When to use a spindle top support on a spindle moulder?

[heimlaga]

I don't have a spindle top support for my spindle moulder but I started thinking about when it should be used. We never used one in vocational school and I have notised that some newer spindle moulders aren't even intended to use one. However there is a lot of stress on a 30 mm spindle when running large diametre tennoning heads.

Do you have any oppinons on when a spindle top support is needed?

 

[custard]

The specifications covering your spindle moulder will state the maximum safe size for tooling. It's not only about the 30mm spindle itself, it's also about the spindle bearing arrangement below the table surface. If it's a reasonable quality machine and the tooling is within the machine's specifications I wouldn't worry about it unless you're seeing inaccuracies in the work that can only be a result of the spindle shaft flexing.

 

[blackrodd]

The specifications covering your spindle moulder will state the maximum safe size for tooling. It's not only about the 30mm spindle itself, it's also about the spindle bearing arrangement below the table surface. If it's a reasonable quality machine and the tooling is within the machine's specifications I wouldn't worry about it unless you're seeing inaccuracies in the work that can only be a result of the spindle shaft flexing.

+1, As above. If you have the tooling already, you will need to know what machine it is designed for.
If not, suppliers like omas and the like will be able to advise, as in block size, rpm, feed speed etc.
If you have the tooling, The fact that it is 30mm (and not top hatted) will mean the shafting matches ok, but you will be best advised to discover the recommended rpm and use the spindle moulder manufacturers approved tenon carriage, as very unpleasant things happen when you hit a knot on end grain especially on a big scribe.
Which is no time to discover how flimsy a home made ply box can be, with all due respect.
I worked in a door factory for some time and used single ended tenoners, some wedge making machines, and also some haunching machinery, most wood working machinery except for the double ended tenoner and the double headed spindle moulder.
Apart from "knot shrapnel" unscathed, probably from my teachers constant reminders on safety.
Be safe. Regards Rodders

 

[heimlaga]

Thanks....but I am 50 years late trying to get any specifications on my machines.
My combination machine was manufactured in 1957 and the model went out of production in the 1970-ies. The manufacturer knows nothing about it anymore. I have cut smallish tennons with it for several years without a top support but I would feel safer if I know that I am within the limits for that practice and once I would like to use the bigger heads as well.
My newly bought separate spindle moulder probably went out of production in the 1940-ies and the manufacturer went out of business in 1978.

All my tooling had been bought secondhand but most are fairly modern. No square heads nor slip kniver nor any other type of knives held by friction alone. Everything in decent condition. Almost all have the maximum allowed RPM stamped on the body but nothing said about the need for spindle top supports. All the big heads which could be critical have 30 mm holes but some smaller heads require top hats.

I have the proper tennon carriages for both machines. Super rigid chunks of cast iron. I would never dare to use any home made wooden contraptions.

So...the basic question is still pretty mych unanswered........
Let's assume that the machines are built strong enough. Those big ball bearings and heavy cast iron frames look like if they were built to handle any tooling that has ever existed. The old spindles themselves seem like the most uncertain factor as the quality of steel shafting wasn't as good then as it is now according to a relative who was a shipbuilding civil engineer back in those days. However some of the spindles are replacements made from modern high quality shafting.
What would be a typical maximum size of tooling run on a 30 mm spindle without a top support?

 

[RobinBHM]

Ive run 320mm dia tooling on a modern italian spindle moulder with no top support. To be honest I have never come across a machine with top bearing options. I now use the same tooling on a VG 4 head tenoner. The last head is a vertical shaft and is designed to take large blocks.

The only time I have come across shaft supports is on heavy duty 4 siders, such as Weinig and the outside bearing is used to stop end play for increased quality of finish more than strength. These large machines also use hydro fix locks which are hydraulic locking rather than nut and spanner.

 

[blackrodd]

I have not used a top support spindle moulder. much less seen one used.
If you look at a dedicated tenoner in action, you can see the cutter set up including the shoulder cutters, designed to cut the cross grain fibres cleanly, top and bottom, difficult to replicate on the spindle.
Tenon blocks are normally used, spaced, and set up for working at the normal, low as possible situation.
Personally, I would not use, or be near any blocks working at the top of the shafting, if that is the reasoning for you're top support query.
As you say you have the maximum rpm stated on the block you intend using, then stick to those guide lines.
I would not use any top hats as the blocks are for a bigger shaft machine and are therefor quite possibly too heavy and unsuitable.
Sorry for appearing negative to you're query, but I have found it is better to be cautious than sorry.
You're machinery sounds really excellent, from when weight was quality, and 1 good machine would outlast several users
Regards Rodders

 

[heimlaga]

Thanks. It sounds like the kind of tennoning that I have dome so far vas safe without it...... but I have never dared to use the big cutters.

The reason for my query is that my old schoolbook from vicational school states that when tennoning with large diameter cutters one must use a spindle top support. Then there is a picture of a round pillar with a substantial cast iron arm. At the end of the arm is a bearing that fits over the thin end of the spindle. I have seen supports like that on old machines advertised for sale and it was offered as an optional extra with my combination machine according to the old parts list.
My separate spindle moulder has apparently had a setup like this in the past. The top of the spindle has a thin top end bearing surface on it above the threads and there are two holes where the pillar was once bolted down. The seller claimed that those holes had likely not held a feedwork as they were there before they bought their first feedwork.

My tennon carriages are bolted onto the tables in the old style. Not the flush type sliding tables of today. This means that the cutters end up some 30 mm further up the spindle than on a modern machine with a sliding table.

 

[blackrodd]

You're spindle Sounds really strong and substantial, is it finnish in make, or imported?
Regards Rodders

 

[heimlaga]

My combination machine is a Stenberg KEV 600. It has a 5hp table saw with 400mm blade and a 60 cm wide planer/thicknesser and a 3hp spindle moulder all on the same frame. Manufactured in Stockholm in Sweden in 1957. I rebuilt it completely a few years ago.

My separate spindle moulder which is still not in use awaiting a bigger workshop is a Jonsered FM-C. Made in Jonsered in south western Sweden. This model was originally designed to be line shaft driven but mine is one of those that got a very substantial motor mount fitted at the factory.