anyway here it is in all of it's nakedness.

It started off as me not wanting to push a router along 76 mtrs of hardwood handrail that I have to do.
I want to put a radius on the two top edges and route out the bottom to fit over the
50 x 5 mm flat steel on the balustrade, I still have 2 more balustrade's to make first tho.

The thing is mostly made of what I had at hand, I don't think I have spent more than 100 bucks so far but
have intermittently spent a bit of time on it. There is still a few unfinished bits and pieces like the
dust control, pulley's, pressure wheels to keep the timber against the rollers ect ect

It has an old zero turn ride on mower hydrostatic wheel motor for the feed and that is driven by
a 1 hp 3 phase motor, I reckon that part should work ok and will have pretty good feed speed control
if the rollers don't slip on the timber.

The part that I am extremely suss about is the motor for the spindle, (and the spindle rigidity)
I'm not too happy with the mounting or the position of it and I don't think that it will have the
grunt needed even at a slow feed, so I am thinking about scrapping that motor completely and
start a fresh approach with another motor and spindle mounting.

This motor is a 2800 rpm 1/2 hp 2 pole, the spindle spins at 5000 rpm, measured with a tach,
that ratio was just guess on my part.

So........firstly, will that motor do the trick ?

If not, what size motor will I need and what RPM should the spindle have ?

If anyone reckons any other part of the thing is stooopid let me know, I won't cry

[Jekyll and Hyde]

I know nothing about wood, but I would have thought the spindle speed was pretty low by router standards, and this post seems to agree with me https://www.woodworkforums.com/f13/ro...t-woods-22475/

I take you don't own a router, given that you've gone to the trouble of making up a spindle, otherwise I would have said why not just mount a proper router on it. Any of your mates got one they don't mind lending for a little while? I take it this setup is probably a single use type deal anyway...

[malb]

I am guessing that the roundover bit you have is about 3/4in cutting radius, so probably about 2 +inch diameter. To run a bit that size, woodies would be aiming for at least two horsepower at about 12-15,000 RPM direct drive, and they would do the job in at least 3 passes, rather than a single heavy one

A half horse 2800RPM motor effectively geared up 2:1 to get to about 5K would have very limited torque and would most likely stall even on a light cut. Early trim routers were in that order of power at 20-25,000RPM and limited to 1/4in diameter bits and still loaded down severly.

The job is normally done with a spindle moulder running a cutter in the 6-8 inch range, typically around 6-10HP at about 6000RPM.

[GSRocket]

I admire the effort you have gone to build the jig.
I have hand pushed a router probably a thousand miles in my life.
A router bit that size (50mmD) I reckon about 10,000 revs would be the minimum depending on the wood.
To get the best finish and also easiest on the router is to make two passes
and then the 3rd pass only takes off a smidgeon at max revs, 20,000 RPM if you've got the revs.
If it was me.... I would simply fix a standard router in there then it would be very easy to adjust the height and revs for each pass.
Another thing......You will need some device to keep downward pressure on the wood. If you were to do it by hand and slide the router,
this would normally compensate for any curves in the wood and also varying thicknesses but you wont have that advantage with your setup,
so it might be advantageous to thickness the wood first.

[Ueee]

I think the guys have said it pretty well, your half horse won't even go close.....I have a spindle molder with a high speed router spindle. It trundles along at 12500rpm with 4 horses behind it and i can slow it down if i push it hard. Really you need a spindle molder and power feed unit......I'd happily do it if you were closer.

[shedhappens]

Thanks fella's, yeah I thought I was dreaming with the 1/2 hp motor.

I'm pretty sure my feed rollers will work, I have yet to make the gizmo to put the pressure on the timber, they will be adjustable and spring loaded, and the kids have grown out of their roller blades so I am going to put the wheels to a good use there.

I'm not gunna buy a router, I had thought of that but I really are sick of wood now and don't intend to have wood anywhere near my shed once I have finished the house.

I have a 5 hp
(I think)3 phase that was a donation from RayG, thanks again Ray, so I might work out something with that.

Ueee 12500 RPM is fair hooting along, what can you tell me about the spindle shaft on yours ?

What diameter is it and do you think I would need to use something like 4140 ? I might make a combination belt/gearbox drive, I will have to see what gears I have and that might determine the spindle shaft size, I suppose it would be best to keep it short and chunky.

john

[Ueee]

Ueee 12500 RPM is fair hooting along, what can you tell me about the spindle shaft on yours ?

What diameter is it and do you think I would need to use something like 4140 ? I might make a combination belt/gearbox drive, I will have to see what gears I have and that might determine the spindle shaft size, I suppose it would be best to keep it short and chunky.

john

It sure is, used as a spindle molder it does 3000,4500 and 6000 (i think), it is a whole different shaft. Its a multi v belt driven thing, pulley machined into the shaft between the bearings. The pulley on the router spindle would only be 3/4" dia. I would be sure the whole thing is not just MS, being an Austrian machine it is very nicely made, ground finish etc. 7 years ago when i bought the machine the extra spindle (you only got either a router or spindle molder with it) was $800 or so. I can take a pic of them tomorrow if you like. The router spindle just has an er20 collett on the end.

