HF 5980 Graduated Collars conversion confusion

This forum is dedicated to those hobbyists with the 3-in-1 metalworking machines. Mill-Drill-Lathes. Tips, techniques, modification and use of these machines is topical.

Moderator: Harold_V

Post Reply
BentTooner
Posts: 20
Joined: Sun Nov 27, 2011 7:50 pm

HF 5980 Graduated Collars conversion confusion

Post by BentTooner »

12-2-11
Hi, all

I recently got a Harbor Freight 5980 "3 in 1" machine. I may be weird, but I found the markings on the 5 graduated collars confusing. After some measuring with a digital caliper, I decided the graduations on the various collars are in millimeters. Since I don't think in metric units, that's the beginning of the confusion for me.

Then, I realized that the collars have a different number of 'tick' marks for one complete turn and the tick marks represent different parts of a millimeter. The letter "u" is stamped on each collar along with a value. For example, the tail stock collar is stamped "u=0.035." I decided the "u" might mean "units." If so, this translates to "1 tick mark = 0.035mm." This seems about right after measuring with my digital caliper.

That was a break-through for me, but I still don't think in metric and I find it hard to remember how many tick marks each collar has. For example, while the tail stock and Y-axis collars have 50 ticks, the X-axis and Tool Post collars have only 40 ticks. And, the mill head has 105 ticks (but it only moves through 56 of them)! Also, the stamping on the collars makes it hard to determine the final number. Finally, in each case, 1 tick mark represents a different part of a millimeter!!

I decided to make a chart to help me remember and convert each collar's graduation marks into inches. For example, the fine feed collar on the Tool Post has 40 tick marks and each mark represents 0.05mm. To convert from mm to inches, divide by 25.4. So, each tick is almost 0.002".

If you make one complete turn of the Tool Post fine feed collar, you should advance 2.0mm (40 ticks x 0.05mm per tick = 2.0mm). Also, since there are 40 ticks in one turn and each tick is almost 0.002", one complete turn is about 0.080" (40 ticks x 0.002" per tick = 0.080").

For example, to move 0.420" on the Tool Post fine feed, you need to move 210 ticks (0.420 / 0.002 = 210). I found in using the machine that I tend to count in terms of "turns & ticks." One complete turn of the Tool Post fine feed wheel is 80 thousandths, so 5 complete turns would be 0.400 plus 5 ticks would give you 0.420". To me, that's "5 turns & 5 ticks."

Here's what I found (ignoring rounding errors):

TOOL POST feed handle: 40 ticks=1 turn=0.079” 1 tick = 0.002”
TAIL STOCK wheel: 50 ticks = 1 turn = 0.069" 1 tick = 0.0014”
X-AXIS feed wheel: 40 ticks = 1 turn = 0.157” 1 tick = 0.004”
Y-AXIS feed wheel 50 ticks = 1 turn = 0.118” 1 tick = 0.0024”
MILL HEAD feed handle: 105 ticks but limit is 56 ticks=1 turn=3.087" 1 tick = 0.055"

That's helpful to me, but what if I want to advance in fractions of an inch? For example, maybe I want to make a hole 9/32" deep or remove 5/32" from a surface. I have to convert the fraction to inches and then convert the inches to ticks. (I have some charts to convert fractions to inches in the shop but they don't, of course, do the final conversion to tick marks for the HF 5980 wheel in question. Lots of chances for me to screw up...)

I decided to make a Collar Cheat Chart for each collar to help with all this. That turned out to be a lot of work so I wrote a computer program in Java to calculate these values through 1 inch given the input of how many ticks=1 turn, what each tick represents in mm and how many increments of an inch you want (1/32" would be 32 increments). That way, I can quickly and accurately calculate these values for any metric collar (not just the HF 5980).

Here's part of the chart I got for the TOOL POST fine feed up thru 1/4". (I actually made the chart thru 1".) For example, to move 1/8" using the tool post fine feed handle, I should turn the handle one complete turn PLUS 23.5 ticks:

TOOL POST - fine feed handle
"Turns & Ticks" for 1/32” 40 ticks=1 turn=0.079” 1 tick = 0.002”
Fraction Decimal Complete Turns Ticks
1/32” 0.03125” 0 15.875
1/16” 0.0625” 0 31.75
3/32” 0.09375” 1 7.625
1/8” 0.125” 1 23.500
5/32” 0.1562 1 39.375
3/16” 0.1875 2 15.250
7/32” 0.2188 2 31.125
¼” 0.25 3 7.0

I have no idea if this helps anyone else or if I'm missing something. I have these Cheat Charts now for all 5 collars:
1) tool post
2) tail stock
3) x axis
4) y axis
5) mill head

I can create the fraction charts through 1" in any increment, for any metric collar given the number of ticks in one turn and the mm per tick.

I recognize one could adapt and add various instruments to the machine in order to get a direct read out (home made DRO?) and I also recognize that the machine is never going to produce work at these tolerances. But, I felt it was useful to go through the process and at least have some idea what I am doing when I'm turning the wheels.

Sorry for the length of this post. Maybe it will help someone...
Torch
Posts: 1684
Joined: Wed Mar 17, 2010 7:58 am
Location: Muskoka

Re: HF 5980 Graduated Collars conversion confusion

Post by Torch »

Nice job on the math. Here's another possible solution for consideration:

DRO.

Installing a digital readout is a great boon in this regard. Now, a purist such as Harold will justifiably argue that a DRO is a crutch and will impair the ability of the beginning machinist to flexibly work on machines that are only equipped with dials. That is a perfectly valid concern when training a new apprentice. However, if your home machine is the only one you intend to use for the forseeable future, then the DRO will removed one variable and allow you to concentrate on other aspects.

The DRO will not change the sensitivity of the wheels. If the cross-slide wheel needs more turns per cm or inch than the carriage wheel, that will remain the same. The DRO is just a fancy ruler. Some are a little fancier than others and have functions like bolt-hole circle or angle calculators to help position the tooling. With shipping, a 3-axis "Sinpo" DRO kit with scales and brackets can be had for under $500 on eBay and the 3-axis mode works well with a 3-in-1.

A "poor man's DRO" consists of simply mounting direct reading digital scales to the desired axis. No fancy calculators and memories, but simple and fairly cheap. In between are the really basic DRO units that are based on digital scales, but add a nice large-digit readout.

Just a thought...
User avatar
Dan
Posts: 38
Joined: Wed Jun 22, 2011 6:09 pm

Re: HF 5980 Graduated Collars conversion confusion

Post by Dan »

Edit, out of stock/no longer available parts.
Dan
Post Reply