Thread: Problem With a Hafco HM-46 Mill/Drill.

Hi Justin,

Welcome to the forum.

Sound like a problem with the rack and pinion drive on the quill, you could pull it apart and see what's causing it. If it's still under warrantee, you have a good claim for a replacement.


I don't have a HM46, but the quill drive rack and pinion is probably similar to the HM52.

Very rarely do I machine with the quill unlocked, maybe if just drilling, but as a general rule on the HM52 I use the knee for height.

On the HM46, I would think you would machine with the quill locked and use the rack and pinion head raise/lower to set the height.

Do you have a DRO?

Regards
Ray

Hi Justin, and welcome to the forum.
I have heard of that problem before so it's not uncommon. I would say the guys on the Yahoo Mill Drill group would be able to help as there are a lot of members with the same machines.
I also have a HM52 like Ray and agree they are almost identical in the quill down feed area.
I would first take off the complete down feed/ fine feed cast box on the side of the head (Make sure you lock the quill lock before doing this). Clean it all out, put it back together and put it aside with out grease. Then slide out the gear shaft, unlock the quill and slide the quill out and clean both it and the housing. The gear shaft may have 1 or 2 screws that hold it in position from underneath.
After everything is clean reassemble the quill into the head and the gear shaft and check it for binding. If everything seem OK their it might be the worm and gear in the housing binding.
I had to go through mine and clean and fix everything and it now works nice. I haven't finished righting up about it as I promised other members here I would, I will see what I can do over the next few days and it might help you also.

Dave

Thankyou for the replies every little bit helps.

I always lock the spindle after making an adjustment to ensure that what ever I adjust it too stays correct.

I can raise and lower the entire head like a knee mill (sort of) but the adjustment is not very fine and the actual arm to adjust is on the column.

Also there is no measurement so I would have to use a dial indicator to know how much I moved it.

Sadly no DRO but a DRO would solve the problem in the sense that I would not have to use the graduations on the quill.

It's my "understanding" that on these mills the quill is your fine feed?

I may have got that wrong?

Once again thanks for your input.

Cheers

Justin

Hi Justin and welcome to the forum.

I have an almost identical mill to yours, a DM45 bought from Standaco. The problem with quill feed you are experiencing is very common with this group of mills and is the main reason I installed a digital indicator on the quill as a priority.

I have posted how I did that.

I haven't taken mine apart yet, but it is on the "to do" list but too many items on the "honey do" list atm.

Originally Posted by Jarh73

Sadly no DRO but a DRO would solve the problem in the sense that I would not have to use the graduations on the quill.

It's my "understanding" that on these mills the quill is your fine feed?

I may have got that wrong?

Once again thanks for your input.

Cheers

Justin

Hi,
Not sure about down your way, but Aldi stores up here have the digital vernier on sale this week for $19.99 and they are available through ebay for around that price as well.
This will not fix your problem because if you have to plunge into a job a certain depth, it could slip and go more, so I recommend you take it apart, clean it and have a look to see what the problem is.

The quill has both coarse feed and a fine feed. The 3 spoke handle on the side of the head is the coarse feed and the small hand wheel facing the front is the fine feed.
When you wind the head up the column it is called raising the head.
When milling try to keep your quill up/in as far as possible because it will be more rigid. When you use the quill to feed into a job, only come down/out around 25-30mm (unless really necessary to reach into a job) otherwise move the head down so you don't have to extend it further.

Dave

Originally Posted by Dave J

Hi,
Not sure about down your way, but Aldi stores up here have the digital vernier on sale this week for $19.99 and they are available through ebay for around that price as well.
This will not fix your problem because if you have to plunge into a job a certain depth, it could slip and go more, so I recommend you take it apart, clean it and have a look to see what the problem is.

The quill has both coarse feed and a fine feed. The 3 spoke handle on the side of the head is the coarse feed and the small hand wheel facing the front is the fine feed.
When you wind the head up the column it is called raising the head.
When milling try to keep your quill up/in as far as possible because it will be more rigid. When you use the quill to feed into a job, only come down/out around 25-30mm (unless really necessary to reach into a job) otherwise move the head down so you don't have to extend it further.

Dave

Thanks Dave.

I try to keep the quill in as far as possible at all times but at at about 8mm out there is a real problem. If i move the quil out even the smallest amount it literally jumps down 0.6mm all by itself. So if you wanted to do a finishing cut and take of 0.1mm you end up taking off 0.6mm plus.

Working out of that zone there are times when you wind the quill and get no movement whatsoever.

I have just spoken to the supplier and they will allow me to actually do some milling on a display machine and test how well the quill actually works. If display machine works acceptably then they will swap over.

Fingers crossed!

Just on another note when you wind the hand/coarse feed all the way down it actually stays down and gets progressively it wont return and gets stiffer and stiffer beyond what i though the return spring would cause.

