Harrison Horizontal/Vertical Mill Restoration

[Mark Davison]

I've got a couple of the £55 2.2kw ones from banggood. I must say I've been pleasantly surprised. One driving a 3hp 2 pole on the lathe and the other driving the 2hp 6 pole on my harrison vertical mill.

 

[Carl Wilson]

Hi Mark, Thanks for your useful comment. I'm definitely leaning towards the lower price range units. I think these will be cost effective and do what I want. I am finding it harder to find a vfd in the lower end of the power rating though. For the feed motor I only need 0.1kw.

Is your Harrison Mill the pure vertical model?

 

[Mark Davison]

There are some 1.5kw versions but they look to be the same physical size and no cheaper. Are you after lower power to get a smaller unit? I cant imagine you'll get cheaper than £55! To set expectations, whilst both mine delivered in about 8 days from china the Corona outbreak is playing havoc, on banggood about 1/2 the items saved in my wish list are now out of stock.

 

[Mark Davison]

Yes, vertical only, with the added benefit that they run standard 100 frame motors and poly v belts.

 

[Carl Wilson]

The feed motor is only 1/8 hp. Therefore I don't need anymore than 0.1 kw to drive it. I appreciate I could use a much higher rated unit, but I will have a 2.2 kW unit driving the main motor, so I want to keep the footprint down for space saving.

 

[Hopefuldave]

Something like (looking at the small, low-power ones)

https://www.ebay.co.uk/itm/Micro-22...hash=item288167efc7:m:m7jb5b86-aKlWu5cS_pQ-Bg

or
https://www.ebay.co.uk/itm/AT1-0750...068404&hash=item5924dd1e9f:g:sPgAAOSwRwxcZRWd

Lots of 'em, not too expensive? (Ni!)

Dave H. (the other one)

 

[Carl Wilson]

Thanks Dave. The second one there looks pretty good as the casing is not too deep. The first one I'm sure would be fine, but I think the first is more likely to fit easily into a cabinet.

 

[Hopefuldave]

I remember one of the Japanese makers (Toshiba? Hitachi?) made one not much bigger than a pair of fag packets stacked, about 150 watts, but I can't find 'em now...

Dave H. (the other one)

 

[Mark Davison]

The second one in Dave's post is the same physical size / casing as the ones I have.

 

[Mark Davison]

**On reflection I think the (2nd) one Dave has linked to above is slightly shallower front to back than mine (below), but it won't let me edit my post.**

Recently I've tended to favour banggood over ebay as they dont pretend to be a UK seller. 90% of the stuff I've ordered arrives with 10 days, and most of that in 8 days. As with everything from china if it is a dud then you are on your own.

Unlike ebay banggood definitely filter their feedback, I'd disregard the stars and read the text as less than 5 stars rarely makes it through the filter and some people will work around that! As I say I've had 2 of these and no problems so far, although if I were to turn either on at anything like full load whilst the gear box oil is cold I can get them to throw an over current error. You simply press reset and off you go again (and let the oil warm up), only happened a couple of times each. This is the link to the one I bought, but the graphics on the case seem to have changed, mine have no branding.

https://banggood.app.link/NgO83eIVx4

Oh, and dont believe it if it tells you it has a brake, I cant get it to function.

 

[Carl Wilson]

Hi chaps and thanks very much for all the quality information.

I'm just about to leave on a plane for work so I won't be able to do anything on the mill project for a while. Save choosing and buying a couple of vfd units to drive the main and feed motors. I'd like to get both tested sooner rather than later. In the main this is to prove my delta re-wiring and ensure all is well after reassembling with new bearings.

Thanks again for the info it will definitely help me choose.

 

[Agroshield]

Oh, and dont believe it if it tells you it has a brake, I cant get it to function.

As I understand it, the braking on a modern VFD is done internally up to a certain level. After that, you need an external braking resistor. Maybe the one you have needs the external resistor for all braking effort.

 

[Carl Wilson]

Yes. The Teco one I have on my lathe uses Dc injection braking. A brake resistor would be huge over kill.

 

[Carl Wilson]

I'm back from the ship now, at long last. I have some time to work on the mill restoration. I've been looking at making a replacement for this part, which is the table lock bolt.

 

[Milkybars]

You got a lump of something nice, Ent24 or something similar.
It's always nice to at least have something to work from !!

 

[Carl Wilson]

I will have a dig through and see what I can find. I might make it from the same material I made the slitting saw arbour from. That was "a bit more than mild steel" as a certain person might say.

 

[Mark Davison]

Mine was bent too, almost as badly as yours. I straightened it as best I could. Whilst it does works, it does just feel like it wants to bend again. I'd second the vote for EN24, you'd just have to remember to undo it before moving the table if it is tougher than the original)

 

[Carl Wilson]

Thanks for that Mark. Nice to get some input from another owner of one of these machines. Also interesting to find that the bending of these lock bolts is perhaps a common issue.

 

[Carl Wilson]

I have got some 316 stainless which I could use, it's not far off EN24t in terms of mechanical properties.

Edit:- Just remembered I have some old green pin shackle pins. They are tempered high tensile steel so should be good for making this part from.

 

[Agroshield]

Mine was bent too, almost as badly as yours.

Is it worth a five-minute investigation to determine if the skinny bit at the top (I think it works out as 5mm from dimensions given) could be made bigger? If you poke a 5mm drill into the hole, it should clear. What of a 5.5mm or 6mm? Sometimes the manufacturer's made parts generously-sized for ease of assembly or speed of production whereas an artisan-fettled item can be made to tighter specs.

A lot of the cause of the bending is the use of a nut (and hence a spanner) to lock it. It is like a split cotter; it needs minimal force as the clamping action is greatly magnified by the pitch of the thread (work out how much angular rotation of the nut is needed to get one thou' movement of the clamp). So on the new one, maybe dispense with the nut and make a dedicated locking handle with no more than a 1 1/2" long stem on it.