[shedhappens]

Thanks Ueee

That shaft sounds interesting ?

I suppose the brgs are not something like a 6204 ?

I better find some info on brgs

[Ueee]

Thanks Ueee

That shaft sounds interesting ?

I suppose the brgs are not something like a 6204 ?

I better find some info on brgs

I will let you know, i would say they are a deep groove, about 3" in OD

[Ueee]

Hi John,
Sorry i forgot about this....but here is a pic of the router spindle. Unfortunately i cannot see what the bearings are without pulling it to bits.
The other thought i had, is what sort of mill do you have? Now machining timber on a metal machine is a pretty big sin, but if you cover everything up well and use a vac or dust collector you shouldn't get any dust on the ways. I know the top speed of the mill may be limited to 2500rpm but you will still get a very good finish if the feed is kept down and you have no risk of burns. Plus you are using a nice rigid spindle that you don't really have to do anything too.

[shedhappens]

Thanks Ueee, you shouldn't have pulled it apart tho

I am going to make a new spindle assembly, I have bought 2 x 6305 bearings, 25mm shaft size, they have a limiting speed of 11000 rpm with grease or 13000rpm in oil.

I'm thinking seriously about using my 9" Makita angle grinder to drive the spindle,
6600rpm, 2200 watts, I'll make a couple of steel pulleys, that's if I can't find any in a box somewhere, and have roughly a 1 to 1.5 ratio, so roughly 10000rpm and that will give me roughly 2 hp at the cutter.

Will be interesting to see how the chinese makita handle's that ?


hey hey, did you see those rough words ?

[Combustor]

Had a Jap Makita 5" angle grinder for a while, OK but noisy in the gears and vibrated a bit. When it died the only replacement available here at short notice was a Chinese one, so I bit my lip and paid the money. Best grinder I have owned, the old 9" is gathering dust. Have worked the Chinese Mak hard for years and it still comes back for more. Can only assume the Japs still exercise their quality control in China. Combustor.

[shedhappens]

I got back to doing a bit of work on the wood thing, just before Chrisy I gave it a jam job with some machinery gray from the $2 shop, and then on and off over the past week I started to play with mark 2 of the spindle set up.

I have fitted a linear rail setup on it to mount the grinder and spindle on, this will make the cutter adjustment (Y axis) easy and I think that if I put a handle on the spindle belt/pulley guard then it will probably be easy to check out timber with it.

I found an old hydraulic pump pulley, bored it out and faced it off to fit on the grinder, it spins over nicely with no vibration.

Then I made a new spindle shaft to suit the new bearings, dunno what type of steel ? Rusty bit of bar I called it, anyway then I had a hunt around for that short piece of 80mm bar that I had seen a few years ago, well I found it, but it seems to have shrunk over that time to 75 mm diameter.
Well I had a slight dilemma here, if I now wanted 80mm dia bar I would have to get in the bloody car and drive somewhere to get it, and I bloody well hate driving over that bridge out of town

So I made a 75 mm pulley, now the gearing is 130mm ÷ 75mm = 1.73 x 6600 = 11440 rpm.

So 11440 rpm at the spindle that has bearings good for 11000 rpm, I thought I might see how that goes but then I started thinking about the belt speed.

3.14 (pi) x .130 dia = .4082 (circumference) x 6600 RPM = 2694.12 Mtrs per min ÷ 60 seconds
= 44.902 Mtrs/sec

A bit of a search on googz tells me that 40 mtrs/sec is the maximum speed for an A section belt,
so I have 400 revs more than recommended for the the brgs, and close enough to 5 mtrs/sec to fast for the belt speed. eeek

So what do you guys reckon ?
Is there a high speed belt that will do the job, and then I take a punt that the brgs will handle a few extra rev's ?
Do I stop being slack and make a smaller pulley to go on the grinder ?
I know that according to the woodies REV'S are the go, but in this case at what risk ?

john

p.s I would be great full if someone checked my math, tiz not really one of my strong points

[Michael G]

The recommended speed for a bearing is based on it's life. You can run them faster but the probability of getting the million cycles (revs) that the bearing is designed around is reduced. There is a formula to calculate it but with the price and reliability of modern bearings I don't think too many people bother.
For V belts, power transmission is restricted by belt speed - too fast and the belt will slip more.
In both cases the over speed thing means that things are not working optimally. It may mean that you have to replace things a little more often than you otherwise would. As this is for a particular job it probably won't matter.
(And of course things will be guarded so that if something did go bang, no one would suffer right?)

Michael

[shedhappens]

Thanks Micheal, I reckon I might try and find a belt that is suited to the higher speeds, and I reckon the bearings will yell at me before they do anything horrible