Cheers

Justin

Originally Posted by Dave J

Hi,
Not sure about down your way, but Aldi stores up here have the digital vernier on sale this week for $19.99 and they are available through ebay for around that price as well.
This will not fix your problem because if you have to plunge into a job a certain depth, it could slip and go more, so I recommend you take it apart, clean it and have a look to see what the problem is.

The quill has both coarse feed and a fine feed. The 3 spoke handle on the side of the head is the coarse feed and the small hand wheel facing the front is the fine feed.
When you wind the head up the column it is called raising the head.
When milling try to keep your quill up/in as far as possible because it will be more rigid. When you use the quill to feed into a job, only come down/out around 25-30mm (unless really necessary to reach into a job) otherwise move the head down so you don't have to extend it further.

Dave

Hi Dave,
I have the same mill/drill SM 45 from assett, It was my first ever mill (that now only gets used as a drill) I don't have any problems at all with it, and accuracy is spot on.
The reason I am writing is I always like reading your posts as I learn something new every time. I never over the years considered raising and lowering the knee or head and not using the quill more than 30mm or so.
Thanks again Matt

Justin,
If the quill gets tighter as it goes down that is a good thing because there is room for wear.
It will take about 4 hours to dismantle and clean the quill and down feed and I think it would be worth while. It will also let you see what is inside and how it works.
The return spring is on the left hand side of the head and will need to be released before taking the gear and shaft out.
On mine there is a screw from underneath holding it from rotating. To undo it you lock up the quill put a glove on your left hand to hold the spring unit while you undo the screw. When putting it back there is a few holes around the outside of the unit to put a screw driver or allen key in so you can wind it up to put some tension on it.

Matt
Thanks for that, I have been slack lately and not doing any right ups.
It is best to keep the quill inside the head casting as much as possible to keep it rigid. Between 30mm and half extended is actually noticeable in the finish on the job.

Dave

Originally Posted by Dave J

Justin,
If the quill gets tighter as it goes down that is a good thing because there is room for wear.
It will take about 4 hours to dismantle and clean the quill and down feed and I think it would be worth while. It will also let you see what is inside and how it works.
The return spring is on the left hand side of the head and will need to be released before taking the gear and shaft out.
On mine there is a screw from underneath holding it from rotating. To undo it you lock up the quill put a glove on your left hand to hold the spring unit while you undo the screw. When putting it back there is a few holes around the outside of the unit to put a screw driver or allen key in so you can wind it up to put some tension on it.

Dave

Thanks Dave.

What I will do is have a play in the shop on Saturday and see how that machine performs. Then tell them i need time to make a decision.

So on Sunday I'll pull mine apart properly and see if i can find the problem.

My gut feeling is that there is something wrong with the mesh of the rack and pinion but will explore all avenues.

Cheers

Justin

The mesh on the racks of these Chinese machines is never really good, but is not usually a problem. The return spring usually takes up the back lash by applying upward pressure while down feeding.
With you saying the quill drops when down feeding, I would say the spring needs to be tensioned.

Dave

It only does the serious clunk and drop down in one spot.

The clunk is clearly audible and readily repeatable at the exact same spot.

And it drops the same amount each time.

I'll inspect things more closely on the weekend.

The mill is such a contrast to my Unimat Compact 8 lathe. Made in Austria and it just plain works!

You want to machine off .05 mill of a diameter just dial up 0.025.

Maybe I have been spoiled.

Cheers

Justin

Quick Update:

I pulled apart the return spring, fine quill feed and pulled out the pinion shaft.

I can't really fault the quill fine feed, it actually looks quite well machined both the gear and the worm.

The pinion shaft seems to have about 0.2mm run out when I set it up in my lathe, I doubt that would make any difference. Will more closely check straightness over the weekend.

The pinion teeth themselves look fine, without detailed measurement, there is nothing obviously wrong.

Just for fun I but the pinion shaft in without the return spring but at a different index position. The result was no more clunk so I might but the pinion in 180 degrees opposite to it's original position.

The quill itself moved quite freely overall but was looser at the start of it's travel downward than at the end of the downward travel.

The quill felt quite firm with no detectable lateral movement. (by feel only)

Will have a more detailed look at the rack over the weekend.

Cheers

Justin

Hi Justin,
Thinking about it, it sounds like the quill is sticking and then dropping down. I would give the quill and bore a clean and a light oil and reinstall it to see if that helps. Once the pinion shaft is out, the quill should come out easy.
The quill might have some of that gummy preservative in it causing the problem.

Dave

Originally Posted by Dave J

Hi Justin,
<snip>
The quill might have some of that gummy preservative in it causing the problem.

Dave

Hi Dave, it might be that chicken fat that they grease the HM52's with...

Regards
Ray